Venezuelan Tepuis their caves and biota

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Acta Geologica Slovaca AGEOS – Monograph AGEOS EDITOR-IN-CHIEF: Michal Kov AGEOS EXECUTIVE EDITOR: Rastislav Vojtko BOOK MANAGING EDITORS: Roman Aubrecht and Jn Schlgl LANGUAGE REVISION: Raymond Marshall GRAPHIC DESIGN: Janka Blik Comenius University in Bratislava, FULL REFERENCE OF THIS BOOK Aubrecht R., Barrio-Amors C.L., Breure A.S.H., Brewer-Caras C., Derka T., Fuentes-Ramos O.A., Gregor M., Kodada J., Kovik ., Lnczos T., Lee N.M., Lik P., Schlgl J., mda B. & Vlek L. : Venezuelan tepuis: their caves and biota. Acta Geologica Slovaca – Monograph, Comenius University, Bratislava, pp. Research and this publication were supported by Slovak Research and Development Agency Projects APVV and APVV -, and by grants of Ministry of Education, Science, Research and Sportof the Slovak Republic VEGA // and VEGA //. ISBN: 978-80-223-3349-8 Cover: Roraima Tepui from the E, with Kukenn and Yuruan tepuis behind. Photo: Charles Brewer-Caras


Authors (in alphabetic order): Roman Aubrecht Csar Luis Barrio-Amors Abraham Breure Charles Brewer-Caras Tom Derka Oswaldo A. Fuentes-Ramos Milo Gregor Jn Kodada ubomr Kovik Tom Lnczos Natuschka M. Lee Pavel Lik Jn Schlgl Branislav mda Luk Vlek


CONTENTS 1. PREFACE 2. CAVE SYSTEMS IN CHUR AND RORAIMA TEPUIS – GEOMORPHOLOGY, SPELEOGENSIS AND SPELEOTHEMS 2.1. Introduction – studied areas, geological seing and climatic conditions 2.2. History of cave exploration on tepuis 2.3. Charles Brewer Cave System 2.3.1. Introduction 2.3.2. Localization 2.3.3. Charles Brewer Cave System: basic description Cueva Zuna Cueva del Diablo Cueva Charles Brewer Cueva Muchimuk Cueva Colibr 2.3.4. Cave spatial amework 2.3.5. Speleological perspectives 2.4. Ojos de Cristal Cave System 2.4.1. Introduction 2.4.2. Localization 2.4.3. Ojos de Cristal Cave System – basic description Cueva Mischel Cueva Ojos de Cristal Cueva del Hotel Gucharos Cueva de los Pmones Cueva Asxiadora and Cueva de Gilberto 2.4.4. Cave spatial amework 2.4.5. Speleological perspectives 2.5. Hydrogeochemistry 2.5.1. Sampling of natural waters and related eldwork 2.5.2. Results of geochemical investigations 2.5.3. Processes inuencing the water chemical composition 2.6. Speleogenesis of the Charles Brewer and Ojos de Cristal cave systems. 2.6.1. Introduction 2.6.2. Material and methods 2.6.3. Results and interpretations Field geomorphological and geological observations and their importance in speleogenesis Hardness measurements Mineralogy and petrology of arenites and red muds 2.6.4. Discussion Cement dissolution versus non-cementation Importance of “Barro Rojo” Descending diagenetic uid ow and possible origin of tepuis 2.7. Speleothems 2.7.1. Introduction 2.7.2. Inorganic siliceous speleothems Siliceous stalactites Flowstone crusts “Cobweb stalactites” (teleraas) Mineralogical composition of siliceous speleothems 2.7.3. Biospeleothems 2.7.4. Non-siliceous speleothems “Barro Rojo” Gypsum Sanjuanite 2.7.5. Discussion Speleothem size Sources of silica Geomicrobiology Cobweb stalactites 2.8. Conclusions 47 47 49 49 49 50 56 60 60 66 67 72 72 76 76 76 76 80 80 91 91 94 94 98 98 101 103 108 109 7 9 9 13 20 20 23 25 25 25 25 26 27 27 28 28 29 32 33 33 33 33 34 35 35 36 37 37 37 40


3. FAUNISTIC INVESTIGATIONS OF PANTEPUI BIOGEOGRAPHICAL REGION 3.1. e Pantepui malacofauna: land snails of Chur Tepui and other tepuis in southern Venezuela and adjacent areas 3.1.1. Introduction 3.1.2. Material and methods 3.1.3. Land snails in a hostile habitat 3.1.4. Systematics Species of Macizo del Chimant Species om other tepui areas Eastern Pantepui region Central Pantepui region Western Pantepui region Southern Pantepui region 3.1.5. Morphological and phylogenetic analyses 3.1.6. Discussion 3.2. Major groups of aquatic insects of Pantepui 3.2.1. Introduction 3.2.2. Material and methods 3.2.3. Sampling area and localities 3.2.4. Ephemeroptera Introduction Results and Discussion 3.2.5. Plecoptera Introduction Results and Discussion 3.2.6. Trichoptera Introduction Results and Discussion 3.2.7. Orthoptera Introduction Results and discussion 3.2.8. Coleoptera Introduction Results and discussion 3.3. Herpetofauna of the “ Lost World ” 3.3.1. Introduction 3.3.2. History of herpetological collections in the “Lost World” 3.3.3. Results Cerro Autana Auyn Tepui Chimant Massif Roraima Sarisariama 3.4. Conclusions of the faunistic investigations in the Pantepui ACKNOWLEDGEMENTS REFERENCES 140 140 143 145 145 149 149 151 152 113 113 113 115 117 117 117 118 118 120 120 120 122 122 124 124 125 125 128 128 129 130 130 132 132 132 133 137 137 137 139 139 139 140 140 140


1. Preface e world at the top of the tepuis of Venezuela is amazing. Ever since Sir Arthur Conan Doyle wrote “e Lost World”, the enig ma of the South American steep and isolated table-mountains have aracted many people. Everyone in our research team dreamt about exploring these “blank spaces on the map”. How ever, despite this great araction, scientic literature concerning tepuis has remained rather scarce. We are therefore proud to pre sent this scientic monograph on tepuis, which is considered to be only the second issue of its kind, following the work of Huber (1992). is volume summarizes the main scientic results of expeditions to these tepuis between 2002 and 2011. e major research described in this monograph is dedicated to the great caves discovered in Roraima and Chur tepuis. e geological research was accompanied by biological research on cave and surface fauna, with a special focus on malacofauna, herpetofauna and insects. Although some of the data from this research has been previously published in scientic articles, it did not always obtain the justiable space to present all gathered documentation and to elucidate all relevant scientic problems from a greater perspective. It is therefore our great pleasure to present this monograph containing detailed information on all research cur rently performed by our interdisciplinary research team. is is accompanied by a large number of fascinating photographs and several informative maps and diagrams. e greatest benets to be gained from this combined monograph compared to short scientic publications is that more space is available to discuss currently unresolved problems, to ponder new intriguing ques tions and to envisage future necessary research. It is our sincere hope that all our readers will appreciate the unique information presented in this manner, and we hope you will really enjoy this monograph and nd interesting topics for your research. –


2.1. INTRODUCTION STUDIED AREAS, GEOLOGICAL SETTING AND CLIMATIC CONDITIONS e main feature of the area of Guyana, encompassing southern Venezuela, northern Brazil and Guyana are its tepuis. ese tepuis are table-mountains composed of Precambrian quartzites and sandstones from the Guyana Shield, rimmed by steep cli walls. More than 100 table-mountains can be found in this area, and the tepuis provide important habitats for a great variety of endemic ora and fauna. eir isolated environments produce interesting and authentic laboratories harbouring dierent kinds of evolutionary processes. Many organisms show signs of end emism, oen tied to one specic tepui where their individual evolution took place. An example of this can be found in Chapter 3 which summarizes the results of zoological research focused on malacofauna and the fauna of reptiles, amphibians, and insects. Karst structures with large subterranean systems were also dis covered during the exploration of these tepuis’ isolated environ ments. e Chapter 2 devoted to this phenomenon describes their speleology and geomorphology, and also elucidates the genesis of these cave systems and the origin of their unique speleothems. From a geological viewpoint, the caves and surface areas ex plored herein are situated in the Venezuelan Guyana, in the northern part of South America (southeastern Venezuela – Gran Sabana, Bolvar State, Fig. 1). e Gran Sabana area comprises Archaean rocks of the Guyana Shield which is the northern part of the Amazonian Craton. e Guyana Shield has a Proterozoic sedimentary cover formed by Roraima Supergroup sediments which are mainly clastics derived from the northern Transama zonian Mountains (Fig. 2). Sedimentological studies showed that the depositional environments ranged from alluvial fans to uvial braided-river deposits together with lacustrine, aeolian, tidal, shallow-marine deposits and some shallow water turbidites (Reis & Ynez, 2001; Santos et al., 2003). Sandy continental deposits are dominant here. e Roraima Supergroup mainly forms tabular plateaus (tepuis), cuestas and hogbacks which rise steeply above the Paleoproterozoic basement (Fig. 3). e thick ness of the group ranges from 200 m to approximately 3000 m, and it consists of the following lithostratigraphic units arranged in stratigraphic order (see Fig. 4); the Arai Formation, Suapi Group, Uaimapu Formation and the Matau Formation (Reis & Ynez, 2001). Tepuis developed mainly in the uppermost, Matau Formation formed by quartzites and sandstones. eir age was determined as 1873 3 Ma (Late Paleoproterozoic), based on U-Pb analyses of zircons from a green ash-fall tu of the Uaima pu Formation (Santos et al., 2003). Since most of the previous authors accepted the theory that quartz dissolution require a long time, the recent landscape, including commencement of the cave-forming process, is considered to be inherited from the Mesozoic period (e.g. Cretaceous – see Galn & Lagarde, 1988; Briceo et al, 1991). However, there is currently no supporting data for this estimation. e oldest datings (U-) of siliceous speleothems provide only the Pleistocene ages (Lundberg et al., 2010 a ). e speleological research of our team started in 2002 with the discovery of the Ojos de Cristal Cave System, which is cur rently estimated to be the second longest discovered sandstone cave system in the world as discussed in chapters 2.2. and 2.4. e geological and geochemical data presented in this chapter were collected in expeditions during the 2007 and 2009 dry seasons. e main research targets of these expeditions were the geomorphological forms on the surface of the Chimant Massif (the partial plateau named Chur Tepui) and Roraima Tepui, as well as the caves in these tepuis which form the two largest sand stone cave systems in the world: the Charles Brewer Cave System (mda et al., 2010) and the Ojos de Cristal Cave System (mda et al., 2003). Dierent types of geochemical and geotechnical measurements were performed in the largest cave in the Charles Brewer Cave System – the Cueva Charles Brewer (Fig. 16), as well as in Cueva Caon Verde, Cueva Colibr sector and Cueva Juliana. Sampling was also taken from Cueva de los Pmones and Cueva de Gilberto in the Ojos de Cristal Cave System (Fig. 26). e climate in the wider area of the Gran Sabana is mainly inuenced by meteorological conditions in the tropical Atlantic Ocean. e sea surface temperature (SST) meridional gradient over the tropical Atlantic has a profound impact on the climate and weather conditions in the Gran Sabana area, which is lo cated in the eastern part of South America. Several additional parameters may also exert either direct or tele-connected indirect atmospheric inuence on climate variability over South America. is inuence also extends to high-latitudes (Garraud et al., 2009) by high-latitude forces such as the Antarctic Oscillation (AAO), the North Atlantic Oscillation (NAO) and the El Nio Southern Oscillation (ENSO) phenomena, rooted in the ocean. During the last decade, climatologists have therefore begun to describe the climate of the northern and central part of this continent as monsoon-like (for further information, please see the updated review of the “South American Monsoon System r SAMS]” by Vera et al., 2006). 2. Cave systems in Chur and Roraima tepuis – geomorphology, speleogenesis and speleothems –


– Fig. 1: Location of the examined tepuis. Fig. 2: Geology of the Guyana Shield – from Voicu et al. (2001).


e climate of the Gran Sabana region has been classied as tropical, because of its extremely humid headland climate (Galn, 1984). According to climatic data from the Kavanayen meteorological station, the annual precipitation of 2,548 mm is unevenly distributed, with a mean monthly rainfall of 60 mm during the December to March dry season (Hernndez, 1994). Unfortunately, only a few authors have currently presented climatic data measured directly on the mesetas of the tepuis (Steyermark, 1967; Huber, 1976; Colonnello, 1984; Galn, 1992). According to their ndings, the Chimant region is char acterized by a tropical climate, with an isothermic regime due to its geographical latitude. However, the climatic conditions on the mesetas of the tepuis are quite dierent to those in the Gran Sabana surrounds. e main dierences consist of lower average temperatures and considerably higher rainfall, result ing in extreme humidity. Although the thermal conditions are quite uniform throughout the year, remarkable oscillations of the temperature may occur on a daily basis. While the medium annual thermal oscillation is only around 2 C, the medium daily oscillation oen exceeds 10 C (Galn, 1992). e vertical thermal gradient is 0.6 C (Rhl, 1952). Lower annual medium temperatures were recorded with increasing height: these were 21 C at 1,000 m a.s.l. and 13.9 C at 2,200 m a.s.l. (Galn, 1992). e mean annual rainfall at 2,200 m a.s.l. is approximately 3,351 mm (Galn, 1992). Normally, only the rst part of the year from January to March is quite dry (Fig. 5), with the rest of the year characterized by diering amounts of rainfall. e rainy season generally begins in mid April and ends in Decem ber, with the highest rainfall recorded from May to September. Dierent total annual rainfalls have been recorded dependent on height and region. For example, 2,500 mm was registered at 1,200 m a.s.l. on lowlands in the Kawanayen area, and 3,600 mm on the highest part of the meseta at 2,420 m a.s.l. A summary of the rainfall distribution and the main wind direction and circulation is depicted in Figure 6. Based on this gure, it is quite obvious that rainfall increases with height, which in turn creates a cloudy level around the higher parts of the walls and mesetas. ese conditions consequently induce both the cold and the extremely humid climatic conditions on the mesetas, and also the higher rainfalls around them especially during the rainy season. Since the retention capacity of the soil and the massif creat ing the karstic aquifer is rather weak, surface and underground stream discharges become strongly dependent on the actual rainfall. e stream discharge response to rainstorms is therefore usually very rapid. A perfect example of this is the underground . rf f – nfnr, n f Fig. 3: Example of tepuis – tabular plateaus formed by arenites of the Roraima Supergroup, covering the Guyana Shield. Tirepn Tepui, Chimant Massif.


Fig. 5: Annual rainfall distribution on the mesetas of Chimant Massif and Auyn Tepui, according to data published by Galn (1992). Fig. 4: Lithostratigraphic scheme of the Roraima Supergroup and its depositional systems. From Santos et al. (2003), slightly modied. –


stream of the Cueva Charles Brewer, where an average rainfall event can cause a water level increase of approximately 6 metres in a few hours (Fig. 7). As mentioned above, there is very lile data available for table-mountain climatic and hydrologic conditions, and, con sequently, longer time-series data for temperature, rainfall, evapo-transpiration and stream discharges are unfortunately lacking. ese data are necessary for evaluation of impacts from climatic changes and, in combination with hydrogeochemical data, they are mandatory for correct evaluation of the overall mass transfer rate from the table-mountains to the lowlands. 2.2. HISTORY OF CAVE EXPLORATION ON TEPUIS e table-mountains of the Guyana Highlands currently remain an ever-lasting treasure-trove for dierent types of scientic Fig. 7: Rapid water level changes in underground surface streams. A – View of the entrance of Cueva Charles Brewer; the dashed line denotes the approxi mate cave water level during the maximum observed water level a few hours after heavy rain. B – The water level in the stream close to the entrance of the Cueva Charles Brewer. The arrow points to the water level at the same site as in picture A. C – Ro Olinka depicted during a dry period. D – Ro Olinka shown shortly after heavy rain. Fig. 6: Rainfall and temperature distribution in the area of the Chimant Massif, according to Galn (1992). . rf f – nfnr, n f


discoveries. ey were rst described by the royal surveyor Robert Schomburgk in 1838, and the rst expedition to the Roraima Tepui meseta was led by Sir Everard im urn and Harry Perkins in 1884. Since then, several hundred general sci entic expeditions, including tens of speleological expeditions, have explored these mountains, and fascinating discoveries including numerous novel species and unique caves have been made on virtually every trip. Early speleological explorations of the quartzite massifs of the Guyana Highlands began on the Autana Tepui – a gigantic rock pillar towering 1,300 m above the Venezuelan Amazonia (Brewer-Caras, 1972, 1973 a , 1976 a ; Colve, 1972, 1973; Ur bani &Szczerban, 1974; Szczerban & Gamba, 1973; Szczerban & Urbani, 1974; Galn, 1982; Prez La Riva, 1976; Prez La Riva & Reyes, 1976; Urbani, 1976 a ; Owen, 1978). Speleologi cal explorations then continued on the Jaua-Sarisariama – an extensive meseta hidden in the deep jungle of the Ro Caura River Basin (Urbani &Szczerban, 1974; Szczerban &Urbani, 1974; Szczerban & Gamba, 1973; Brewer-Caras 1973 b , 1976 b ; No, 1975; Urbani, 1976 b, c ). e cave on the Autana Tepui (Fig. 8) was rst described in 1757 as a portal resembling a large stone eye set in the 800 m southern wall (Gilij, 1780). Although this was visible from a long distance, no further detailed explorations were performed in those days. e rst actual speleological expeditions were led by the naturalist Charles Brewer-Caras in the early 1970s. To the amazement of the entire party, they discovered that this cave consisted of several fascinating horizontal passages up to 395 m in length. ese entered the walls from several dierent locations, suggesting inter-connections throughout the entire mountain range (Brewer-Caras, 1970, 1972). Further speleological explorations were then described by other intrepids, including Urbani & Szczerban (1974) and Brew er-Caras (1976 b ). During these expeditions, the Venezuelan scientists made several important discoveries, including the new mineral fl 7 [Cl|(OH) 8 |(NO 3 ) 2 ] 2 8H 2 O, named sveite aer La Sociedad Venezolana de Espeleologa (SVE) (Martini, 1980; Martini & Urbani, 1984). e Cueva del Cerro Autana became the rst quartzite cave explored in great detail. e unique nature of this cave raised many intriguing questions, such as; i) was the cave created by an underground river, as indicated by erosion marks on the cave walls?; ii) when was the cave created – was it during a time when the surrounding land was eroded several hundred metres deep?; iii) where did the river ow?; and above all, iv) do other similar caves exist, also formed by this ancient river on other table-mountains in this area, and also in other parts of the world? ese intriguing questions will hopefully be answered by future explorations of the other table-mountains throughout the world. However, it was obvious from the start that this would not be an easy quest because the many expected diculties were indeed encountered. e rst problem, of course, was limited access to the area, with helicopters supplying the only means of overcoming the 900 m steep walls of the Autana Tepui to reach the Cueva del Cerro Autana. Morever, this helicopter had to be small enough to land and manoeuvre on the meseta, so that the exploration party could descend 150 metres on a rope-ladder to the cave entrance. e surface of the extensive meseta of the Sarisariama Tepui is covered by dense jungle vegetation at 2,300 m a.s.l. Although it looks at, the meseta is in fact characterized by huge vertical depressions with diameters up to 350 m and by steep walls of this same depth (Fig. 9). e huge passages running o these depressions form entrances into the rock massif, thus making it obvious that discovery of these unique caves would have been impossible without such manoeuvrable helicopters. e depressions of Sima Mayor with depth of 314 m and Sima Menor with depth of 248 m on the Sarisariama Tepui are drained by springs several kilometres distant (e.g. BrewerCaras, 1973 b , 1976 b, c ; Urbani & Szczerban, 1974; Szczerban & Urbani, 1974; Szczerban & Gamba, 1973). Detailed mapping of these depressions showed that based on the total measured volume of 18 million m 3 , the Sima Mayor Abyss can be classi ed as one of the largest known karst cavities in the world. Two cave segment branches enter in opposite directions from the lowest part of the smaller depression known as Sima Menor (or Sima Martel sensu De Bellard, 1974 a,b , 1975; or Sima Gibson sensu Brewer-Caras, 1974, respectively). ese are called Cueva de la Cascada and Cueva de los Gucharos. Another huge karstic collapse called Sima de la Lluvia Cave is situ ated close to these sites. is one is 1,352 m long, including its Cueva de los Cristales branch. Due to the unique nature of these caves, two expeditions explored this site within a short period. e rst expedition was led by Charles Brewer-Caras Fig. 8: Autana Tepui – where the Venezuelan quartzite speleology originated. –


who, together with his team, described their work in papers wrien in the 1970s (e. g. Brewer-Caras, 1973 b , 1976 b ) and in a beautiful popular-scientic book (Brewer-Caras, 1983). Another, Polish-Venezuelan expedition was led by Franco Ur bani. eir work is described in various speleological papers (as in Zawidzki et al., 1976; Dyga et al., 1976; CEDV, 1976), and also in popular–scientic papers and short notes (Kuczynski, 1976 a, b ; Koisar & Solicki, 1977 a, b ). Several additional caves have been discovered on other Venezuelan table-mountains, as briey summarized below in chronological order: – e G1-G3 caves, with overall length of 130 m on the Guaiquinima Tepui, were described by Szczerban et al. (1977) and Urbani (1977). – Several caves (assigned with the Bo. 4 – Bo. 7 – numbers ac cording to the list of the Bolvar State in the National Speleological Cadastre) on the uplands of the Sierra Pacairima (Pacaraima) are described in papers by Urbani (1977) and Prez La Riva (1977). – Cueva (Sima) Kukenn in the mountain of Kukenn (Ma tau) Tepui was described by Perz La Riva et al. (1986 a ), Mi chelangeli et al. (1993), and Doerr (1999). – All caves discovered on Yuruan Tepui (Galn, 1986), Sierra Marutani (Bo. 9 – Bo. 19), Kukenn Tepui (Bo. 22 – Bo. 25), Acopn andAmur tepuis (Bo. 40 – Bo. 53), Cerro Chirikayn (Bo. 90 – Bo. 91) as well as the short caves in the Ro Aponguao River Basin (Bo. 20 – Bo. 21). ese caves are described by the National Speleological Cadastre – Catastro Espeleologico Na cional (earlier Catastro Espeleologico de Venezuela). – Several dierent caves (Galn, 1988) on mountains and partial massifs of Sarisariama (3 caves), Guaiquinima (9 caves), Eutobarima (1 cave), Aonda (8 caves), Urutany (2 caves), Auyn Tepui Norte (1 cave), Tramn (1 cave), Aguapira (15 caves), Kukenn (5 caves), Roraima (1 cave) andYuruan (2 caves), in the foreground of the table-mountains near Santa Elena de Uairn – El Pauj (4 caves) and on the mountain of Aponguao (2 caves), Serrania Perea (2 caves), Chimant (1 cave) andAu tana (3 caves). 60 quartzite caves with 14,504 m overall length were located in the Estado Bolvar (57) andTerritorio Federal Amazonas (3), according to Galn (1988). – One large cave which is considered insignicant due to doubt over its continuation was discoverd on the Il Tepui (Bo. 33), and there are also several abris (crepuscular caves) and pseu dokarst caves noted; for example in the Districto Cedeo (Bo. 56 – Bo. 82). Fig. 9: Sarisariama Tepui plateau with the huge Sima Mayor Shaft 300 m in diameter. . rf f – nfnr, n f


– Some caves have also been discovered on the Chimant Massif (Maeztu et al., 1995; SVE, 1994) and Roraima (Fig. 10). – Approximately 100 quartzite caves were listed by Ghneim (1999) in his bibliography of the Venezuelan caves. Of these, 91 were located in Bolvar State (names marked with the ab breviation Bo.). e remainder were located in the territory of Amazonas (names marked with Am., as in the Cueva del Cerro Autana). Since then, other quartzite caves have been discovered in the same area. For example, according to the Catastro Espele olgico Nacional, there were 107 known caves in Bolvar State in 2006, and most of these were formed by vertical cracks and/ or short underground passages. anks to international expeditions led by Venezuelan, Ital ian and Polish research leaders, cave research in this area has expanded continuously since the 1980s. During this period, several novel fascinating caves and cave systems were discovered. ese included deep tectonic valleys and crevices, up to several hundred metres in depth and inter-connected by underground passageways. eir water was derived from rainwater drain ing from the surface along the impermeable base of the tablemountain. Some of these expeditions received public aention, especially the discovery of the Sima Aonda Cave located on the meseta of the Auyn Tepui (2,560 m a.s.l.). With its 383 metre depth, this was considered the deepest quartzite cave in the world for many years. e caves from the Auyn Tepui were described by Galn (1983 a,b , 1984), Perz La Riva et al. (1986 b ), Inglese & Tognini (1993), Pezzolato (1993, 1996), Piccini (1994), Gori et al. (1993), Bernabei et al. (1993), Carreo (1996), Piccini et al. (1994), Mecchia et al. (1994) and also in themonographic issue of the journal Progressione (Bernabei, 1994). In the 1990s the Sima Aonda Superior Cave with its dimensions of 2.1 km length and 320 m depth (later re-evaluated to 362 m) (Bellomo et al., 1994; Forti, 1994; Martnez, 1989; Tognini et al., 1995; Urbani & Bordn, 1997) was surpassed by the Sima Aonda 2 Cave with its depth of 325 m, and also by Sima Aonda 3 Cave with its depth of 335 m which were discovered by Italian speleologists. Later, the 2,950 m long and 370 deep Sima Auyn Tepui Noroeste assumed supremacy in size (Bernabei et al., 1993; Bernabei, 1994; De Vivo et al., 1997; Piccini, 1995; Mecchia & Piccini, 1999). Urbani (1993) listed six quartzite caves longer than 1 km and 13 caves longer than 2 km, together with 13 caves deeper than 200 m and 13 caves deeper than 250 m. ese impressive publications by the Italian speleological group La Venta showed that the Auyn Tepui caves are in fact an extensive system of gigantic tectonic crevices, called “grietas” in Spanish. ese grietas are intercon nected by smaller-scaled sub-horizontal channels. e draining function of this underground system is quite clear, however there are some disputes about whether the above-listed localities are “caves” or “karst phenomena” . According to recently accepted classication, only the channels interconnecting the grietas can be acknowledged as karstic caves. eir documented depths and lengths are enlarged by adding the vertical sectors of the grietas. At the end of the 1990s Brazilian cavers explored the following caves; (1) the two crevice caves Grua do Centenario (3.8 km long, 481 m deep) and Grua da Bocaina (3.2 km long,404 m deep, which are ranked the 4 th and th longest quartzite caves in the world). ese are located on the massif Pico do Incionado in Minas Gerais State; (2) theGruta Alaouf Cave (1.2 km long, 294 m deep) was also described there (Faverjon, 2003; Auler, 2002, 2004; Rubbioli, 1996, 1998, 2001, 2003; Dutra 1996 b , 1997; Hirashima, 1997; Perret, 2001; Sausse, 2001; Chaimovicz, 2001; Rodrguez & Silverio, 2002; Dutra et al. 2005); and (3) other quartzite caves were described in the southern part of the Minas Gerais State (as in Dutra, 1996 a ). According to Rubbioli (1996) the rst map of a quartzite cave was prepared in 1952. is cave is currently known as Grua do Centenario and its characteristics suggest a tectonic origin, with only secondary contributions to its morphology from dissolution processes . Although it had previously been referred to controversially as “pseudokarst” in some parts of Europe, quartzite karst has now been described in many sites throughout the world under its correct title. Although quartzite caves can also be found in other territories besides the Guyana Highland, most of these are rather small. Examples of these small caves include; (1) the quartzite caves on the Mato Grosso Upland and in the state Minas Gerais of Brazil (as in Travassos et al., 2008; Wernick et al., 1977; Auler, 2002; Willems et al., 2005, 2008); (2) the 1.4 km long Caverna Aroe Jari Cave in the Mato Grosso Plateau was described by Borghi & Moreira, (2000, 2002); and (3) caves of this type have Fig. 10: Roraima Tepui table-mountain, “the Prova” northern vertical wall is 600 m high. –


also been discovered in several African states, including Chad, Niger, and Algeria (as in Busche & Erbe, 1987; Sponholz, 1989, 1994 a, b ; Willems et al., 1996). However, several large quartzite caves have also been found at locations other than the Guyana Highland. ese include those in South Africa, which harbours twenty of the longest quartzite caves, including Magnet Cave (2,490 m; Martini, 1990, 1994) and a Bats/Giants/Climbers Cave System (1,632 m; Truluck, 1996; Martini, 1981, 1982, 1984, 1985, 2000). e Czech Republic boasts the 27.5 km long crevice system in quartz sandstones called Poseidon (Mlejnek & Ouhrabka, 2008), which is predominantly open to surface, thus not a real cave. e Meghalaya area on the India/Bang ladesh border has thefamous 1,297 m long Krem Dam Cave (Oldham, 2003). Although the website states that the Krem Dam Cave was formed in acoarse-grained facies of limestone which looks almost like sandstone, Breitenbach et al. (2010) reported only sandstone caves in the Meghalaya State. ese are in fact sandstones with quartz grains and carbonate matrix mixed with sandy limestones with quartz grains. In ad dition, pseudokarstic features have also been reported from Queensland, Australia (Wray, 2009). An important year for quartzite speleology was 2002, when a unique cave was discovered by Slovak and Czech cavers Zoltn gh and Marek Audy on the meseta of the Roraima Tepui – Cueva Ojos de Cristal (mda et al., 2003). is meseta has a highest peak of 2,810 m a.s.l., and it borders three countries: Venezuela, Brazil and Guyana (Guayana Essequiba, the Reclamation Zone claimed by Venezuela). Although Roraima is very well-known due to Charles Brewer-Caras’ text (Brewer-Caras, 1978), the real boom in quartzite cave discoveries began with the Czech-Slovak expedition in 2003 (Audy, 2003, 2008; Audy & mda, 2003; mda et al., 2003; Vlek, 2004). is team discovered a very unique extensive continuation of the cave, together with other horizontal underground passages on the table-mountain. is . rf f – nfnr, n f Fig. 11: Gladys Lake at the end of a shallow rocky valley on Roraima Tepui – the ponor zone of Cueva de los Vencejos which was explored by Charles BrewerCapriles and Jos Miguel Prez in 1990.


discovery was a historical break-through, because it presented a much beer approach to understanding the quartzite karst phenomenon in the Guyana Highland. Such an extensive inlet/ outlet cave system, with its huge variety of morphological forms as described by the Czech-Slovak team is unique on a world scale. Besides the Cueva Ojos de Cristal, no other uvial active system of horizontal passages measuring several kilometres was known in any massif in the world (Fig. 12). is cave was explored in great detail during the 2003 and 2007 expeditions. For a time, it was regarded as the longest in Venezuela (surpassed recently by the discovery of the 18,200 metre long Cueva El Samn limestone cave), and it was classied as the longest quartzite cave in the world shortly aer its discovery. Aer 2006, its dimensions were documented at 15,280 m long and 73 m deep (Vlek & mda, 2007). Shortly aer presentation of exploration results from the Cueva Ojos de Cristal in 2004/2005, a Venezuelan-SpanishEnglish speleological team re-mapped the same cave at 10,580 metres and renamed it Cueva Roraima Sur. is was despite the name Cueva Ojos de Cristal having been codied since 2003 and already quoted in all English-language literature (mda et al., 2005 a, b ). eir exploration results were published (with foredate) in the Bulletin of the SVE (Galn & Herrera, 2005; Galn et al., 2004 a-c ; Carreo & Urbani, 2004; Carreo & Blanco, 2004) and also in short notes in publications such as the Bulletin of the South American Speleological Federation (FEALC; as in Prez & Carreo, 2004; Carreo et al., 2005; and Galn & Herrera, 2005). In parallel with these discoveries, several other smaller crevice caves were discovered by Venezuelan cavers (Carreo et al., 2002) on the Wei-Assipu Tepui, which is the “smaller sister” of Roraima and called also Roraimita (2,400 m a.s.l.). While Venezuelans documented caves on Aprada Tepui (Fig. 13), a Slovak team found shorter horizontal uvial active caves on the Kukenn Tepui in 2006 (Vlek & mda, 2007). Shortly aer the discovery of Cueva Ojos de Cristal, other caves were also described on the Chimant Massif (2,698 m a.s.l.). Although exploration of the mesetas of this massif commenced in the early 1990s (Briceo &Schubert, 1992 a, b ), these newly discovered caves were explored and documented between 2004 and 2007 by Venezuelan and Czech-Slovak speleological teams led by Charles Brewer-Caras. e Charles Brewer Cave (Cueva Charles Brewer) with its two gigantic branches measuring 4,800 metres was volumetrically the larg est quartzite cave in the world (Brewer-Caras, 2005 a ). e quadratic proles of its domes are typical for quartzite caves, and these are up to 100 m wide and up to 40 m high (Fig. 14). e volumes created in this manner are comparable with the biggest chambers in the limestone systems of Borneo, Viet nam and New Guinea (Owen, 2011). Several papers have been dedicated to this cave, and while most of these were published in prestigious speleological journals (mda et al., 2005 a-e ), some also appeared in popular-scientic literature (Audy et al., 2004; mda et al., 2004; Audy & mda, 2005 a, b ; mda &Brewer-Caras, 2005). A special monographic issue of the Bulletin of the Slovak Speleological Society (Spravodaj Slov enskej Speleologickej Spolonosti) has also been dedicated to this cave (mda et al., 2005 h ). Fig. 12: The main passage close to the entrance of Cueva Ojos de Cristal on Roraima Tepui. –


In addition to the Charles Brewer Cave, other relatively large caves were also discovered and documented on the Chimant Massif during both the 2007 expedition (Audy et al., 2008; mda et al., 2007; mda et al., 2008 a,b ; Vlek et al., 2008) and the 2009 expedition (Audy et al., 2010; Lnczos et al., 2009 a, b , 2010 a, b ; mda, 2009, 2010; mda et al., 2009, 2010 a-c ; Vlek & mda, 2009; Vlek et al., 2009 a–e ). e following new caves were also discovered and documented in the Chimant Massif during these two expeditions; Cueva Juliana (3.0 km long), Cueva Zuna (2.52 km long), Cueva Yanna (1.08 km long) and Cueva Colibr (4.0 km long). At the same time, a cave system 7.5 km long was formed by connecting the Cueva Charles Brewer and Cueva del Diablo caves. e Czech members of the 2007 expedition discovered and explored the 2.5 km long Sistema de las Araas, and this has been described by Audy & Tsler (2007), Audy (2008) and Brewer-Caras & Audy (2010). e last two expeditions in 2009 discovered the important Muchimuk Cave, which was connected to the previously discovered Cueva Colibr to form the Sistema Muchimuk–Colibr cave system. Its dimensions then were 8.0 km long with 160 m denivelation (mda, 2009). is cave system is genetically connected with Cueva Charles Brewer. Since results from the last survey show that the ends of their main passages are located just a few metres apart, the explorers led by Charles Brewer-Caras consider that all these caves are inter-connected in the one 17.8 km cave system (Audy et al., 2010; Brewer-Caras & Audy, 2010). is system has recently been distinguished as the largest quartzite cave system in the world. It has been epony mously named the Charles Brewer Cave System, and it contains the 400,000 m 3 Gran Galera Karen y Fanny, and with passages, in the Cueva Charles Brewer sector, averaging 30 60 metres as well. In 2009, the Italian La Venta team made two discoveries. One consisted of the new 3.5 km long corridors in Sistema Akopn – Dal Cin – Maripak located on the Akopn Tepui, which also forms part of the Chimant Massif. e second was the Cueva Auchimp on Chur Tepui (Cueva Eladio, 1 km long; De Vivo, 2009; La Venta, 2009; Mecchia et al., 2009). e Italian cavers in 2009 – 2010 also directed two expeditions to Auyn Tepui, where they explored the beautifully decorated 0.7 km long Cueva Guacamaya, andthe 0.3 km long Cueva del guila. ese were both very similar to the Cueva Charles Brewer, but smaller in size. An important and surprising discovery was made in 2006 on the Serra do Arac in the Brazilian part of the Guyana Highlands. is was the Abismo Guy Collet Cave and its 670.6 m depth made it the deepest quartzite cave in the world (Epis, 2006; Ayub 2007, 2008). Due to the currently accepted potential of quartzite massifs world-wide, we expect that this will remain the deepest known cave for quite some time. A new survey of the Cueva Ojos de Cristal extended the cave length to 16,140 m (mda et al., 2008 a, b ) andthe Charles Brewer Cave System was likewise revised to 17.8 km (Audy et al., 2010; Brewer-Caras & Audy, 2010). is laer revision created a new world record (Tab. 1). Research summary shows that approximately 50 speleologi cal expeditions have been so far conducted to the Venezuelan table-mountains. erein, 20 quartzite-karst areas were explored and documented, together with over 160 quartzite caves with a total length of 60 km (Vlek, 2010). . rf f – nfnr, n f Fig. 13: Giant entrance portal of Cueva El Fantasma on Aprada Tepui. Note the helicopters on the cave bottom. Fig.14 : The main passage in Cueva Charles Brewer branch, Charles Brewer Cave System.


2.3. CHARLES BREWER CAVE SYSTEM Localization: Chimant Massif, partial massif Chur Tepui Height a.s.l.: 2,100 m Length: 17.8 km (formed by several cave sectors connected to each other on the Chur Tepui (sensu Brewer-Caras & Audy, 2010). However, the caves over the collapses to the west of Cueva Charles Brewer and also caves to its south do not form part of this cave system). Depth: 160 m Exploration: 2003 – 2010 2.3.1. Introduction In 2002, Charles Brewer-Caras discovered an interesting de pression with an underground entrance on top of the Chimant Massif (Fig. 15). In the following year, the Grupo Espeleologico de Sociedad Venezolana de Ciencias Naturales (GE SVCN – e Speleological Group of the Venezuelan Society of Natural Sciences) organized a scientic expedition to this site under the supervision of the Comisin Nacional para la Proteccin de los Tepuyes (National Comission for the Protection of the Tepuis). e leader of this expedition was Charles Brewer-Caras, who organized the following team of Venezuelan scientists and cav ers; Charles Brewer-Capriles, Federico Mayoral, Alberto Tovar, Luis Alberto Carnicero, Fernando Tamayo, Alejandro Chuma ceiro, Eduardo Wallis, Alfredo Chacn, Ricardo Guerrero and – Tab. 1: List of tepuis’ quartzite caves longer than 1 km. number cave lenght (km) depth (m) localization state explorers 1 Charles Brewer Cave System 17.8 160 Chur Tepui, Estado Bolvar Venezuela Ch. Brewer-Caras, M. Audy, B. mda et al. (SSS, nSS, GE SVCN, 2004 – 2009) 2 Ojos de Cristal Cave System (Crystal Eyes Cave System, jaskynn systm Krytlov oi) 16.14 73 Roraima Tepui, Estado Bolvar Venezuela B. mda et al. (SSS, nSS, GE SVCN, SVE 2003 – 2007) 3 Sistema de las Araas 3.5 Chur Tepui, Estado Bolvar Venezuela M. Audy et al. (nSS, GE SVCN, 2007) 4 Sistema Akopn – Dal Cin – Maripak 3.5 Akopn Tepui, Estado Bolvar Venezuela La Venta, 2009 – 2010 5 Cueva Juliana 3.0 45 Chur Tepui, Estado Bolvar Venezuela B. mda et al. (SSS, GE SVCN, 2007 – 2009) 6 Sima Auyn Tepui Noroeste 2.95 370 Auyn Tepui, Estado Bolvar Venezuela F. Urbani et al. (SSI, SVE, 1996) 7 Sima Aonda Superior 2.128 362 Aonda Tepui, Estado Bolvar Venezuela F. Urbani et al. (SSI, SVE, 1996) 8 Sima Aonda 1.88 383 Aonda Tepui, Estado Bolvar Venezuela SVE (1983), SSI, SVE (1993 – 1996) 9 Sima Acopn 1 1.376 90 Akopn Tepui, Estado Bolvar Venezuela UEV, SVE (1993) 10 Sima de La Lluvia de Sarisariama 1.352 202 Sarisariama, Estado Bolvar Venezuela FPA, SVE (1976) 11 Sima Menor 1.158 248 Sarisariama, Estado Bolvar Venezuela FPA, SVE, GE SVCN (1976) 12 Cueva Yanna 1.08 40 Chur Tepui, Estado Bolvar Venezuela L. Vlek et al. (SSS, GE SVCN, 2009) 13 Sima Aonda 2 1.05 325 Aonda Tepui, Estado Bolvar Venezuela SSI, SVE (1993)


Francisco Delascio. Aer descending into the cave through the huge passage, they reached the rst lake near the Cascadas de las Araas waterfalls. Here, to their great astonishment they discovered the most amazing large quartzite cave. is cave, 4,482 m long and 110 m deep was eponymously named Cueva Charles Brewer. Several more expeditions led by Charles BrewerCaras followed, and he invited experienced cavers to join him. ese included Charles Brewer-Capriles, Federico Mayoral, Luis Alberto Carnicero and John Brewer together with Czech caver Marek Audy and the Slovak caver Branislav mda. Several scientic publications contained results from these expeditions (Audy et al., 2004; mda et al., 2004; mda & Brewer-Caras, 2005) and this unique research was highlighted in a special is sue of the Bulletin of the Slovak Speleological Society 3/2005 (mda et al., 2005 h ). Some of these studies met with criticism such as that from Urbani (2005), who had not explored this cave, and moreover, he had never visited it. Due to the many interesting discoveries, Charles Brewer-Caras organized several larger scientic expeditions, inviting additional members and scientists, not only from Venezuela (Federico Mayoral, Charles Brewer-Capriles, John Brewer, Roberto Brewer Martnez, Cesar Barrio-Amors, Vicente Capriles, Hernn Biord, Luis Alberto Carnicero, Juan Carlos Godayol, Robert Cristobal, Francisco Delascio Chiy, Vincente Marcano, Roberto Brewer Mendoza, Francisco Delascio Chiy, Robert Rafael Eraso, Javier Mesa and Ben Williams), but also from other countries including Slovakia (Branislav mda, Marin Majerk, Erik Kapucian, Marcel Grik, Zdenko Hochmuth, Jn Pavlk andPavol Barab), and the Czech Republic (Marek Audy and Richard Bouda). e 2005 expedition discovered several new caves in the area near Cueva Charles Brewer. ese included the 2.3 km long Cueva del Diablo, the 0.8 km long Cueva del Caon Verde, and the 170 m deep Sima Noroeste. A sketch of the cave outlay taken from an aerial-view is shown in Fig. 16. Deeper explorations into Cueva Charles Brewer and Cueva del Diablo revealed additional spec tacular discoveries including interconnections with a branch of Gran Galera de los Gucharos which increased the cave length by several hundred metres, to a total length of 4.8 km (Audy & mda, 2005 a, b ; Barab, 2006; Brewer-Caras, 2005 a, b ; mda et al. 2005 a-h ). Many results from this expedition were widely popularized by the following researchers; Chacn et al. (2006); Chiappe (2006 a, b ); Marbach & Fage (2006); Mayoral (2006); Hernandez (2005); Palmitesta Riveros (2006 a-c ); Ramos Zibert (2006); Snchez & Carnicero (2005); and mda et al. (2005 a, b, c ). A further expedition was organized in 2007 by the follow ing speleologists; Branislav mda, Zoltn gh, Erik Kapucian andLuk Vlek from Slovakia, Marek Audy, Richard Bouda andRadko Tsler of the Czech Republic, Mladen Kuhta andRob ert Dado from Croatia, and the Venezuelans Federico Mayoral and Igor Elorza. In addition to these, several other experts joined Fig. 15: Aerial view to Chur Tepui from the northeast. . rf f – nfnr, n f


this team. ese included Roman Aubrecht, Tom Lnczos andJn Schlgl from the geological-geochemical team at the Comenius University in Slovakia, the Spanish herpetologist Ce sar Barrio-Amors and also a group consisting of Charles BrewerCaras with a BBC lm crew led by Roger Santo Domingo and Ian James representing the American Press. e aim of this expedition was to explore the northern part of Chur Tepui. is succeeded beyond expectation when several new caves were dis covered on the Chur Tepui plateau. ese supplemented those observed during a helicopter ight by Charles Brewer-Caras the previous year. e newly discovered caves were: Cueva de la Araa – Cueva la Cortina (2.5 km long), Cueva el Diente – Puente de Diana Cave (0.05 km long), Cueva Bautismo del Fuego (0.4 km long), Cueva Juliana (1 km long), Cueva Tetris (0.15 km long), Cueva Croatia (0.1 – 0.2 km long), Cueva Zuna (0.31 km long), Cueva con Columnas (0.2 km long), plus the Cueva Eladio and Cueva Colibr which were merely observed from helicopter. All of these caves constitute dierent parts of a complicated cave system located parallel to Cueva Charles Brewer and west of its main passage. However, these are all isolated by dierent types of rock collapses of pre-existing cave ceilings. e results of these expeditions were described in several publications (Aubrecht et al., 2008 a, b ; Audy et al., 2008; Barrio-Amors et al., 2010; Lnczos et al., 2009 a, b , 2010 a, b ; mda et al., 2007, 2008 a-c ; Vlek et al., 2008, 2009 a-e ). Some caves in this area, and particularly Cueva Auchimp, which is currently known as the Cueva Eladio, were also explored by other caving expeditions in parallel with the above expeditions. A contemporaneous example is the La Venta expedition noted on web link hp:// Several expeditions explored the Chur Tepui plateau in 2009. ese expeditions were organized by collaborating teams: a Slovak speleological team (Branislav mda, Erik Kapucian, Luk Vlek, Jaroslav Stankovi andViliam Guta), a general scientic team from the Slovak Comenius University (Roman Aubrecht, Jn Schlgl, Tom Lnczos and Tom Derka), a Croatian caver team (Darko Bakib and Ana Bakib) and the Venezuelan caver Javier Mesa. e tasks of the speleological team were to land on the north ern part of the meseta and reach the area expected for the logical continuation of Cueva Charles Brewer. Although some intended research could not be carried out as initially planned, this team made the following important discoveries; i) the junction be tween Cueva Charles Brewer andCueva del Diablo was mapped, so that the total length of the system was extended to 7.5 km; ii) two caves were discovered to be longer than previously believed: Cueva Zuna with 2.52 km total length and Cueva Juliana with 3 km; iii) several new caves were discovered including the 0.2 – 0.3 km long Cueva de dos Machetes, the 1.08 km long Cueva Yanna and the 4.6 km long Cueva Colibr. e most important of these is the giant Cueva Colibr located in the northern part of the tepui. Since the water in the cave stream ows from the northern edge of the tepui southerly towards the Cueva Charles Brewer area, there was a distinct possibility that these two caves are joined. Fig. 16: Speleological sketch of the Charles Brewer Cave System and adjacent caves. –


Further evidence for this theory was obtained during the next expedition to Cueva Eladio by the team of Branislav mda, Marcel Grik, Charles Brewer-Caras, Federico Mayoral, Marek Audy, Richard Bouda, Pavol Barab and Ben Williams. In this expedition, another connecting giant cave was discovered that extended the Cueva Colibr into the 8 km Cueva Muchimuk – Cueva Colibr Cave System (Audy & Brewer-Caras, 2009; mda 2009, 2010; mda et al. 2009, 2010 a-c ; Vlek & mda, 2009). Although a physical connection with the Cueva Charles Brewer was not possible because the southern end of this cave ended in a huge cave-fall (mda et al. 2010 c ), topographically, this cave-fall appears identical to the one at the end of Cueva Charles Brewer. erefore, Audy et al. (2010) and Brewer-Caras & Audy (2010) inferred that these caves should be regarded as one cave system. is particular cave-fall was thereupon inserted into a detailed map published by Audy et al. (2010). Aer these expeditions, the total length of the cave system named Sistema Muchimuk; sensu Audy et al. (2010) or Sistema Charles Brewer; sensu Brewer-Caras & Audy (2010), was registered at 17.8 km (30 m). Herein, it is referred to as the Charles Brewer Cave System, and this is cur rently recognized as the longest and most voluminous quartzite cave system in the world (Hernandez, 2010). However, these observations and conclusions are not indisputable. For example, mda (2010), mda & Vlek (2010) and mda et al. (2009, 2010 a-c ) did not accept this junction, because not all interconnec tions had been physically proven. erefore the maps and papers of mda & Vlek (2010) and mda et al. (2010 a-c ) present the Muchimuk – Colibr Cave as 8 km long and the Sistema Charles Brewer – Cueva del Diablo as 7.5 km long. e expedition also surveyed Cueva Eladio, which had been visited the previous year by Italian cavers who named it Cueva Auchimp (Mecchia et al., 2009). According to research by Audy et al. (2010) andBrewerCaras & Audy (2010), the 4 km m Cueva de las Araas Cave System was created by the physical junction of the following three caves: Cueva Cortina, Cueva de la Araa andCueva Eladio. Numerous scientic results and new biological research re sulted from all expeditions, including those undertaken by Audy & Kalenda, 2010; Breure & Schlgl (2010); Derka & Fedor (2010); Derka et al. (2009, 2010); Robovsk et al. (2007), and popular reports on this huge cave system on Chimant were published by Ochoia Breijo (2011) and Rodrgues (2011). Two additional expeditions were organized independently in 2009; i) by the Italian team (Corrado Conca, Tono De Vivo, Marco Mecchia, Francesco Sauro, Rolando Menardi, Fabio Negroni, Alessio Romeo, Pier Paolo Porcu, Andrea Pasqualini, Carla Corongiu, Viorio Crobu; De Vivo – see La Venta, 2009; Mecchia et al., 2009); and ii) by the Venezuelan scientic-caver team led by Charles Brewer-Caras accompanied by scientists from Canada, U.S.A. and Austria (Lundberg et al., 2010 a, b ). 2.3.2. Localization e reported cave system is located in the Chimant group of table-mountains, close to the northern edge of the Chur Tepui (2,100 m a.s.l.) (Fig. 16). Entrances to the cave system are situ ated between the middle of the central valley which divides the mountain into two parts, and the northern edge of the meseta. e main entrance forms the mouth of the discharge passage of the cave, draining most of the cave system’s accumulated water from the northern and the central parts of the mountain. Other independent watercourses are distributed within the cave. e delta-like Cueva Muchimuk – Cueva Charles Brewer branches are situated north of these streams, while an underground wa tercourse ows parallel to these branches through the independ ent Cueva Eladio and Cueva de las Araas. To the south, this ows through parts of the Charles Brewer Cave System (Cueva del Diablo andCueva Zuna). Underground watercourses also ow through the separate Cueva Juliana andCueva Yanna on a level below and to the south of the studied cave system. Along this path, the Charles Brewer Cave System splits into the spa tially and genetically distinct sectors of Cueva Zuna, Cueva del Diablo, Cueva Charles Brewer, Cueva Muchimuk andCueva Colibr. Other caves which clearly form one genetic system are located in the vicinity (Fig. 16). All the above mentioned caves are situated relatively close to the surface. Following the gradual elevation of the terrain to the north, the southern sectors such as Cueva Zuna and the entrance to the Cueva Charles Brewer are only 50 – 80 m below the surface of the plateau, while the more northern cave parts are 100 – 120 m under it. Altogether, the cave system has 18 entrances; (1) 5 of these are in the north ern wall of the Chur Tepui and 2 in the Colibr Depression, forming the 7 entrances of the Colibr sector; (2) 1 enters the Cueva Muchimuk sector from the south; (3) there is the main entrance situated in the Charles Brewer Depression; (4) 1 enters Fig. 17: Entrance to the Cueva Zuna sector in the Zuna Depression. . rf f – nfnr, n f


Fig. 18: Interior of the 120 m wide entrance to the Cueva Charles Brewer sector, previously an independent cave. Fig. 19: Passage in the Gucharo branch, Cueva Charles Brewer sector. –


the Cueva Charles Brewer sector and a 2nd enters the Cueva del Diablo sector from the Gucharo Depression; (5) the Cueva del Diablo sector has two entrances situated in depressions dividing the partial massifs of rock towers east of the central valley, and referred to as the Diablo Depression; and (6) the Cueva Zuna sector has two entrances from the Charles Brewer Depression together with two from the Zuna Depression and one from the Diablo Depression. 2.3.3. Charles Brewer Cave System: basic description Cueva Zuna e Cueva Zuna sector has two entrances into the so-called Zuna South part from the Charles Brewer collapse depression, but these are partly blocked by stony debris. ese passages then continue upstream to the north as two parallel branches connected by a labyrinth of side-branches until they end in the entrances of the Zuna Depression (Fig. 17). Meanwhile, the Zuna North entrance is in the opposite wall of the collapse depression. e Zuna North cave portion involves two adjoined branches which eventually form the surface opening of the Diablo De pression, which was previously called the Bromelia Vertical Cave. Part of the Cueva Zuna sector is situated only 50 – 60 m below the surface, and this has passages 1.5–2.5 m high and 2–5 m width. e Cueva Zuna is approximately 2.8 km long and it forms a continuation of the Cueva del Diablo through the Diablo Depression. Cueva del Diablo e Cueva del Diablo sector is formed by two spacious horizontal corridors opening onto the surface in several vertical crevices. ese crevices cut the towers of the rock town, east of the Chur Tepui central valley. e Diablo North cave portion runs to the north and ends in rugged terrain between the towers south of Cueva del Caon Verde, Cueva Croatia and Cueva Bautismo del Fuego. e direction of the Cueva Diablo South is southeast, and this opens into the Gucharo Depression through a rock-fall. is depression was formed by a ceiling collapse in a former huge cave passage which now separates the Cueva del Diablo sector from the Gran Galera de los Gucharos passage in the Cueva Charles Brewer sector. is sector’s underground area is relatively supercial, at up to 100 m, with an average corridor height of 10 m and an average width of 30 m. e total length of the Cueva del Diablo sector is approximately 3 km. Cueva Charles Brewer e Cueva Charles Brewer sector has two entrances, with the dimensions of the main entrance, Boca de Mamut (the Mam moth’s Mouth) 120 15 – 30 m (Fig. 18). is entrance is situ ated in the Charles Brewer Depression behind a huge rockfall formed by a cave ceiling collapse. is divides the cave here into two separate branches. One of these is the Gucharo branch (Gran Galera de los Gucharos), which runs northwest as a continuation of the Cueva del Diablo sector. e dimensions of the passage are up to 50 m in height and 80 m in width (Fig. 19). . rf f – nfnr, n f Fig. 20: An average corridor in the main passage of the Cueva Charles Brewer sector.


e second branch runs northeast against the stream ow direc tion and forms a simple, but huge, slightly meandering corridor leading into the massif. e average dimensions of this corridor are 40 15 m, with width approaching 80–100 m and height approaching 40 m (Fig. 20). ere are several large chambers in this area with the largest of them named Gran Galera Karen y Fanny. is has a total volume of 400,000 m 3 , which makes it one of the largest underground spaces in the world (mda et al., 2005 h ). Aer 2 km, the corridor is divided into two branches, and both end in cave-falls, with a river discharging from them. e cave system then continues past these cave-falls into the Cueva Muchimuk sector. e total length of the Cueva Charles Brewer sector is 4.5 km. Cueva Muchimuk e entrance to Cueva Muchimuk is located in the vast Colibr Depression at the northern part of the mountain. e cave runs in a southerly direction along the underground river, ending in the cave-fall which connects this cave to the Cueva Charles Brewer sector. Cueva Muchimuk divides into 4 huge corridors lateral to Cueva de las Araas west of the area, close to Sima Noroeste. e streams in the corridors originate from the Colibr Depression and join together as an underground river opening into a cave-fall at the end of the cave. e width of the corridors ranges between 20–50 m, and their height between 8 – 15 m (Fig. 21). e 4 km long Cueva Muchimuk sector is connected at its northern end to the Cueva Colibr sector by a 120 m deep Colibr Depression (Fig. 22). Fig. 21: A corridor in the main passage of the Cueva Muchimuk sector. Fig. 22: Entrance to the Cueva Colibr sector in the 120 m deep Colibr Depression. –

PAGE 28 Cueva Colibr e Cueva Colibr sector forms a complicated two-dimensional labyrinth of an anastomousing corridor network that converges from the northern edge of the plateau into three cave branches. ese branches are the Gran Galera de el Jaguar – Galera Yunek, Galera Ana – Renata andGalera Lagos y Cataratas de nertk– Helen. e width of their corridors ranges between 20 m and 40 m and their height 8–15 m, with a most usual corridor size of approximately 20 m 8 m (Fig. 23). ey open into the Colibr Depression (grieta), east of the entrance of the Cueva Eladio (Fig. 22). ey have smaller side passages and are well watered by small streams. Five parallel entrances open on the northern wall of the tepui. e length of this sector is 3.5 km. 2.3.4. Cave spatial framework e spatial framework of the cave systems on Chur Tepui shares similar geological paerns to Cueva Ojos de Cristal on the Mt. Roraima, and it follows the same principles as “classical” karst phenomena (mda et al. 2003). A crucial dierence here is the anastomosing labyrinth of passages which converge into one large drainage pipeline characteristic of Chur Tepui caves, while the cave architecture on Roraima Mountain remains the same to its adit. We therefore presume that the Cueva Ojos de Cristal is in an earlier stage of evolution than the older and more spa cious Charles Brewer Cave System. Water owing through the cave areas drains into them through vertical seepages along the crevices and grietas or by horizontal seepages along the bedding planes which dip to the southeast. e anastomosing corridor network forming the Cueva Colibr sector is located in the area of the Colibr Depression, then the network merges into two large draining branches of the Cueva Muchimuk sector. ese then merge into one giant tube passing over the huge cave rockfall to the Cueva Charles Brewer sector. It is obvious that more of these large underground drainage systems must have existed on Chur Tepui in earlier times. is was proven by the discovery of a parallel cave system continuing in a southerly direction. is system included the following: Cueva Eladio–Cueva de las Araas (which is considered one cave, Sistema de las Araas), Cueva del Caon Verde, Cueva del Diablo sector, Cueva Zuna sector, andthe Gucharo branch of the Cueva Charles Brewer sector. Although these caves dier spatially, they form one drain age system. It is most likely that in the past they formed one continuous cave system, but today they are divided by huge collapses (Fig. 24). e largest collapse zone is located in a dis charge zone between the systems which lie south of the Cueva Charles Brewer and Cueva Zuna sectors. We presume that a huge quartzite cave occurred here, and that it was most likely one of the largest of its kind in geological history until destroyed by reverse erosion of rivers owing from the cave entrances. Today, the draining of the central part of the massif of the Chur Tepui continues a level below the Cueva Charles Brewer, as indicted . rf f – nfnr, n f Fig. 23: One of the passages in the Cueva Colibr sector.


by young cave channels of Cueva Juliana and Cueva Yanna, situated approximately 60 m beneath the Cueva Charles Brewer opening. ese caves possess considerably smaller corridors which strongly resemble the Cueva Ojos de Cristal passages on the Roraima Tepui. 2.3.5. Speleological perspectives Since the speleological explorations undertaken until now have focused only on the central part of the massif, the remaining mountain underground is still less explored. Only the zone be tween Cueva Colibr in the north and Cueva Juliana in the south has been relatively well documented in this area. e remainder, including a plateau with deep crevices, still awaits exploration, and we envisage that most of these unexplored areas will provide many interesting geological insights. One such area lies between the Cueva del Diablo and Cueva Charles Brewer sectors. Here, we postulate the existence of more than one huge cave branch which could form a lateral continuation of long passages into the Cueva Muchimuk sector far to the east and to Galera con 100 Lagos. In addition, Cueva Juliana andCueva Yanna, which lie at the lowest depths, have not been completely explored to the ends of their passages. When considering the caves’ spatial structure and the denseness of their occurrence, it is obvious that the speleological potential of the Chur Tepui is far from entirely exploited. Further speleological investigation should unveil many further astound ing discoveries, such as kilometres, or even tens of kilometres of additional passages. ere is also great potential to discover many other interesting phenomena in this territory which will greatly stimulate many research areas, especially in the areas of geochemistry, mineralogy, hydrochemistry and geobiology. 2.4. OJOS DE CRISTAL CAVE SYSTEM Localization: Roraima Tepui Height above a.s.l.: 2,630 m Length: 16.14 km Depth: 73 m Exploration: 2002 – 2007 Fig. 24: Descent to the blocked area near Cueva Caon Verde. –


2.4.1. Introduction During 2002 two cavers, Zoltn gh of the Slovak Speleological Society and Marek Audy from the Czech Speleological Society, discovered an inconspicuous entrance to an inlet cave on the Roraima Tepui (Fig. 25). Since they lacked equipment required for more extensive exploration, they were only able to reach a horizontal passage approximately 300 m into an area with a lowered passage prole. is site was quite inaccessible and demanded tedious crawling for further advance. Since this cave contained numerous pot-holes on the oor, lled with rounded quartz crystals, it was named “Cueva Ojos de Cristal” (Crystal Eyes Cave, Jaskya krytlovch o). Compared to previous descriptions of quartzite caves in other parts of the world, this cave proved to be quite unique, due to its unusual parent rocks and its horizontal course. Previously described quartzite caves were mainly characterized by deep vertical crevices which nor mally obtained water from the mountain surface, with this water then draining into external springs through the vertical outer mountain walls. Moreover, since this cave is situated close to the southern edge of the meseta and the cave water ows from south to north, there is at least the theoretical possibility of the existence of a cave traversing the entire mountain and ending at the springs situated in the northern walls of tepui. A short Slovakian-Czech speleological expedition to the Ro raima Tepui was organized in 2003 to explore this notion. e members of this group were Branislav mda, Erik Kapucian, Marcel Grik, Luk Vlek, Marek Audy, Zoltn gh and Marin Majerk, and they had Venezuelan guides led by Antonio Jos Arocha Gonzales. During this week-long expedition, the cavers explored not only the Cueva Ojos de Cristal in greater detail, they also mapped 3.5 km of underground passages in the following 15 caves connected to this area; Cueva debajo del Hotel Principal, Cueva Asxiadora, Cueva de Gilberto, Cueva Fragmento Mar ginal, Cueva con Bloques de Piedra, Cueva del Hotel Gucharos, Cueva 007, Cueva Papua, Cueva con Cataratita, Cueva 009, Gri eta de Diablitos Volantes, Cueva con Puente, Cueva de Araas Hidrlas, Cueva Hipottica, Tun Deut, and Cueva El Foso. Fluvial corridors in the water ow direction in Cueva Ojos de Cristal measured an astonishing total length of 2.41 km. It had an elevation of 24 m, and contained an underground anastomosing passage system (Fig. 26) where the passages converged at the main water outow in the vertical crevice. is particular site is named Pokmon (mda et al., 2003). ese ndings, together with the fact that this cave is characterized by a rather unique relatively horizontal direction, clearly suggested that Cueva Ojos de Cristal represented a new morphogenetic quartzite cave type, and also that it is one of the most prominent large quartzite caves in the world (for general scientic descriptions, see Audy, 2003, 2008; Audy & mda, 2003; Vlek, 2004; for a general overview see the special monographic issue of the Bulletin of the Slovak Speleologi cal Society by mda et al., 2003). is discovery evoked heated debates about its legitimacy in several associations, including the International Union of Speleology – UIS and the Speleological . rf f – nfnr, n f Fig. 25: View of the southern wall of Roraima Tepui from the ascent path, highlighting the highest point of El Maverick at 2,889 m a.s.l.


Federation of Latin America and the Caribbean – FEALC (see Geospeleology Commission of FEALC Newsleer – No. 60). However, the Czech-Slovak team gained respect thanks to ex pedition led by Charles Brewer-Caras to Cueva Charles Brewer on the Chimant Massif in 2004. Marek Audy and Branislav mda also accompanied this expedition. is expedition then initiated fruitful cooperation between the Czech-Slovak and Venezuelan cavers associated in Grupo Espeleologico de Sociedad Venezolana de Ciencias Naturales – GESVCN. Another large cave, with 4,482 m length and 110 m denivelation, was discovered on this expedition to the Chimant Massif, thus surpassing the acknowledged length of Cueva Ojos de Cristal (see Chapter 2.3.). Another Venezuelan-Czecho-Slovakian expedition was or ganized in 2005 by Charles Brewer-Caras, Federico Mayoral, Branislav mda, Marek Audy, and others. e goal of this ex pedition was to further investigate both Cueva Charles Brewer and Cueva Ojos de Cristal. Exploration of Cueva Ojos de Cristal was undertaken by the smaller team of Branislav mda, Erik Kapucian, Marcel Grik andMarin Majerk. ey claried the cave’s continuation over the Pokmon crevice, and then recorded the length of the nearby Cueva de los Pmones at an astonishing 5.3 km. ese results from the Chimant Massif were published in several papers (mda et al., 2005 a-e ; mda et al., 2004; Audy & mda, 2005 a, b ; mda &Brewer-Caras, 2005), and in a special monographic issue of the Bulletin of the Slovak Speleological Society dedicated to these discoveries on the Chimant Massif (mda et al., 2005 h ). is edition was published in both Slovak and Spanish languages. Exploration results from Cueva Ojos de Cristal have been published in papers by mda et al. (2005 a, b ). Cueva Ojos de Cristal was renamed Sistema Roraima Sur by the Venezuelan-British-Spanish team in 2004. During their 2004 and 2005 expeditions, this team also remapped the Cueva Ojos de Cristal Cave, and measured extensions of the Cueva de los Pmones passages at 10.82 km. Since the map published by this team contains some discrepancies, this caused confusion. For example, Young et al. (2009) unfortunately dened Sistema Roraima Sur and Cueva Ojos de Cristal as being two dierent caves. For completely reliable tracking of the order of events and the cave descriptions, please see the monographic issue of the Boletn de la Sociedad Venezolana de Espeleologa (SVE) in 2005 (this issue was antedated to 2004; Galn et al., 2004 a-b ; Carreo & Urbani, 2004; Carreo & Blanco, 2004). Shorter notes are also contained in scientic papers by Galn & Herrera (2005); Prez & Carreo (2004); Carreo et al. (2005); Galn & Herrera (2006), and Barton et al. (2009). Fig. 26: Schematic speleological groundplan of the Ojos de Cristal Cave System. E –entrances, with numbers indicating the number of entrances when several are close to each other. –


A new expedition was organized to Kukenn andRoraima tepuis in 2006 to sele various disputes. is was undertak en by the Slovak cavers, Branislav mda, Luk Vlek, Peter Medzihradsk, Jozef Ondruka, Peter Masarovi andPavol Barab. ey explored a few of short horizontal caves and de scended to the Sima Kukenn scha. Aer this, the group was divided into two parts on Roraima Tepui for detailed studies of Cueva del los Pmones andCueva Ojos de Cristal. is led to the discovery and survey of several passages which increased the total length of the cave system to 15.28 km. Several interesting cave connections were discovered. e main was the intercon nection of the above mentioned two caves through the Cueva del Hotel Gucharos, and the second was the discovery that Cueva del Gilberto andCueva Asxiadora were physically connected to this large cave system. e results of this expedition were published by Vlek &mda (2007), and also in a documentary movie called Matau (Barab, 2007). Aer the expedition to Chimant Massif, a Slovak-CroatianVenezuelan expedition to Roraima was organized in 2007 by the cavers Branislav mda, Luk Vlek, Erik Kapucian, Zoltn gh, Igor Elorza, Mladen Kuhta and Robert Dado. ey also invited a Slovak scientic team from the Comenius University in Bratislava consisting of Roman Aubrecht, Tom Lnczos and Jn Schlgl. During this expedition, interconnections of Cueva Ojos de Cristal with Cueva de Gilberto (including the former independent Fragmento Marginal Cave) and with Cueva Asxi adora were discovered, thus the total lenght of the Cueva Ojos de Cristal was nally registered at 16.14 km with a denivelation of 73 m (mda et al., 2007, 2008 a-d ; Vlek et al., 2008). A further expedition was specially organized by Slovak and Croatian cavers, comprising Slovak cavers and scientists, Luk Vlek, Viliam Guta, Jn Schlgl and Tom Derka and the Croa tian cavers Darko and Ana Bakib. Its main goals were to visit Roraima and Cueva Ojos de Cristal and to take samples for scientic research (mda, 2010; Vlek & mda, 2009; Vlek et al., 2009 a-c ). e summary of current discoveries and their status in the history of cave explorations read as follows; the 16.14 km length established in 2006 for Cueva Ojos de Cristal surpassed the length of the limestone Cueva el Samn located in the neighbour ing state of Zulia, and thus became the longest cave discovered in Venezuela. However, the prolonged mapping of Cueva el Samn completed by Venezuelan cavers the following year reversed this, and Cueva el Samn was re-established as the longest cave at 18.2 km (Herrera et al., 2006). Since a complete detailed map of Cueva Ojos de Cristal has not yet been published, its total length is still debatable; as in Audy (2008), and Brewer-Caras & Audy (2010). . rf f – nfnr, n f Fig. 27: Ponor depression of Cueva Ojos de Cristal, where the cave was discovered.


2.4.2. Localization Cueva de Ojos de Cristal is situated on the Roraima table moun tain at 2,810 m a.s.l. close to its southern edge. e entrance which was discovered rst, is located at one of the southern most parts of the entire cave system (Fig. 27). It is formed by a sinkhole draining rainwater from an approximately 0.02 km 2 wide area, so that underground streams form several cave pas sages. Genetic aspects play an important role in discoveries of distinct parts of this system, so from a speleogenetic viewpoint this cave can be divided into ve dierent sectors: Cueva Ojos de Cristal, Cueva Mischel, Cueva del Hotel Gucharos, Cueva de los Pmones, and Cueva Asxiadora with Cueva de Gilberto. Based on current discoveries, this cave has the following 23 entrances; 4 situated in the sink depression of the Cueva Ojos de Cristal; 5 in the outer wall of the Roraima Tepui at depths of up to 70 m below the plateau; 2 in the sink depression of the Cueva Mischel; 6 in two sink depressions of Cueva Asxiadora andCueva de Gilberto; 1 forming the huge portal of the Hotel Gucharos rock shelter; and the nal 5 discovered on the vertical crevices named Pokmons, whose basal portions are connected to deep horizontal passages. Fig. 28: Entrance to the Cueva Mischel sector – previously the independent Cueva Mischel. Fig. 29: The main passage of the Cueva Ojos de Cristal sector. –


2.4.3. Ojos de Cristal Cave System – basic description Cueva Mischel e Cueva Mischel sector begins as two sink entrances located in a huge at-based sink depression which drains rainwater from a surrounding 0.05 km 2 area. e underground drainage ow direction is westward from this depression. Two entrances are situated under the western edge; a northern one among rock towers and a southern one which appears to form a visible sink entrance into compact rock (Fig. 28). e stream divides into two parts which sink into the massif and ow to the northwest, where they join again. Aer 100 metres, this cave sector joins Cueva Ojos de Cristal sector, this part of the cave is approx. 1 km long. e Cueva Mischel/Cueva Ojos de Cristal intercon nection was surveyed in 2003, as reported in mda et al. (2003). Cueva Ojos de Cristal e Cueva Ojos de Cristal sector begins in the Ojos de Cristal sink depression in a surrounding area of approximately 0.02 km 2 . Here, four sink entrances enter the underground passages. ese generally run northerly with an inclination up to 5 degrees, and following the direction of the bedding plane dip. e cave termi nates approximately 300 m from the entrance at its junction with the 30 m deep Pokmon 1 vertical crevice, which opens in the rock elevation north of the entrance. Water from the sinks ows north wards disappearing between the blocks in the base of Pokmon 1, and during high water levels as occurs in the rainy season, it also dissipates through horizontal apertures in the pokmon’s base. e seeping water formed two conuent branches which owed from the cave in a south-westerly direction. One of these is now dry, while the other remains an active stream (Fig. 29). ese branches are connected to the Cueva Mischel sector. is sector is approximately 4 km long. A lateral horizontal corridor uniting Cueva Ojos de Cristal and Cueva del Hotel Gucharos deviates from the mid-section of these branches. e cave con nections here were surveyed in 2005 by mda et al., (2005 a-c ). Cueva del Hotel Gucharos e Cueva del Hotel Gucharos sector begins with a huge 50 m wide entrance with a maxiumum height of 5 m (Fig. 30). is entrance is generally used as a rock shelter by tourists and it therefore earned the nickname “hotel”, similarly as other rock shelters on Roraima Mt. Although this huge cave entrance has been frequently used for a long time, the rst scientic reports about it were not published before 2003 (mda et al., 2003). e cave continues from the entrance along declining quartz ite strata to a dry passage-way. Aer a distance of approximate ly 150 m, it connects with the Sala Con Catarata Dome (Wa terfall Hall). is waterfall is formed by a stream owing from an aperture throughout length of the ceiling. An eastern hori zontal branch from the Cueva Ojos de Cristal sector connects to the main watercourse immediately above this hall, and the . rf f – nfnr, n f Fig. 30: Entrance to the Cueva del Hotel Gucharos sector – previously the independent Cueva del Hotel Gucharos.


cave then continues as an active uvial branch in a low passage along the watercourse. Aer extreme narrowing in its north ernmost tip, the cave system continues into the Cueva de los Pmones sector. Although this narrow passage had previously been ploed by Venezuelan cavers in their 2005 map (Galn et al., 2004 a ), this connection was physically explored for the rst time by the members of the Slovak expedition in 2006 only (Vlek & mda, 2007). e Cueva del Hotel Gucharos sec tor is approximately 1 km long. Cueva de los Pmones e water from Cueva del Hotel Gucharos aer its narrowing continues in a slightly declining, low passage toward the verti cal 30 m deep Pokmon 2 crevice. e Cueva de los Pmones sector was rst discovered at this site. An extensive branch with up to 30 m wide corridors, like the Sala de la Madre Sociedad Espeleolgico de Eslovaqua, proceeds from this pokmon in a southerly to south-westerly direction against the ow of the stream which forms by water dripping down the cave walls. is branch ends in the southern wall of the tepui as a huge window which forms the southernmost of the ve entrances to the Cueva Ojos de Cristal Cave System which are situated be low the entrance of the Cueva del Hotel Gucharos sector. e stream ows in a northerly direction from Pokmon 2, which is actually a genetic continuation of Pokmon 1. e stream then reaches the Pokmon 3 vertical crevice (Fig. 31). e cave turns west – northwest above this pokmon before striking o in an easterly direction via low passages which are most likely con nected to the higher situated Cueva con Bloques de Piedra and Fig. 31: Descent into the Cueva de los Pmones sector through the vertical crevice Pokmon No. 3. – Fig. 32: The main passage in the Cueva de los Pmones sector.


related crevices penetrating from the surface. Two extensive di viding branches run from the main thrust and end in the walls of the Roraima Mt. Cueva de Gilberto is situated above the labyrinth in this part of the cave sector, and is connected to the system through a crevice. An underground stream ows below the main thrust and parallel to it. is stream is fed by the above mentioned branches, and it forms a huge corridor (Fig. 32) end ing in two rocky windows in the Roraima wall. A connecting branch from Cueva Asxiadora occurs above a vertical step ap proximately 100 m from the end of this sector. is connection was discovered in 2006 (Vlek & mda, 2007). During high water level events, as occur in the rainy season, the river owing through the Cueva de los Pmones makes impressive waterfalls ooding from a window in the wall. e total length of this most extensive sector of the Cueva Ojos de Cristal System is 8 km. Cueva Asxiadora and Cueva de Gilberto e Cueva Asxiadora and Cueva de Gilberto sector is located just above the Cueva de los Pmones section and forms an upper oor of the Ojos de Crystal Cave System. is sector is formed by three parts previously considered to be individual caves: Cueva de Gilberto, Cueva Asxiadora and Fragmento Marginal (mda et al., 2003). ese caves are connected by a 40 m 70 m collapse depression. Cueva de Gilberto drains part of the sink depres sion located south of the cave. is cave has four big entrances, all of which are suitable for underground camps (Fig. 33). e extensive Cueva de Gilberto has a complicated spatial arrange ment connected to the Fragmento Marginal and Cueva de los Pmones. Cueva de Gilberto is located at the western edge of the collapse depression which limits continuation of its underground passages, while Cueva Asxiadora has an entrance at the eastern edge of the depression, and this continues underground. is cave part is formed by a simple horizontal passage that ends in a sha leading to the lower oor of the cave system. is connec tion was surveyed in 2007 (Vlek & mda, 2007), and the total length of Cueva Asxiadora, Cueva de Gilberto and Fragmento Marginal sector passages was recorded at approximately 2 km. 2.4.4. Cave spatial framework e rst discovered entrance to the cave system is located at the southernmost part of the cave system. It is formed by a sink hole draining rainwater from the Ojos de Cristal sink depression. e water is then drained into underground streams which form various ngerlike passages connected to each other, all coursing toward the outow. In the geological past, the sink was drained . rf f – nfnr, n f Fig. 33: One of the entrances to the Cueva de Gilberto sector – previously the independent Cueva de Gilberto Cave.


by the now dry Cueva del Hotel Gucharo branch which was located superiorly. e Ojos de Cristal Cave System forms a supercial cave with passages running parallel to the sandstone strata of the Matau Formation. It also has slight declination to the north – northwest, in keeping with the 75 m cave declination to the deepest north-western part of the system at approximately 150 m below the plateau surface. e ground-plan indicates that this cave can be categorized as an anastomosing system, similar to karstic maze caves as in Palmer (1991). e largest passages in systems such as this act as water-ow corridors, and the smaller side passages, which aremostly at-shaped with sandy oors, only become uvial during extreme inow events (Fig. 34). Based on currently retrieved data and observations, we postulate that the most important parameters in the speleogenesis of these caves are the high energy storm waters which widen the cave system laterally into parallel channels and later connect the main corridors. Nine main corridors have been currently observed in this system. One of these forms a framework which delimits the Cueva Mischel sector from the north-east. Two other corridors form the framework of the Cueva Ojos de Cristal sector while another constitutes the Cueva del Hotel Gucharos sector, and four more compose the main thrust of the Cueva de los Pmones. e last corridor is mostly dry, and it runs through the Cueva Asxiadora and Cueva de Gilberto sectors. e vertical part of the cave system – the so-called pokmons – act as a rapid water supply to the cavern underground. Although they normally drain small areas, Pokmon 2 drains a larger part of the sink depression south of Cueva del Gilberto from a surrounding area of approximately 0.025 km 2 . e vertical crevices also act as expansion basins which can accumulate excess inow during the high water level events. e pokmons and whole Cueva Ojos de Cristal Cave System can be considered as supercial karst phenomena, reaching only a few tens of metres below the tepui surface. Deeper structures are represented by grietas. 2.4.5. Speleological perspectives Although ve expeditions were undertaken to the Ojos de Cristal Cave System, not all of its physical extent has been properly sur veyed. e system is delimited from the east by the Cueva Mis chel sink depression and from the south by the Ojos de Cristal sink depression. While the vertical Pokmon 1 forms its northern limit, the system is cut o by the vertical wall of the Roraima Tepui in the southwest. Between the main thrust of the Cueva de los Pmones sector and the edge of the meseta, there is an area containing a large number of underground passages. us, the greatest possibility of discovering new passages most likely lies in the area between the southernmost branch of Cueva de los Pmones and the Cueva del Hotel Gucharos sectors. ere is a potential to discover approximately 1.5 km of additional passages here. Other locations with great potential to contain unexplored cave systems or passages can be found in the area northeast of Pokmon 3 towards Cueva con Bloques de Piedra (mda et al., 2003). Currently, we postulate that this cave system continues to other inow branches from inside the mountain, and this creates potential to uncover about a further 1.5 km of passages. e most challenging area for future explorations lies in the massif north of Cueva de los Pmones. e relief at the surface between the mesa El Maverick, which at 2,810 m a.s.l. is the highest point of the Roraima Tepui, and a mound north of the Cueva Asxiadora, Cueva de Gilberto and Fragmento Marginal sector has disintegrated due to numerous vertical crevices. is rugged relief also contains several extensive at-based depres sions draining to the underground (Fig. 35). From this site, it is possible to enter a cave not necessarily connected to the Ojos de Cristal Cave System, although it may belong to the same compact system from a genetic point of view. ere is added potential here to discover a further kilometres of cave passages. One of the most important questions which still requires explanation Fig. 34: A smaller tributary branch in the Cueva Mischel sector. –


is whether all the water is drained exclusively by the windows in the outer walls of the tepui, or if they are also conducted to deeper parts of the rock massif and then rise in resurgence at the impediment of the mountain, similar to the Tun Deut or Doble Tubo del gua on the southern Roraima slopes (mda et al., 2003). We presume that some water inltrates deeper parts of the mountain through narrow cracks which are inaccessible to humans due to their small size. 2.5. HYDROGEOCHEMISTRY Few scientic papers deal with the exogenous geochemistry of the tepuis. e soil and natual water geochemistry on Chimant Massif was investigated by Briceo & Paolini (1992) and Barreto (1992); Aubrecht et al. (2008 a , 2011) researched geochemistry of the natural waters of Chimant Massif and Roraima Mountain. In addition, geochemistry of the natural waters on the remain ing table-mountains was published by Chalcra & Pye (1984), and the chemistry of the Auyn Tepui waters was described by Mecchia & Piccini (1999) and Piccini & Mecchia (2009). 2.5.1. Sampling of natural waters and related eldwork e hydrogeochemical eldwork consisted of taking water samples, examining their eld parameters and performing colorimetric analyses, as summarized in Table 2. Water samples were collected from underground streams, dripping from walls and speleothems, and also from surface streams, springs, ponds and swamps. Sampling and eld analysis were performed during both the 2007 and 2009 expeditions. Sample amounts of 50 ml underwent colorimetric analysis performed at base camp on the collection day (Fig. 36C), and 15 ml of each sample was sealed in a plastic container and taken to a laboratory for 18 O and 2 H . determination. Samples were ltered in situ using a 0.45 m mesh diameter and each sample was run in duplicate (Fig. 36A). e pH and electric conductivity (EC) were established in the eld by the WTW pH/Cond 340i SET eld device (Fig. 36B). Dur ing the 2007 expedition, acidity and alkalinity measurements were done by titration, but this method was abandoned because all values fell under detection limits. e Merck Spectroquant Multy portable colorimeter was used for colorimetry analysis of Fe, Mn, SiO 2 -Si, Al, PO 4 3 -P, NO 3 -N, NH 4 + -and N. 2.5.2. Results of geochemical investigations e pH values of all water samples were slightly to moderately acidic, between 3.3 and 5.6, with the pH values above 5 being reg istered for samples of cave drippings and ponds on Chur Tepui. e values of electric conductivity (EC) were also very low, ranging between 2 and 28 -1 (Figs. 37, 38). Considerable dif ferences were noted in this relatively narrow interval for samples . rf f – nfnr, n f Fig. 35: View from the highest peak of Roraima Tepui – El Maverick (2,880 m a. s. l.) to the surface. The Ojos de Cristal Cave System lies below this.


Tab. 2: Table summarizing eld water analysis during the sampling campaigns in 2007 and 2009. Sample name Site name Site type Expedition pH Conductiviy ( -1 ) Fe (mg.l -1 ) SiO 2 -Si ( -1 ) Al 3+ (mg.l -1 ) PO 4 3 P (mg.l -1 ) NO 3 N (mg.l -1 ) Mn (mg.l -1 ) CH-C-1 Chur, Cueva de Bautismo del Fuego underground river 2007 4.09 22 0.04 0.49 0.01 6.2 CH-C-2 Chur, Cueva Caon Verde underground river 2007 22 0.01 0.27 CH-C-3 Chur – Cueva Charles Brewer, the farest point of the cave (Gallery of Adina) underground river 2007 2.54 20 0.07 0.22 0.28 <0.5 CH-C-4 Chur – Cueva Charles Brewer, Orinoco Gallery dripping water 2007 2.52 6 0.03 3.05 0.09 0.05 CH-C-5 Chur – Cueva Charles Brewer, Lago Carnicero underground river 2007 2.47 20 0.09 0.22 0.25 <0.5 CH-C-6 Chur – Cueva Charles Brewer, Planetario de Cesar Barrio underground river 2007 2.51 20 0.11 0.21 0.19 <0.5 CH-C-7 Chur – Cueva Charles Brewer, the outlet of the underground river underground river 2007 2.52 20 0.12 0.2 0.14 <0.5 CH-S-1 Chur – surface creek 2007 3.91 19 0.22 0.54 0.13 <0.5 CH-S-2 Chur – surface swamp 2007 5.64 23 0.25 0.51 0.52 CH-S-3 Chur – surface creek 2007 3.93 18 0.15 0.77 0.15 <0.5 CH-S-4 Chur – surface spring – seepage from a swamp 2007 5.48 25 0.08 0.5 0.16 <0.5 CH-S-5 Chur – surface spring – seepage from a swamp 2007 26 0.06 0.41 0.03 1.1 CH-C-1-09 Chur – Cueva Charles Brewer, Cascadas de Moravia dripping water 2009 5.2 7 0.01 3.35 0.04 0.8 CH-C-2-09 Chur – Cueva Charles Brewer, the outlet of the underground river underground river 2009 4.58 9 0.01 0.08 34 0.04 0.4 0.06 CH-C-3-09 Chur – Cueva Juliana underground river 2009 4.38 18 0.1 0.56 39 0.02 0.3 0.18 CH-C-4-09 Chur – Cueva Juliana dripping water (barro rojo) 2009 5.26 24 1.7 3.26 106 0.1 0.9 0.06 CH-C-5-09 Chur – Cueva Juliana dripping water 2009 5.3 0.89 3.26 153 0.03 0.7 0.13 CH-C-6-09 Chur – Cueva Charles Brewer, Gran Galeria Karen y Fanny water dripping from a speleotheme 2009 28 16.03 CH-S-4-09 Chur – surface, Ro Rojo river 2009 3.3 25 0.07 0.02 92 0.02 1.3 <0.02 –


collected from the dierent sources of streams, springs and cave wall drippings, and also in the sample collection time. ere was an overall tendency for higher electrical conductivity values for the surface and cave streams and spring samples collected in the 2007 expedition than those recorded in 2009. e 2007 expedi tion registered 18 – 27 -1 in the samples from Chur and 5 – 19 -1 in the samples from Roraima, while 2 – 18 -1 were recorded for the Chur samples and 5 – 8 -1 for the Roraima samples in 2009. It is quite obvious that the stream and spring samples collected on Chur had higher electrical conduc tivity values than those on Roraima. Low and stable values were typical for samples of the water dripping from the cave walls: 7-8 -1 for samples from Cueva Charles Brewer and Cueva Juliana on the Chur Tepui. Considerably lower electrical conductivities were observed in the cave drippings of the Cueva de los Pmones sector on Roraima: 2-3 -1 . Analyses were performed on water samples dripping from the red mud in Cueva Juliana on Chur Tepui and on another dripping from alarge inorganic opal stalactite in Cueva Charles Brewer, and these had higher electrical conductivity values at 24 -1 from the red mud source and 28 -1 from the speleothem. An overview of the studied speleothems is recorded in Aubrecht et al. (2008 a, b ). With the exception of the cave drippings results, all SiO 2 -Si concentrations in Chur samples ranged between 0.08 – 0.77 . rf f – nfnr, n f CH-S-5-09 Chur – surface, northern part of the plateau creek 2009 4.58 2 0.03 0.16 <20 0.03 <0.5 0.07 CH-S-6-09 Chur – surface, northern part of the plateau creek 2009 4.54 9 0.04 0.12 <20 0.03 <0.5 <0.02 CH-S-7-09 Chur – surface, northern part of the plateau creek 2009 4.56 11 0.07 0.21 18 0.05 <0.5 <0.02 CH-S-8-09 Chur – surface, valley below the entrance of the Cueva Charles Brewer creek 2009 4.38 14 0.03 0.28 69 0.1 0.8 0.06 Ro-C-1 Roraima, Cueva de los Pemones underground river 2007 12 0.05 0.97 0.14 0.7 Ro-C-2 Roraima, Cueva de los Pemones dripping water 2007 2 0.03 2.3 0.09 1.2 Ro-C-3 Roraima, Cueva de los Pemones underground river 2007 14 0.03 1.01 0.13 1.9 Ro-C-4 Roraima, Cueva de los Pemones underground river 2007 18 0.05 1.36 0.16 5.6 Ro-C-5 Roraima, Cueva Ojos de Cristal underground river 2007 10 0.02 0.79 0.08 <0.5 Ro-C-6 Roraima, Cueva Ojos de Cristal underground river 2007 13 0.02 0.74 0.1 1.2 Ro-C-7 Roraima, Cueva Ojos de Cristal, 20 m far from the portal underground river 2007 13 0.04 0.73 0.15 1.6 Ro-S-1 Roraima, Tun Deut spring 2007 19 0.01 1.01 <0.01 <0.5 Ro-S-2 Roraima, lake beneath the Valle de los Cristales lake 2007 5 0.03 0.09 0.04 <0.5 Ro-C-1-09 Roraima, Cueva de los Pemones underground river 2009 4.9 8 0.07 0.19 265 0.03 <0.5 0.08 Ro-C-3-09 Roraima, Cueva de los Pemones dripping water 2009 5.65 3 0.03 2.27 <20 <0.01 <0.5 <0.05 Ro-C-5-09 Roraima, Cueva Ojos de Cristal, 100 m from the entrance underground river 2009 4.71 8 0.04 0.14 21 <0.01 <0.5 <0.05 Ro-S-2-09 Roraima, Tuna Damu creek 2009 5.05 8 0.04 0.47 <20 <0.01 <0.5 <0.05 Ro-S-4-09 Roraima, Tun Deut spring 2009 4.76 5 0.06 0.16 <20 <0.01 0.3 0.04


mg.l -1 with slightly higher concentrations in samples collected during the rst expedition (Fig. 38). While the SiO 2 -Si concen trations in samples collected from similar sources on Roraima during the rst expedition ranged from 0.73 to 1.36 mg.l -1 , one sample from a pond representing the Ro Arabop spring source contained extremely low concentration of 0.09 mg.l -1 . is water sample also registered the lowest electrical conductivity meas ured in streams at 5 -1 . While SiO 2 -Si concentrations in the samples collected in the 2009 expedition had a narrower interval of 0.14 – 0.47 mg.l -1 , there was a considerably higher range of 3.05 to 3.36 mg.l -1 recorded in samples dripping from the Cueva Charles Brewer walls. A similar concentration of 3.26 mg.l -1 was registered in the water sampled from red mud in Cueva Juliana, while samples dripping in the Cueva de los Pmones sector on Roraima were slightly lower at 2.3 and 2.26 mg.l -1 . However, the highest SiO 2 -Si concentration of 16.03 mg.l -1 was recorded in the water dripping from the opal stalactite in Cueva Charles Brewer. Fe concentrations in all samples ranged between the detec tion limit of 0.01 mg.l -1 and a maximum concentration of 1.7 mg.l -1 (Fig. 39). Samples collected on the 2007 expedition from surface and underground streams, ponds and Chur Tepui cave drippings had slightly higher maximum concentrations of 0.22 mg.l -1 compared to the 0.07 mg.l -1 in 2009. Lile dierence in the ranges of Fe concentrations was noted in the samples collected on Roraima. ese values were 0.01 – 0.05 mg.l -1 in 2007 and 0.03 – 0.07 mg.l -1 in 2009. Extreme Fe concentrations recorded in the cave drippings from the “Barro Rojo ” (red mud) in Cueva Juliana were 0.86 – 1.7 mg.l -1 in 2009. e Fe concentration in the small creek owing near the red mud in Cueva Juliana was 1 mg.l -1 . A comparison shows cave drippings collected from the “pure” quartzite cave walls containing Fe in the range of 0.01 to 0.03 mg.l -1 . Al concentrations were measured only in samples from the 2009 expedition (Fig. 40). Concentrations in all samples from Roraima and small creeks in the northern Chimant swamps were below the detection limit of 20 mg.l -1 . Moderately higher concentrations were recorded in Cueva Charles Brewer sector underground streams and Cueva Juliana, at 34 and 39 mg.l -1 , respectively. Al concentrations in the stream of the deep tectonic valley (probably draining cave systems of the Chur Tepui) in the western part of the Chur Tepui were up to 69 mg.l -1 and 92 mg.l -1 in the water of Ro Rojo, the river of unknown origin which most likely drains the valley. e highest Al concentra tions were measured in red mud dripping samples collected in Cueva Juliana at 106 and 153 mg.l -1 respectively. e Mn concentrations in the surface stream samples ranged between the detection limit of 0.02 mg.l -1 and 0.06 mg.l -1 , while those from the underground caves and drippings were moder ately higher at between 0.06 and 0.18 mg.l -1 . 2.5.3. Processes inuencing water chemical composition Natural waters on the table-mountains’ mesetas are inuenced by the following main factors: – precipitation water composition – processes in soils and peats – rock-water interactions Although rainwater composition was not investigated during our expedition, Briceo & Paolini (1992) reported the composition of several samples collected on dierent mesetas of the Chimant Massif. According to their ndings, these precipitation waters were quite acidic, at average pH of 4.59 and range of 4.0 to 5.09. ey also contained very low dissolved maer content with an average conductivity value of 7.4 -1 with a range of 4.6 to 9.7 -1 . Other measured contents included; the Ca and Mg concentrations were below the detection limits, while the aver age Na and K contents were both 0.06 mg.l -1 and the average Cl content was 0.35 mg.l -1 . Mecchia & Piccini (1999) recorded a wider interval in pH and electrical conductivity values in the rainwater samples collected on Auyn Tepui, the pH value range was 3.8 to 6.5, and the electrical conductivity values ranged from 1.3 to 15.9 -1 . Variations in pH and electrical conductivity values generally depend on the acidic gases CO 2 , SO 2 and NO x , and also on dust content in the atmosphere. e Gran Sabana area is considered remote with a minimum of industrial factors inuencing rainwater composition. In addition, because of low variability in the geology of the general Gran Sabana area, dust composition is most likely not responsible for these pH and electrical conductivity variations. erefore, the variations may have been inuenced by rainwater sampling methods. Although rainwater is one of the few primary sources of nutri ents such as Ca, Mg, K, their content there is oen below the de tection limit. e concentrations of these nutrients are increased due to evaporation and pre-concentration in plant bodies due to multiple recycling of organic debris. e greatest inuence on – Fig. 36: Hydrogeochemical eld work. A – Water sampling and ltering through a 0.45 m mesh in Cueva Charles Brewer, Chur Tepui. B – Measurement of the pH and electrical conductivity in water samples, Cueva Ojos de Cristal, Roraima. C – Colorimetric analyses in the Northern Camp, Chur Tepui.


the table-mountains’ natural waters is the dilution eect dur ing the rainy season as this provides more eective dissolution processes . e rainwater collected in small pools (opferkessels, kamenitzas) has an eect on sandstone weathering, because it is mediated by cyanobacteria (Fig. 43A). Naturally, since water completely evaporates from these pools, it cannot contribute to the groundwater and surface water systems in tepuis. e eect of rainwater is demonstrated on the EC/pH rela tionship (Fig. 37). is graph depicts the negative dependency of electric conductivity (EC) on pH. is dependence for the Chimant Massif’s natural waters was also described by Briceo & Paolini, (1992). e graph clearly indicates that waters diluted by rainwater typically have higher pH and lower EC values, while more evaporated waters possess higher EC and lower pH values. e highest pH values and lowest EC values were registered in samples taken from water dripping down the quartzite cave walls. eir pH show a generalized equilibrium with atmospheric CO 2 , while their low EC values highlight the lack of minerals dissociat ing to ions in their dissolution processes (see the next chapter). e slightly higher pH and lower EC values in the water samples from Roraima in the 2009 expedition were caused by the high rainfall which occurred on Gran Sabana in that January and February. Samples collected on Chur Tepuy at the same time had wider EC and pH value intervals, as depicted in Figure 37; samples from Fig. 37: The pH – EC relationship in natural water samples. Fig. 38: Relationship of electrical conductivity and Si contents of natural waters. . rf f – nfnr, n f


small creeks close to the northern edge of the meseta following heavy rainfall are shown on the le, while a sample from the Ro Rojo in the lowest part of the deep valley below the Cueva Juliana entrance appears on the right. Samples from Chur Tepui in 2007 are grouped below those of 2009, because they are more inuenced by evaporation increasing organic acid and dissolved salts concen trations. Similar trends are apparent in the Si-SiO 2 contents and EC relationship in samples collected from the streams (Fig. 38). Peatbog geochemistry on the Chimant Massif was described by Briceo & Paolini (1992), and its pedology was discussed by Barreto (1992). Peat normally occurs in lower situated zones covered by dense savanna vegetation (Briceo & Paolini, 1992). e organic debris is in dierent stages of decomposition and water content is usu ally over 85%. Its maximum thickness on Chimant is 2.1 m, as recorded on Akopn Tepui. e upper (brous) layer consists of living and dead plant roots and plant detritus, while the lower (hemic) layer is composed of decayed products from organic debris. e Ca, Mg, Na, K and Si concentrations in the plant and peat material decrease with the depth of the peat layer due to their utilization by plants (Briceo & Paolini, 1992). ese nutrients are leached from the substrate in very low amounts, and while they are primarily utilized from the rainwater and substrate leachate they are secondarily recycled from decayed organic debris. Although the above chemical concentrations all decreased, the Fe content increases with depth due to its higher redox potential values (Briceo & Paolini, 1992). Barreto (1992) identied three soil types on the mesetas of the Chimant Massif: entisoils, histosoil and ultisoils. Histosoils occur in loy places and have 0.60 m thickness while ultisoils in the deeper valley can be up to 2 m thick. ese laer consist of two layers, the upper 0.30 – 0.40 m thick layer is composed of less decomposed organic materials, while the remainder consists of totally decomposed organic debris. ese soils are quite acidic, with pH below 5, and their potassium, calcium and magnesium contents are extremely low, thus causing the very low fertility found in these soils. Despite these deciencies, organic nitrogen, phosphorus and carbon contents are very high. – Fig. 39: Relationships of concentrations of Fe with Si (A) and electric conductivity (B).


Since the soils and peatbogs represent environments with the highest water retention capacity, they serve as a relatively stable water source for numerous springs and watercourses draining the surrounds (Fig. 41A). e inuence of the soils and peatbogs on the chemical composition of the surface and groundwaters of Chimant Massif, and other table-mountains is mainly manifested by high amounts of organic acids and humic substances. ese cause the yellow-brown-red colour ing of waters (Fig. 41C), and the thick yellow foam which is quite apparent below waterfalls (Fig. 42). Higher amounts of organic acids contribute to the overall acidic character of these waters. Other eects of intensive organic maer decay are CO 2 production and dissolving carbonic acid which contribute fur ther to lowering of pH values (Fig. 41B). ese processes are highlighted in Figure 37. e negative dependency between pH values and electrical conductivity is also due to higher organic acid content in the evaporated waters. A typical example is the Ro Rojo in the lowest part of the deep valley beneath Cueva Juliana entrance (Fig. 41C). is river most likely drains a larger area on the western part of the Chur Tepui, because the high content of organic acids cause a reddish river water colour and a low pH of 3.3. e rock-water interactions in the table-mountains involve the dissolution of quartz and alumino-silicate minerals. A nu merical dissolution model for quartz, anorthite and amorphous silica by USGS PHREEQC geochemical modelling soware was prepared to demonstrate the eects of mineral dissolution (Parkhurst & Appelo, 1999). e results of the model concur with the experimental data of Correns (1949) (cf. Fig. 44). e dissolution of quartz in water under natural conditions is a sim ple hydration process resulting in the formation of silicic acid: SiO 2 +H 2 O H 4 SiO 4 ( aq ) (1) e silicic acid then dissociates ionically to give: H 4 SiO 4 (aq) H 3 SiO – 4 + H + (2) Fig. 40: Relationships of concentrations of Al with Si (A) and electric conductivity (B). . rf f – nfnr, n f


Reaction (2) signicantly increases the solubility of the quartz, but only in a pH above 9. Below this value, the solubility is slightly aected by pH and water ionic content (Fig. 44). Complexing silicic acid with certain organic acids increases quartz solubility (Benne, 1991). In dynamic systems with high energy, such as karstic aquifers, the mineral dissolution is oen controlled by reaction kinetics, as also occurs in relatively soluble minerals, including calcite. e dissolution of quartz at room temperature is extremely slow, and is controlled by the breaking of bonds and hydration of the silica on the mineral surface (Dove & Rimstidt, 1994). e dis solution rate can be increased from 10 -17 moles cm 2 .s -1 at 25 C in pure water (Benne, 1991) to 10 -14 moles cm 2 .s -1 at high pH values and in a concentrated NaCl solution (Dove & Rimstidt, 1994), and also by the presence of organic compounds such as citrate to 10 -15.5 moles cm 2 .s -1 (Benne, 1991). e foregoing makes it clear that quartz dissolution is a longterm process and long-lasting exposure to a tropical humid cli mate is necessary to remove larger amounts of SiO 2 (Doerr & Wray, 2004). Although lile data is available on water chemical composition in Venezuelan table-mountains, very low silica concentrations have been reported in the water drained from quartzite in the Roraima Supergroup. Chalcra & Pye (1984) reported that silica contents are below 1 mg.l -1 in streams sampled on the table-mountains tops. Similar results were registered by Piccini & Mecchia (2009) for Auyn Tepui. e silica contents of streamwater sampled by our team both on the surface and in the caves concur with literature data, and in only two cases did they slightly exceed 1 mg.l -1 . e silica contents and electric conductivity values in these samples appear to be considerably aected by hydrological conditions, as they were slightly higher in samples collected at the beginning of 2007 when the rainfall was lower than in our second expedition two years later. e dierent values occurred even though both of the expeditions were conducted during the dry period of January and February (Fig. 38). e pH of water at the top of the tepuis is quite low. According to Briceo & Paolini (1992) this ranges between 3.4 and 6.0 for natural waters at Chimant Massif, while Mecchia & Piccini (1999) and Piccini & Mecchia (2009) reported pH values from 3.5 to 4.9 for waters sampled on the Auyn Tepui. Our samples had pH values ranging from 3.3 to 5.5, and the combination – Fig. 41: A – One of the springs from a small creek draining a swamp area on the northern part of Chur Tepui. B – Gas bubbles emanating from organic debris decomposition in a small pool in the swamp, Chur Tepui. C – The typi cal yellow-reddish color of waters on the tepuis is caused by organic acids from organic debris decomposition processes in Ro Rojo, Chur Tepui. Fig. 42: A – Dense and sti foam remnants on rocks in a creek on Chur Tepui. B – Foam accumulated on an unnamed river owing from the Cueva Charles Brewer sector. C – Foam remnants following a decrease in water level in Cueva Charles Brewer.


of all these values indicates that pH values in natural surface waters uninuenced here by human activity are extremely low. is phenomenon is common for natural waters of the quartzite terrains of the Gran Sabana (Briceo et al., 1991). It is caused by; lack of alumosilicates and carbonates which act as acidity buers; the presence of organic acids from organic debris de composition in surface swamps; and the CO 2 production in organic maer decomposition. An interesting negative relation ship was identied between the pH and EC values in the water samples, and this relationship was also reported by Briceo & Paolini (1992). In addition to the eects of rainwater on the soil and peatbog described above, rock-water interactions also aect this relationship, where high precipitation diminishes the neutralization eect of the alumosilicate dissolution. Con sequently, natural waters in these areas are generally strongly undersaturated compared to alumosilicates, even in extremely low pH conditions where their solubility is lowest (compare Figs. 37, 38 and 44). Very high organic acid concentrations did not signicantly increase quartz solubility because silica complexing by organics is eective only at high pH (Ingri, 1977). e high est Si content of 16.03 mg.l -1 was recorded in the water sample dripping from the opal stalactite in the Cueva Charles Brewer sector. is extreme concentration was above the equilibirum concentration with quartz, and it was also associated with the highest conductivity value of -1 , which indicates that this is due to water evaporation on the cave walls rather than a consequence of dissolution. e most eective quartz dissolu tion process was observed on the cave walls, where air moisture precipitates and causes corrosive dissolution due to strong un dersaturation, compared to that of SiO 2 in the precipitated water. is process was recognized in samples of water dripping from the cave walls (Fig. 43B-C). e origin of the dripping water from condensed air moisture is apparent from the higher silica content of 2.3 – 3.3 mg.l -1 and very low electrical conductivity values of 2 to 7 -1 presented in Fig. 38. Further evidence is provided by the 5.3 to 5.6 pH values of the dripping water, which are close to the 5.6–5.7 pH value of distilled water in equilib rium with atmospheric CO 2 . ese values illustrate a process of almost pure SiO 2 dissolution in distilled water, as proven by the accompanying extremely low electrical values described above. ese occur because silicic acid, which is a dissolution product of SiO 2 , does not dissociate below a pH of 9, and therefore it Fig. 43: A – Small pools in the sandstone surface lled with water following heavy rain. Intensive microbially intermedi ated weathering is evident in these pools on Chur Tepui. B – Condensed water dripping from a cave wall in Cueva Charles Brewer, Chur Tepui. C – Water dripping from “Barro Rojo” accumulated in Cueva Juliana, Chur Tepui. D – Depiction of a probably bio-corroded quartz pebble on Roraima. . rf f – nfnr, n f


does not contribute to the electric conductivity. Despite this, although the dissolution process is extraordinarily eective, it has only a local importance because it occurs only in specic circumstances. e circumstances required here are that the moisture can precipitate in a well developed underground area with minimum air ow, so that water vapour is not blown away. Since the amount of dissolved and mobilized silica is volumetri cally negligible, its importance as a key process in speleogenesis is also negligible. Some arenites, such as arkoses and subarkoses, also contain alumosilicate minerals, mainly micas and feldspars. ese alu mosilicates dissolve in acidic water more eectively than quartz (Fig. 44; see also diagrams in Valeton, 1972; experiments of Franklin et al., 1994). e dissolution, or weathering process, of aluminosilicate minerals is an incongruent process where insoluble remnants are formed during the dissolution process. ese remnants are secondary minerals including clays such as montmorillonite, illite and kaolinite and various Fe and Al oxides and hydroxides. Here, released silica may further precipitate as opal-A. e types of secondary minerals depend on the water pH, temperature and ion content and also the composition of the primary alumosilicate. A typical example of an alumusilicate dissolution reaction is the following albite dissolution with the secondary kaolinite mineral: 2Na( AlSi 3 ) O 8 + 2H + + 9H 2 O Al 2 Si 2 O 5 ( OH ) 4 + 2 Na + + 4 H 4 SiO 4 (3) e presence of alumosilicates in the tepui rocks is apparent in thin sections and in the samples from less lithied quartzite layers examined by SEM (cf. Fig. 61). Under humid and warm tropical conditions, the incongruent dissolution processes together with other silicate rock weathering processes result in laterite forma tion. In many cases, there are white, heavily kaolinized arkosic arenites with red lateritic caps, as are visible in Gran Sabana. e red mud found in excessive quantities in both examined cave sys tems registered a mineral composition of goethite, kaolinite, illite, quartz and pyrophyllite, thus representing true laterite (Tab. 4). It is reasonable to presume that the mud accumulations observed in the caves are only remnants le by the subterranean streams and that the original amount of red mud was much higher. e dissolution processes in the laterite bodies have considerable inuence upon water chemistry but this was manifested only in water dripping from the laterite bodies. Si content was recorded up to 3.26 mg.l-1 in such samples in Cueva Juliana on Chur Tepui, and although this content is quite similar to that in other dripwater samples, the electric conductivity here was 24 Scm-1 (Figs. 35, 36). is was most likely due to the higher concentra tions of ions originating in alumosilicate dissolution reactions, Fig. 45: Field measurements of rock hardness by Schmidt hammer in Cueva Juliana. – Fig. 44: Solubility of quartz, amorphous SiO 2 and anorthite from the thermodynamic model constructed in PHREEQC.


and also presumably from kaolinite and/or other secondary phylosilicate dissolution under conditions of low pH: 1 2 Al 2 Si 2 O 5 ( OH ) 4 + 5 2 H 2 O Al ( OH ) 3 + H 4 SiO 4 (4) Relatively high concentrations of Al 3+ in water samples drip ping from the red mud registered 106 and 153 mg.l -1 , and this is 38 times higher than in the surrounding stream water. ese were a consequence of gibbsite and/or other aluminium oxides/ hydroxides dissolution under acidic conditions: Al ( OH ) 3 + 3H + Al 3 + + 3H 2 O (5) Higher Fe 2+ concentrations in these dripping water samples are a sign of goethite dissolution. Fe ( OH ) 3 + 3H + Fe 3 + + 3H 2 O (6) Stream waters at the table-mountain pediment are aected by dissolution processes in arkosic arenites. For example, there are silica concentrations up to 3.4 mg.l -1 in Ro Carrao (Piccini & Mecchia, 2009), which may indicate that the lateritization in the existing cave passages occurred in its nal stages. 2.6. SPELEOGENESIS OF THE CHARLES BRE WER AND OJOS DE CRISTAL CAVE SYSTEMS 2.6.1. Introduction Several aspects must be considered and several methods used in order to explain the speleogenesis of Charles Brewer and Ojos de Cristal cave systems – the two largest sandstone cave systems in the world. However, results of this speleogenetic research go beyond the initial target and help us to beer understand the geomorphological evolution of tepuis. It is rst necessary to emphasize the extreme diculties encountered in establishing the genesis of sandstone and quartzite caves, because the origin of the arenitic caves in Venezuelan tepuis has created scientic disputes all over the world. Caves and karstic phenomena are common in limestone terrains and in other areas containing rocks with similar or greater solubility, including gypsum and salt. In this regard, there is also the quandary on caves formed in other rocks, such as silicates. All karst-like phenomena that evolved in non-carbonate environments were initially aributed to the pseudokarst category, but the term “karst” was later ex tended to some non-carbonate rocks (see Doerr & Wray, 2004 for overview). Most recent denitions state that dissolution is the determining factor of karstic phenomena (Jennings, 1983; Wray, . rf f – nfnr, n f Fig. 46: Rockfalls represent the main cave-forming process in later stages of speleogenesis. A – Cueva Colibri, B – Cueva del Hotel Gucharos in the Ojos de Cristal Cave System, C – Collapsed entrance of Cueva Tetris, D – Cueva Caon Verde.


Fig. 47: Horizons of poorly-lithied arenites on the tepui surfaces. A – Two superimposed horizons with poorly-lithied arenites, forming the depressed re lief between well-lithied quartzites on Chur Tepui close to base camp, served as sampling sites for petrographic studies in 2007. B – Superimposed poorlylithied horizons on Roraima. Typical features are “nger-ow” pillars. C – Another poorly lithied horizon on Roraima. “Finger-ow” pillars are combined by “honeycomb”-like vein network (h). D-F – Typical features of poorly-lithied horizons on Chur: o – overlying quartzite bed, h– “honeycomb”-like vein network, u – underlying quartzite bed, p – “nger-ow” pillar, s – poorly lithied sand. (D) base camp in 2007; (E-F) locality gured in 47 A . –


1997 b ; Doerr & Wray, 2004; Martini, 2004). Silicate rocks gener ally have very low solubility, and therefore caves which formed in silicate rocks were considered to be pseudokarst, as most workers believed that dissolution does not play an important role in their formation. However, many works later emerged which applied the term karst to silicate caves which occurred either in granites (Willems et al., 2002; Twidale & Vidal Roman, 2005; Vidal Roman & Vaqueiro Rodrigues, 2007; Cioccale et al., 2008), or else in sandstones (see reviews in Wray, 1997 a-b , 1999). Accord ing to these authors, dissolution is denitely the main process forming these caves, regardless of how slowly this progresses. e term “arenization” was then coined to describe silicate rock weathering. Martini (1979) used this term for sandstone rocks, extending its meaning to dissolution of the cements in arenitic rocks. Accordingly, this turns quartzites to the so-called “neosandstone” (see Martini, 2004). is loose sand material, when eroded and winnowed, provides subterranean spaces. If this arenization theory was accepted, most sandstone caves might be aributed to karst because this dissolution is considered to be a triggering stimulus for cave formation. e main evi dence that dissolution occurs in silicate caves is provided by the silica speleothems which occur in most silicate caves. ese are mostly composed of opal-A, which slowly turns into opal-CT (crystobalite-tridymite) and then into microcrystalline quartz (cf. Aubrecht et al., 2008 a and discussion on speleothems in this volume). e question is whether the silica dissolution is so important that the Venezuelan arenitic caves can be correctly ranked among karstic ones. Our team presents a dierent view on the genesis of sandstone caves where we challenge their karstic origin on the basis of preliminary results from our two speleologi cal expeditions to the Venezuelan Gran Sabana (Aubrecht et al., 2008 b ). Although it was accepted that dissolution may be quite important, this dissolution involved feldspars, micas and clay minerals in a process of lateritization, rather than quartz dissolu tion (Aubrecht et al., 2011). In this volume we provide further data and illustrations to support this view, and consequences of this premise on the geomorphological evolution of tepuis. 2.6.2. Material and methods Our geological, geomorphological and speleological observa tions were focused on phenomena relevant to the solution of the speleogenetic problems. is mainly centred on the dierential weathering of the various kinds of arenites on the tepuis surfaces and caves in the Matau Formation, and also on morphological aspects of the various stages of speleogenesis and its nal mani festations on the surface. Sites with dierent arenite lithication and erosion provided 40 samples for petrographic analysis in thin-sections and under SEM. Dierences in rock hardness were observed empirically, and 23 sites were measured by Schmidt hammer (Fig. 45). e Schmidt hammer enables a simple and quick eld test of the rebound hardness of rock, delineation of the horizons of various weathering/alteration stages along a given prole, and also assessment of the characteristics of the rocks’ strength. e rebound is measured by touching the rock rmly with the Schmidt hammer and releasing the strained spring with a cylinder inside the hammer. e cylinder rebounds depending on the rock hardness and this is recorded mechanically on apa per scroll which the mechanized version of the hammer shis aer each straining. e measurements (159 measured points) were focused on so, poorly lithied layers, hard overlying and underlying layers and also on the “nger-ow” pillars penetrat ing the so layers, which are discussed in later chapters. Most of the measured rocks were wet, but not completely saturated with water. Hardness at each point was measured 10 to 15 times and the average values were estimated, following exclusion of the extreme values. Since there was insuent number of arenite samples, the measured rocks uniaxial compressive strength was calculated from the rebound values. Mineralogical composition of the samples was determined optically and also by X-ray diraction analysis (XRD). e mineral composition of selected samples of sandstones and the clay fraction of red mud were established by X-ray powder dif fraction analysis using a Philips PW 1820 diractometer ed with agraphite monochromator and Cu tube. Scanning steps of 0.02 2 withcounting time of 1 sper step from 4 – 74 2 were used for sandstone samples. Oriented and non-oriented specimens were prepared for analysis. e XRD data for oriented specimens were obtained in air-dry and ethylene-glycol-solvated (EG) states. Selected samples were also studied by infrared spectroscopy, Raman spectroscopy and electron microprobe analysis. Polished thin-sections of each speleothem were prepared for microscopic investigations under polarized light. 2.6.3. Results and interpretations Field geomorphological and geological obser vations and their importance in speleogenesis Erosion and rockfalls, which recently prevail in the Charles Brewer and Ojos de Cristal cave systems have concealed their true speleogenetic processes (Fig. 46). e sandstone beds have angular edges and the caves are full of fallen angular blocks. e signs of dissolution in the sandstone beds smooth edges and bizarre etching paerns are too rare to explain recent stages of the caves’ evolution. All the trigger and structural factors acting during initial stages of the caves’ evolution are now obliterated in the mature parts of the cavern systems. While our observations of surface geomorphology of these tepuis and their subterranean spaces have supplied some clues to their speleogenetic processes, many of these clues emanated also from caves which are still in their initial stages of evolution. e sandstone surfaces of tepuis are very uneven and bizarre, obviously due to an inhomogeneous lithication of the Protero zoic arenites. is is especially apparent in areas where arenite beds form overhangs (Fig. 47). e overlying and underlying beds are hard, well-lithied rocks formed by sandstones to quartzites, so that sampling was possible only with strong ham mering. However, the beds inbetween are only slightly lithied or completely unlithied so sands and sandstones, so that it was almost impossible to take lithied samples for petrographic microscopic study, even aer digging 30 cm deep by hand. ese poorly lithied beds are penetrated by perpendicular pillarshaped bodies. ese are narrower in the middle, but they have . rf f – nfnr, n f


funnel-like widening at either end, with the lower funnel less developed than the upper one (Fig. 47C-E). ey are relatively well-lithied rocks, ranging from sandstones to quartzites, and the combination of overhangs and pillars provides aractive decoration for most tepui surfaces (Fig. 48). e origin of these pillars is purely diagenetic and their pres ence proves that the soness of the poorly lithied beds is pri mary rather than being secondary. e pillars are considered to originate by a “nger ow” mechanism (cf. Aubrecht et al., 2008 b , 2011). e main factors inuencing diagenetic variability were the diering hydraulic properties of the sediment in dierent layers which inuenced its hydraulic conductivity. e diagenetic uids most likely penetrated vertically from the overlying strata as a descending diagenetic uid ow. In ner-grained sediments, these diagenetic uids lled the intergranular spaces evenly and resulted in the formation of diagenetically well-lithied beds, resistant to weathering. In coarse-grained arenites with higher hydraulic conductivity below the ne-grained beds, the evenly distributed descending diaganetic front divided into “ngers”, where the uid ow accelerated and formed separate, nger-like ows. is process has been described in detail by various authors working with transport processes in unsaturated zones of sandy aquifers and also in soils (Bauters et al., 2000; Liu et al. 1994). A similar process is seen in snow penetrated by descending water as it leaks from melted snow above (Marsh, 1988: g. 2). Liu et al. (1994) considered that when these nger ows are generated in originally dry sandstones they are conserved as the most preferred method of inltrating solutions. is is the way pillars originated in the unlithied sands. e upper diminishing funnel shape of the upper part of the pillar originated from ow acceleration, which continued until it decelerated when approaching the less perme able boom. is retardation process is manifested in the reversely oriented funnel shape of the pillar boom (Aubrecht et al., 2008 b ). e poorly lithied beds form distinct horizons in tepui geo morphology, and these can be traced and correlated for long dis tances (Fig. 49A-C). e overlying and underlying beds protect the unlithied sand from rainfall, but they are easily eroded when accessed by horizontally owing water streams. When the over lying protective beds become weathered, broken or dissected by cles, water can then penetrate as deep as the unlithied beds, thus forming ahorizontal cave (Fig. 49E-F). Observations in the Charles Brewer and Ojos de Cristal cave systems show that pillars are present in most of the caves and in their galleries, which are still in younger stages of their evolution (Fig. 49D-H). ese usually possess low ceilings and strictly maintain one distinct layer. Relic nger-ow pillars were also observed in the marginal, uncollapsed parts of the larger galleries (Fig. 50). In some caves, incomplete “nger-ow” pillars occurred where only the upper funnel was developed. Speleologists named these forms “tetas” (teats – Fig. 51) When several superimposed winnowed horizons evolve to gether, a second collapse stage follows, leading to formation of much larger subterranean spaces (Fig. 52A). Galleries in the Charles Brewer Cave System are typically 40 metres wide, but they can also be much larger. e largest chamber found in the cave is Gran Galera Karen y Fanny. is is 40 metres high, more than 355 metres long and 70 metres wide, giving a volume of approximately 400,000 cubic metres (Fig. 52B). e initial cave-forming stages of this cave system were clearly related to the laminated clay-bearing sandstones which now persist in the lower parts of the cave (Fig. 52C). In addition to being primarily poorly lithied, their clay mineral content makes them prone to lateritization (see below). ese initial stages were followed by collapses of strongly lithied quartzites overlying the laminated sandstones (Fig. 52D). e nal stages of cave evolution oen lead to huge collapses, and these are apparent on the tepui surfaces (Fig. 53). One of the largest collapse zones is present on Chur Tepui in the Chimant Massif (Aubrecht et al., 2008 b : pl. III, g. 3). is collapse zone is sunken and the sandstone mass is dissected into large blocks which slope in dierent directions (Fig. 53F). ese blocks were evidently “undercut” by erosion of the poorly lithied sand lay ers so that they then collapsed. No other processes, including dissolution or arenization involving breakdown of cement and release of sand grains, or even weathering would be capable of creating such a huge collapse zone. e linear course of this zone highlights that it is related to tectonic fault activity (cf. Briceo & Schubert, 1992 a ), but this most likely served only as a trigger for the collapse, by enabling drainage of owing water and erosion of the unlithied strata. Collapses of the cave spaces, from which the poorly lithied arenites were winnowed, obviously led to the creation of the large abysses in the Sarisariama Plateau (Sima Mayor and Sima Menor – Fig. 9), or the well known depression El Foso on Roraima Plateau (Fig. 54A). On the basis of these observations, winnowing of the unlithied or weakly lithied sands fulls the trigger role in the formation of the sandstone caves in tepuis, and it also inuences their further evolution. Although the signs of quartz dissolution forming smooth edges of sandstone beds or bizarre etching paerns are relatively rare (Fig. 55A-C), some of these signs can be found in the caves and on the tepui surfaces. Here, the uneven, bizarre paerns may be due to etching from the increased alkalinity produced by microbial colonies (cf. Bdel et al., 2004; Brehm et al., 2005; Barton et al., 2009). Some even form photokarren, which can be seen oriented parallel to the sunlight near the entrance of Cueva Charles Brewer (Lundberg et al., 2010 b ). is same process may also be responsible for the pied surface of the tepuis. ere are numerous small pools on the surface which host various species of cyanobacteria (Fig. 55D-F). Such depressions were formerly also considered to be initial karst forms (White et al., 1966). From other aspects which contribute to cave-forming pro cesses, the presence of considerable quantities of lateritic red mud (Spanish: “Barro Rojo”) were observed. It is a ubiquitous phenomenon here, and large quantities can be found in all the ex plored Chur and Roraima caves (Aubrecht et al., 2011). is mud usually leaks from fractures and bedding planes (Fig. 56) and when desiccated it forms mounds or even speleothems, including owstones, globules and small stalactites (Fig. 57). Its colour can also sometimes be black (Fig. 56E, 57F), so that broken speleo thems oen show alternating red and black laminae (Fig. 57G). Hardness measurements Measurements were performed to objectively verify the obvi ous hardness dierences existing within the Matau Forma tion’s arenites. ese were veried empirically (Aubrecht et –


al., 2008 b ) and also by objective measurements enabled by the Schmidt hammer (Aubrecht et al., 2011). e measurements showed dierent values between the hardness of loose sands in the poorly lithied beds, and that of the well lithied overlying and underlying beds and “nger ow” pillars. e hardness dif ferences are also clearly highlighted in the average and median values of the entire set of measurements. In the scale of 0 to 100, the rebound hardness of the poorly lithied arenites ranged from 18 to 37.67 in 49 measurements; with an arithmetic average of 23.49, a median of 22.27, and a standard deviation of 4.74. e derived uniaxial compressive strength ranged from 25 MPa to 150 MPa, with the majority of values falling below 47 MPa. Although the rebound strength of the overlying and underlying beds varied, at most measured sites, it exceeded the values of the corresponding poorly cemented interlayer at each site (Fig. 58). Hardness values ranged from 18 to 63.11 in 57 measurements, with an average of 34.49, median of 31.67, and a standard devia tion of 12.19. e derived uniaxial compressive strength ranged from 26 MPa to 270 MPa, with the majority of values less than 90 MPa. e measured hardness of “nger ow” pillars ranged . rf f – nfnr, n f Fig. 48: Horizons of “nger-ow” pillars are typical decoration of Roraima surface geomorphological forms.




. rf f – nfnr, n f Fig. 50: “Finger-ow” pillars preserved in uncollapsed parts of the sides of large corridors. A,F – Cueva de los Pmones sector, B,C,E – Cueva Colibr sector, D – Cueva Charles Brewer sector. Fig. 49: A-C – Poorly lithied beds are clearly visible on the tepui surfaces and they can be correlated for long distances (A – multiple collapsed and poorlylithied horizons between Cueva Charles Brewer and Cueva Caon Verde, close to the 2007 base camp, B – collapsed poorly lithied horizon in the Guyana part of Roraima Tepui, C – multiple poorly-lithied horizons above Cueva Colibri). D-H – well preserved “nger-ow” pillars in the uncollapsed main cor ridors of cave parts during early stages of their speleogenesis (D – Cueva Colibr sector, E-F – Cueva Caon Verde, G – Cueva Zuna, H – Cueva Charles Brewer sector).


Fig. 51: Imperfectly developed “nger-ow” pillars, called “tetas” by cavers. These represent the upper funnels, and other remains of the pillars in this Cueva Muchimuk sector were insuciently lithied to be preserved. – Fig. 52: A – Two horizons with winnowed poorly-lithied arenites supported only by the “nger-ow” pillars in Cueva de Araas. B – Gran Galera Karen y Fanny in the Cueva Charles Brewer sector represents the world’s largest cavity in arenites and it is also one of the ten largest natural subterranean spaces in the world. The latest stages of its development are clearly dominated by rockfalls and gradual ceiling collapse. C, D – Laminated, soft, clay-rich arenites in the lower part of the Cueva Charles Brewer sector were responsible for the initial stages of this cave’s speleogenesis which was followeded by successive rockfalls.


. rf f – nfnr, n f Fig. 53: A, B – Collapsed linear caves in the Guyana part of Roraima. C, D – This collapsed huge cave space created the well-known Lake Gladys in the Guyana part of Roraima. E – Recent entrance to the Cueva Charles Brewer sector was created as a huge collapse. F – Large collapse zone in Chur Tepui. This collapse zone was most likely also inuenced by winnowing of poorly-lithied sediments, as shown by the inclined megablocks in the collapse zone.


from 18.08 to 45.75 in 52 measurements, with an average of 28.47, median of 27.17, and a standard deviation of 7.03. e derived uniaxial compressive strength ranged from 25 to 80 Mpa, with the majority of values below 60 MPa. It should be noted that the value of the derived uniaxial compressive strength increases with its increasing dispersion. e relatively high uctuations within this strength parameter are closely linked to the eect of hidden discontinuities in the rock massif interior. ese uniaxial compressive strength values show that most of the measured arenites ranged from weak sandstones to indurated sandstones, while the true quartzites with uniaxial compressive strengths above 200 MPa were rare at the measured sites (cf. Young et al., 2009: p. 22-24) (Fig. 58B). Mineralogy and petrology of arenites and red muds e Matau Formation is the topmost part of the Roraima Supergroup and it shows a wide lithication variability in its arenites. It ranges from loose sands through sandstones to very hard quartzites. e loose sands are least common, as they are rarely preserved due to erosion. e sandstones and quartzites dominate this formation and form the main mass of the tepuis, with the current proportion of individual types representing recent-stage relics remaining aer long-term weathering and erosion. It is presently unclear if this same ratio also applied to the eroded part of the formation (see Discussion). Our observa tions show that the recent remnants of the Matau Formation are dominated by quartzose arenites, and subordinately by arkoses and lithic to sublithic arenites (cf. White et al., 1966; Reid, 1972). e arenite grain size varies depending on original sedimentary conditions. Here, it ranges from very ne, well-sorted arenites which are mainly of aeolian origin to very coarse arenites and conglomerate layers, which are most likely uvial in origin (Fig. 59A-B). e aeolian origin of the ne arenites is indicated by well-abraded sand grains, and by cross-bedding with angles greater than 30 (Fig. 59C-F). Water-formed ripple marks are common on the cave ceilings and oors (Fig. 59G-H). Our research focused on beds with contrasting hardness on the formation’s surface and in its caves. e hardness correlates to the arenite lithication stage, and the contrast between the poorly lithied arenites and the overlying and underlying welllithied arenites, including “nger-ow” pillars, was so great that these two end-member lithologies had to be treated by separate methods. e samples from loose arenites usually disintegrated into individual grains and their mineralogical composition was determined by XRD, under binocular lens and SEM. e hard samples of well-lithied arenites were also studied in thinsections. e petrographic study showed that arenites were rst compacted. Compaction is the main lithication agent, common to all samples, including the poorly lithied arenites. e arenitic grains are tightly packed together, with common interlocked and jigsaw-like grain boundaries. is compaction caused partial mobilization of SiO 2 , and syntaxial rims grew into the free pores (Fig. 60). Cementation of the remaining pores in the aforementioned two end-members was dierent. e poorly lithied arenites showed no further cementation stages or else they were cemented only with kaolinite (Fig. 60E-F; conrmed also by the XRD results – see below). Table 3 provides an over view of the diagenetic phenomena in all examined lithotypes. e remaining porosity of the arenites from the overlying and underlying beds was lled with silica (Fig. 60A-B). e “ngerow” pillars mainly displayed quartz syntaxial overgrowths, pervasive silica cementation and some kaolinite (Fig. 60C-D). e SEM observation of some incompletely disintegrated grain clusters of poorly lithied arenites illustrated that the boundaries between the grains are still open, porosity remains high and the grain boundaries show no evidence of being formed by dissolu tion (Fig. 61A-B). In contrast, the well-lithied arenites show larger amounts of silica (Fig. 62A) and quartz (Fig. 62B-C) and their grain boundaries are mostly obliterated by cementation, with low subsequent porosity (Fig. 61C-D). It is important to note that there were no signs of quartz dissolution in any of the samples, and the quartz grains displayed no pits or notches typical of quartz dissolution (cf. Hurst, 1981; Hurst & Bjrkum, 1986). e only alteration observed was kaolinization of mica scales (Fig. 62D) and feldspar crystals (Fig. 62E). e XRD analysis was focused on both friable and lithied sandstones. Mineralogical constituents of samples from the – Fig. 54: A – The well-known depression El Foso on Roraima caused by cave collapse. Some remaining “nger-ow” pillars are visible at the bottom of the depression (arrow). B – Rests of the “nger-ow” pillars are also visible in Lake Gladys (arrow).


. rf f – nfnr, n f Fig. 55: A – Bizarre patterns on the surface of a sandstone block in the Cueva Charles Brewer sector which may have originated from microbial etching. B – Additional dissolutional forms found in Cueva de los Pmones (Ojos de Cristal Cave System). C – Bizarre weathering structures on quartzitic blocks form ing the collapse zone between Cueva Charles Brewer and Cueva Juliana. Their origin is uncertain. Their equal orientation indicates that they originated in a similar manner to photokarren described by Lundberg et al. (2010 b ). D-F – Pools with cyanobacteria on the surface of Chur Tepui. The shallow depressions could be due to etching from the cyanobacterial alkalization in this environment.


plateaus over the Cueva Charles Brewer and Cueva Colibr sectors are listed in Table 4. Samples of laminated friable sandstone come from the laminated sandstones of the beds with “nger-ow” pillars, and these were collected from the pillars themselves and also from the surrounding loose sandstone. Meanwhile, samples of lithied sandstones were collected from overlying beds of mas sive to laminated quartzites. e main mineralogical components of both types of sandstones are quartz and various clay minerals (Tab. 4; Fig. 63A-B). Although the samples analysed by XRD did not contain any feldspars, their presence was detected petro graphically in some other samples. Although clay mineral content diers in these sandstones, kaolinite and pyrophyllite are typical in all samples of the loosely lithied sandstones (Fig. 63A) while the well-lithied massive sandstones from the overlying beds of massive quartzite consist almost exclusively of pure quartz. e very weak shoulder between 18 – 28 2 may reect the presence of amorphous silica (opal-A) in the composition of sandstones lacking clay minerals (Fig. 63B; CK5-5). Pyrophyllite and traces – Fig. 56: A-D – Forms of leaking and the accumulation of lateritic products (“Barro Rojo”) in the studied caves. E – “Barro Rojo” can be black in some places. A,B,C,E – Cueva Charles Brewer sector, D – Cueva de los Pmones sector.


. rf f – nfnr, n f Fig. 57: A-F – Speleothem forms produced from lithied “Barro Rojo”. Note that the colour changes from red to black (A-B, F – Cueva Charles Brewer sector, C-E – Cueva Colibr sector). G – A broken “Barro Rojo” stalactite in the Cueva Charles Brewer sector revealing concentric structure with red and black laminae.


of kaolinite were also identied in the mineralogical composition of some samples from the lowermost parts of the overlying beds which possess a transitional composition (Fig. 63B; CK5-14). Mineralogical constituents of the red mud are listed in Table 4, and the main clay mineral identied by XRD is kaolinite (Fig. 63C). Minor amounts of pyrophyllite and quartz were identied in the mineralogical composition of the separated clay fraction (<2 m). e broader hump between 17 and 30 2 reects the presence of iron oxy-hydroxides, which are most likely poorly crystallized (Fig. 63C), and the identied diraction peaks reveal the presence of goethite. Particularly important is itacolumite, a special exible sand stone which commonly occurs in the Ojos de Cristal Cave Sys tem, and also in some parts of the Charles Brewer Cave System (Fig. 64A-B). Its exibility is possible due to lack of cement but interlocked quartz grains enable some movement (Dusseault, 1980). ere are several theories concerning this lack of cement, with some authors considering it to be a secondary characteristic caused by dissolution of clay minerals or micas (see Kerbey, 2011 for review). Only Suzuki & Shimizu (2003) have inferred that the missing cement is etched quartz cement. Microscope views show that clay minerals, presumably kaolinite, are present in the itacolumite specimen from the Ojos de Cristal System (Fig. 64CE). e possibility of dissolution of clay minerals is supported by the fact that itacolumite was sometimes connected with the discharges of red mud (Fig. 64F). However, thin-section and SEM studies make the whole genesis of itacolumite more com plex. At rst glance, thin-section shows no porosity preserved in the rock (Fig. 65A). However, under larger magnication, thin rims around the quartz grains are visible. In some places these appear empty (Fig. 65B), but in others they contain colour and extinguishing of neighbouring quartz grain (Fig. 65C). e rim is actually an empty space, and the gap noted in this laer instance is just masked by overlapping quartz grain edges. e empty spaces at the grain/grain boundaries are clearly visible under SEM (Fig. 65D-E). ese thin spaces between the grains are the reason for the itacolumite exibility. e SEM study also revealed that unlike other examined arenite samples, the itacolu mite specimen displays obvious signs of dissolution (Figs. 66, 67). in-lamellate phyllosilicates, which are most likely kaolinite, are also ubiquitous, thus conrming microscopic studies (Fig. 67). However, they rest on a substrate formed by quartz grains with etching, but the fact that they are intact indicates that the cement phase is secondary, post-dating the quartz etching. ere is no clear relationship between this etching and the aforementioned thin gaps between the quartz grains, and the grain boundaries bear no signs of irregularities caused by such etching. To the contrary, they appear to match each other, and this suggests an origin due to hydraulic dilatation. A similar process was inferred by Wirth (1989), who suggested that itacolumite originated from the overpressure of uids during heating of the quartz/kaolinite system to produce pyrophyllite and water. e common pres ence of pyrophyllite revealed in sandstone samples in our XRD analysis may substantiate this assumption. 2.6.4. Discussion Cement dissolution versus non-cementation Besides lava tunnels, which are especially common in basaltic lava volcanic areas, silicate caves are the most exceptional due to very low SiO 2 solubility (Hill & Forti, 1986; Wray, 1997 a,b , 1999). e novel results concerning speleogenesis described in this volume and in previous papers (Aubrecht et al., 2008 b ; Aubrecht et al., 2011) explain the cave-forming processes in arenites using examples from the two largest sandstone cave – Fig. 58: A – Diagram showing the dierences in hardness of poorly-lithied rocks, overlying and underlying beds and the “nger-ow” pillars at individual sites, measured by Schmidt hammer. B – Diagram showing relationships between Schmidt hammer rebound strength, bulk density and derived uniaxial compressive strength.


. rf f – nfnr, n f Fig. 59: A-B – Conglomerate layers in the Matau Formation on top of Roraima. These are most likely of uvial origin. C-D – High-angle cross-bedding in the Matau Formation in arenite beds on top of Roraima, highlighting their aeolian origin. E-F – Similar high-angle cross-beddings in Cueva de los Pmones. G-H – Ripple marks in the Matau Formation arenites showing their deposition in the aquatic environment. (G) Cueva Charles Brewer, (H) Cueva Juliana.


Fig. 60: Thin-section photos comparing diagenesis of the hard quartzites from the overlying and underlying beds of the poorly lithied horizons (A-B), “nger-ow” pillars (C-D) and the poorly-lithied arenites (E-F). Empty arrows point to syntaxial quartz overgrowths originated during the initial compac tion. Black arrows point to additional, later opal cement and triangular arrows indicate kaolinic, clay-mineral cement. These samples were taken from the top of Chur Tepui at the locality depicted in Figure 47A. –


systems in the world: the Charles Brewer and Ojos de Cristal cave systems. Most authors (e.g. Urbani, 1986; Galn, 1988; Piccini, 1995; Wray, 1997 a,b , etc.) explain the origin and evolu tion of the quartzite karst by chemical dissolution processes in various climatic conditions, combined with long-term exposure to chemical weathering. is model was even previously used by Galn et al. (2004 b ) for the Ojos de Cristal System (called therein the “Roraima Sur System”). e following theories have been advanced to explain the dissolution mechanism; (1) tem porarily increased alkalinity of the groundwaters caused by lateritic weathering (Marker, 1976); (2) local alkalization of the micro-environment caused by microbes (Bdel et al., 2004; Brehm et al., 2005; Barton et al., 2009); (3) quartz hydration to opal (White et al., 1966); (4) the change of quartz to opal by microbial activity (Vidal Roman & Vaqueiro Rodrigues, 2007); (5) hydrothermal alteration along bedding planes and fractures (Zawidzki et al., 1976; Szczerban et al., 1977); and (6) karstication via intergranular cement dissolution (Martini, 1979; Urbani, 1986; Briceo & Schubert, 1990; Doerr, 1999). Martini (2004) considered the newly formed rock so and prone to erosion, and he named it “neosandstone”. e results presented by our team show that quartz dissolution is not necessarily the main speleogenetic factor in the Venezuelan tepuis. e hardness measurements showed that the caves’ side walls and the beds under overhangs on the surface are really so, and the petrographic research showed that this soness may be primary. ere is an evident lack of the characteristic signs of quartz dissolution and the so and hard beds show dierent stages of cementation. While the so beds have compaction or cementation only with kaolinite cement, the harder beds also possess opal to quartz cementation. Meanwhile, itacolumite has obvious quartz etching which may have been caused by increased alkalinity due to lateritization. e secondary kaolinite cement resting on this etched quartz could be an intermediate product in the weathering chain: aluminosilicate-clay mineral-laterite. It is not currently clear, whether the thin empty spaces between the quartz grains were also caused by etching, but the matching grain/grain boundaries do no support this view. e “nger-ow” pillars also provide evidence of lithication dierences. ey occur not only in the cave systems investigated by our team but also in the caves on Kukenn Tepui (Doerr, 1999: g. 11), on sandstone terrains in other continents including South Africa (Marker, 1976: gs. 2, 4) and in collapsed caves, such as El Foso (Fig. 54A) or Gladys Lake (Fig. 54B). eir origin is obvi ously related to the main phase of arenite cementation in upper parts of the tepuis by descending diagenetic uids which converted the overlying and underlying beds to hard quartzite. Spliing of the uid front into “ngers” ensured that these uids did not ll the entire bed. Meanwhile, the strongly lithied overlying and underlying beds caused their isolation and protected the uncemented beds from further uid inltration. is premise is supported by the horizontal course of most of the caves, which have perfectly straight ceilings and oors and are almost rec tangular in cross-section. Other evidence are smooth surfaces of many “nger-ow” pillars. Martini (2004) summarized this arenization/neosandstone theory as ‘weathering rst, followed by mechanical removal of sand’. According to this idea, the beds in which the caves formed were originally well cemented, as in the other beds or else the dissolution may have occurred in lithied beds with higher porosity (Wray, 1999). If this was true, lithied portions of rock would change to unlithied rock gradually, and no sharp demarcation would be visible. is would certainly result in uneven tops and booms of the caves and also irregular pillar shapes. Assuming that the pillars were not formed by “nger-ow” diagenesis, but were only erosional remnants (or corrosional – see Doerr, 1999), these pillars should have shapes which are elongated in the ow direction, with many irregularities and projections. Such elongated pillars were already observed in some parts of the stream corridors, as in Cueva Colibr, and they are easily dis tinguishable from the true “nger-ow” pillars which originated diagenetically (Fig. 68). A secondary penetration of these “ngerows” to already weathered “neosandstone” is quite unlikely. Hydrogeochemical results also discredit quartz dissolution as an important cave-forming process in the examined caves (see Aubrecht et al., 2011 and the hydrogeochemistry chapter in this volume). e dissolution of quartz at room temperature is extremely slow and it occurs best in alkaline environments. Several authors including Briceo & Schubert (1990) and Pic cini & Mecchia (2009) proposed an arenization model involv ing the dissolution of the more soluble opal sandstone matrix. However, true, mature quartzite does not contain any matrix; it consists of a compact mosaic of quartz crystals and rims. Fol lowing Martini (1979, 2000), Chalcra & Pye (1984) and Wray (1997 b ), quartzite arenization is caused by quartz grain dissolu tion along the crystal joints, preferably along sediment joints and bedding planes. . rf f – nfnr, n f Tab 3: Table summarizing the diagenetic phenomena present in the investigated forms of arenites. arenite formation diagenetic feature jigsaw-like boundaries syntaxial quartz kaolinite cement opal cement poorly cemented arenites + + + underlying and overlying beds ++ ++ + ++ “nger-ow” pillars ++ ++ + ++


e poorly lithied quartzite samples showed no evidence of quartz cement remnants following dissolution. In addition, solution pits and notches on quartz grains were not observed in thin sections or under SEM as described by Burley & Kantoro wicz (1986) and Hurst (1981). In contrast to reports by Martini (1979, 2000), and Chalcra and Pye (1984), signs of quartz grain corrosion along the crystal joints did not appear in our thin sec tions. Consequently, quartz dissolution cannot be considered a dominant force or a trigger process in the speleogenesis of these examined caves. Fig. 61: A – SEM photo of kaolinite-cemented soft arenite (the same bed as Fig. 60E-F). Note the remaining pores are still open. B – Enlarged view of the previous. Kaolinite, forming tiny idiomorphic scales, is the only cement in this rock. C–D – SEM of the strongly lithied quartzite specimens from the top of Chur Tepui. Note that the remaining porosity is low and most intergranular boundaries have been obliterated. –


. rf f – nfnr, n f Fig. 62: A – Opal cement on the surface of quartz grain from strongly lithied quartzite from the top of Chur Tepui. B – Opal cement recrystallized to microcrystalline quartz and partly intergrown with the kaolinite (arrow). Sample from top of Chur Tepui. C – Microcrystalline quartz crystals originated by recrystallization of opal cement. The strongly lithied quartzite from top of Chur Tepui. D – Kaolinite (smaller scales, top) originating at the expense of mica (larger scales, bottom). The strongly lithied quartzite from top of the Chur Tepui. E – Grain of kaolinized feldspar from the surface of Roraima. F – Enlarged view of 62E, showing the feldspar kaolinization in detail.

PAGE 67 Importance of “Barro Rojo” Some examined arenites, such as arkoses and subarkoses, also contain aluminosilicate minerals. Here, they mainly comprise micas and feldspars and these aluminosilicates dissolve in the acidic waters much more easily than quartz does (cf. diagrams in Valeton, 1972, and experiments of Franklin et al., 1994). Weath ering of feldspars, micas and clays release more silica than does quartz dissolution (Young et al., 2009). For aluminosilicate min erals this dissolution, or weathering, is an incongruent process, so that insoluble remnants such as secondary minerals are also formed during the dissolution process. ese secondary minerals include various clay minerals such as montmorillonite, illite and kaolinite, as well as Fe and Al oxides and hydroxides. Resultant types of secondary minerals depend on pH, temperature and ion content of the water, as well as on the composition of the primary aluminosilicates. e presence of aluminosilicates, especially in the less lithied quartzite layers of tepui rocks, is apparent in both thin sections and SEM examination. Under such humid and warm tropical conditions, the combination of incongruent dissolution processes and silicate rock weathering results in laterite formation. White, heavily kaolinized arkosic arenites with red lateritic caps are common in the Gran Sabana, (Fig. 69A-B). e SiO 2 released by the lateritization process causes local hardening of laterites (Fig. 69C), or it can freely precipitate in the form of jasper. A great example is the famous Quebrada de Jaspe (Jasper Creek), approximately 35 km north of Santa Elena de Uairn (Fig. 69D-E), where the red colour portrays its lateritic origin. e red mud found in excessive quantities in the examined cave systems consists of goethite, kaolinite, illite, quartz and pyrophyllite, thus making it a true laterite. e mud accumulations currently in the caves are only remnants not removed by water, and therefore the original amount of red mud was obviously much higher. Strongly lateritized arkosic and also greywacke arenites occur in some parts of these caves. ese are prone to easy erosion (Fig. 70A-C) and they are so so that they are easily cut by knife (Fig. 70D). e continuing dissolution processes within the laterite bodies have a consider able inuence upon the water chemistry, but this is manifested only in the water dripping from the laterite bodies, as noted in the hydro-geochemistry chapter herein. At the pediment of the table-mountains, the stream waters are aected by the dissolu tion processes in arkosic arenites. An apt example of the results of such processes is silica concentrations of up to 3.4 mg.l -1 in Ro Carrao (Piccini & Mecchia, 2009). We therefore presume that lateritization within the existing cave passages is in its nal stages. e lateritization in the examined cave systems is a very impor tant process. It is responsible for up to 30% of the empty space, and can therefore obviously trigger speleogenesis. is view is not entirely new, and is shared by authors including Corra Neto (2000), who stated that the alteration of mica and feldspar to argillaceous minerals and hydroxides is a very important speleogenetic factor. Although his statement concerned caves with similar formation in Brazil, he did not emphasize its role with respect to the quartz dissolution. Yanes & Briceo (1993) also admied the role of feldspar weathering as an accompany ing process to the quartz dissolution. Iron-rich speleothems are common in the areas formed by sandstones (see the review in Young et al., 2009, p. 138-140), and other cave explorers have also reported their existence in Venezuelan tepuis (Dyga et al, 1976; Zawidzki et al., 1976). – Tab. 4: Overview of mineralogical composition in selected samples of sandstones and muds from various localities. The mineralogical composition was identied with the help of X-ray powder analysis (PXRD). Sample Locality Rock type Quartz Goethite Kaolinite Pyrophyllite Opal-A PCHB2-5 Cueva Charles Brewer friable sandstone + – + + – PCHB2-8 Cueva Charles Brewer friable sandstone + – + + – RP2-9 Cueva Charles Brewer friable sandstone + – + + – CK5-5 Cueva Colibr lithied sandstone + – – – ? CK5-6 Cueva Colibr lithied sandstone + – – + – CK5-10 Cueva Colibr lithied sandstone + – – + – CK5-14 Cueva Colibr lithied sandstone + – – + – CK5-16 Cueva Colibr lithied sandstone + – – + – BR001 Cueva Charles Brewer Barro Rojo + + + + – BR002 Cueva Charles Brewer Barro Rojo + + + + –


Lateritization not only creates empty subterranean spaces, but it also provides the great amount of dissolved SiO 2 necessary to form large opal speleothems. Feldspars and micas are much more soluble in acidic tropical waters, and with their much more rapid dissolution than that of quartz, they contribute to both, cave formation and speleothem-forming processes. Finally, the role of biologically induced dissolution should be mentioned, too. e role of dierent biological growths such as lichens, algae and cyanobacteria in sandstone dissolution and/or disintegration has been described in numerous scientic papers. e eect of lichen organic acids on chemical weathering has already been described by Viles & Pentecost (1994), Bjelland & orseth (2002), Duane (2006) and others. Although the solubility in this case was enhanced by creation of organic-silica complexes, more eective dissolution processes are most likely due to the cyanobacteria induced bio-alkalization. Bdel et al. (2004) explained exfoliation processes occurring in South Af rican sandstone by bio-alkalization caused by cryptoendolithic cyanobacteria. is type of exfoliation was not seen in sandstones on the Matau Formation. Brehm et al. (2005) investigated the inuence of the biolms created by cyanobacteria, diatoms and heterotrophic bacteria on the quartz surfaces on Roraima. ere they noted that the associated biolms can create a localized shi in the pH from 3.4 to more than 9, which is sucient for quartz dissolution. e quartz covered with biolm is partly perforated to a depth of more than 4 mm (Brehm et al., 2005). is process is also apparent on the surface through the forma tion of the typical small pools on the quartzite surface (Fig. 43A, 55D). e corrosion of quartz grains or pebbles is oen clearly visible (Fig. 43D). Dissolution of quartz, even when enhanced by microbe al kalization (Bdel et al., 2004; Brehm et al., 2005; Barton et al., 2009) as seen in solution pits on the table-mountains’ rocky surfaces plays a subordinate role in speleogenesis sensu stricto . However, if we concede that lateritization is a true dissolution process, the arenitic caves in the Venezuelan tepuis may be re ally ranked as karst. Descending diagenetic uid ow and possible origin of tepuis Summarizing the results of the speleogenetic research of our team, several important points surfaced concerning the origin of the tepuis. Although the research elucidated many aspects of the speleogenetic process, it also created new questions and problems. e most conspicuous nding was that the Matau Formation is formed not only by quartzites but that its arenites show various degrees of lithication. Our research provided evidence of variability in vertical proles. But what about the lateral variability? Are tepuis with a dominant presence of hardlithied quartzites typical examples of the Matau Formation? What about the larger, missing portion of the formation which was removed by erosion? Why are tepuis usually isolated islands rising up from the at Gran Sabana? And also, why there are no “ruins” of tepuis formed by accumulations of quartzite boulders dispersed throughout the Gran Sabana? Answers to these questions are currently purely theoretical as the missing, eroded portion of the Matau Formation can no Fig. 63: A – X-ray powder diraction (PXRD) pattern of friable sandstones from the plateau over the Cueva Charles Brewer sector. Prl – pyrophyllite, Kln – kaolinite, Qtz – quartz. B – A most representative PXRD pattern of the well lithied massif (CK5-5) and laminated (CK5-14) sandstones from the Cueva Colibr sector. The PXRD pattern of CK5-5 sample shows a very weak shoulder between 18 – 28 2; this may refer to the presence of amorphous silica (opal-A). C – PXRD pattern of samples of “Barro Rojo”. The broader hump between 17 and 30 2 may reect the presence of poorly crystallized iron oxi-hydroxides. Only presence of goethite (Gt) has been denitely conrmed. . rf f – nfnr, n f


longer be examined. However, knowledge gathered from our research of this formation’s remnants can be united under one common image which entails a new theory of the origin of tepuis. “Finger-ow” pillars in the arenites forming these tepuis indi cate that the descending ow of silica-bearing diagenetic uids provided induration of arenites to very hard quartzites. is ow penetrated deeply enough to lithify hundreds of metres of arenites in a vertical prole, and the indurated rocks then protected less lithied portions of the formation below. Most of the tepuis are limited by vertical clis, and undercuing of these clis oen occurs because the lower parts of the rock are less lithied (see also Young et al., 2009: p. 58-60). Undercuing and the subsequent rockfall are responsible for creation of the rock talus around tepuis (Montaas al pie del escarpado – see Fig. 64: A-B – Plates of exible sandstone (itacolumite) scaled from the cave ceilings (A – Cueva Juliana, B – Cueva de los Pmones sector). C – Itacolumite sample from Cueva de los Pmones sector seen under binocular lens. The sediment is formed by quartz grains (glassy), with remnants of clay-mineral ce ment (most likely kaolinite – white spots). D – Enlarged view of the previous, showing two intergranular voids with white clay-mineral cement (arrow). E – A further void with clay-mineral cement (arrow). F – A well scaled itacolumite plate covered with the “Barro Rojo” laterite in Cueva Juliana. –


Fig. 65: A – A thin-section view of the itacolumite sample showing quartz arenite with interlocked grains which apparently lack porosity. B – The thin inter granular empty spaces are revealed under higher magnication (arrows). C – An apparently lled space which is actually an overlap of quartz grain edges (arrow). D-F – SEM conrming the presence of thin empty spaces between the quartz grains in the Cueva de los Pmones sector, Ojos de Cristal Cave System. . rf f – nfnr, n f


Briceo & Schubert, 1992 b : g. 4.3). e talus then passes to at country surrounding the tepuis, without retaining any remnants of quartzite boulder accumulations. Moreover, closer inspection of the talus around Roraima indicates that it is formed by less lithied, so arenites of the Roraima Supergroup, which most likely underlie the sandstones and quartzites, rather than by fallen quartzite blocks (Fig. 71A-C). Erosion of these so arenites causes undercuing of the Roraima clis and keeps them steep. All these observations indicate that the patchy distribution of tepuis in Gran Sabana was formed long ago by vertical lithi cation of the Matau Formation. is lithication required a voluminous source of soluble SiO 2 and sucient uids. Exactly as expected today, the best source of SiO 2 then was the clay and rocks with micas and feldspars above the Matau Formation. ese were easily aected by lateritization, which most likely occurred aer the Late Carboniferous, when the northernmost Fig. 66: A-D – Signs of dissolution of quartz grains in the itacolumite sample. The rectangle in A marks the area which is enlarged in B. –


Fig. 67: A – Newly-formed phyllosilicate minerals (most likely kaolinite) resting on the etched quartz grains (clearly visible in the upper left part of the photo). The rectangle indicates the area enlarged in the next photo. B – Enlarged phyllosilicate minerals from the previous photo. C – Unknown clay miner als with very small crystals (in the rectangle – enlarged in D) resting on the etched quartz grains. Newly formed, euhedral quartz grains are present in the centre of the photo. These grains most likely formed from recrystallization of silica cement. D – Enlarged clay minerals from the previous photo. Itacolumite sample, Cueva de los Pmones sector, Ojos de Cristal Cave System. . rf f – nfnr, n f


part of South America reached the tropical zone (see Scotese, 2001). e best source of uids would undoubtedly have been water reservoirs on the surface, and thus the recent distribu tion of tepuis may have copied the distribution of ancient lakes and rivers (Fig. 72). Alternative explanations for the erosion of the missing portions of the Roraima Supergroup include the inference of Galn et al. (2004 a : g. 1) that this erosion mainly aected tectonically disrupted parts of the Roraima Supergroup. However, this contradicts the lack of boulder accumulations on Gran Sabana. Moreover, the disrupted parts of the Roraima Supergroup had to be more widespread than the undissected ones, and this is considered most unlikely. is theory is currently based on a limited set of data and further research is necessary. Although new data may support or refute our theory, it is very satisfying to provoke future research in this area. 2.7. SPELEOTHEMS 2.7.1. Introduction Speleothems are special cave formations caused by secondary mineral deposits and are generally ubiquitous in limestone caves, since the rates of dissolution and reprecipitation of calcite and aragonite are relatively high (Appelo & Postma, 2005). However, caves formed in silicate rocks such as the caves in the Venezuelan tepuis contain siliceous speleothems instead (Urbani, 1976, 1996; Webb & Finlayson, 1984; Vidal Roman & Vilaplana, 1984; Wray, 1999; Lveill et al., 2000; Willems et al., 2002; Forti et al., 2003; Cioccale et al., 2008; Vidal Roman et al., 2010). Siliceous speleothems are usually small, rarely exceeding 2 cm in size (e.g. Webb and Finlayson, 1984). e mineralogical composition of the siliceous speleothems is quite simple, since they all consist of various types of opal, mainly opal-A, opal-CT or quartz. In addition to this, the opal may also contain various enclosures of minerals such as kaolinite, dickite, sepiolite, or gypsum (Webb & Finlayson, 1987; Wray, 1999; Forti et al., 2003). Interestingly, these siliceous speleothems share many structural similarities with the siliceous sinters precipitated from hot springs (Jones et al., 2001 a ; Konhauser et al., 2001; Konhauser et al., 2003). In contrast to most carbonate speleothems, the precipitation of siliceous speleothems is oen mediated by microbes (e.g. Wil lems et al., 2002; Urbani et al., 2005; Urban et al., 2007; Aubre cht et al., 2008 a ). is feature is also common in the hot-spring siliceous sinters (Jones et al., 2001 b ; Jones et al., 2002; Jones et al., 2003), but the prevailing hypothesis is that the hotspring siliceous sinters might contain other biotas (e.g. a high amount of autotrophic cyanobacteria) than the siliceous speleothems. It is a well established fact in paleontology that siliceous microbialites are generally typical features of the Precambrian era and that they provide evidence of early prokaryotic life. Several studies have been dedicated to the comparison of microbial communities in Archean time and the recent hot-spring siliceous sinters (e.g. Konhauser et al., 2003). Examination of siliceous speleothems may therefore provide an interestingsupplementary approach to explore the siliceous stromatolites that originated from nonphotic environments. Furthermore, in the longer context, such studies may also provide interesting models for research into the biology and evolution of extremophiles (organisms living under extreme conditions) as well as for astrobiology in general, since many extreme cave or karst systems may serve as models for how life might appear on other planetary bodies such as Mars (Lveill & Daa, 2009; Lee et al., 2012). e Charles Brewer and Ojos de Cristal cave systems, which are separated from each other by a distance of about 200 km, contain many types of speleothems (Carreo & Urbani, 2004; Aubrecht et al., 2008 a,b ). Most of these are siliceous speleothems, consisting of virtually all minerals generally encountered in siliceous speleothems, from amorphous opal-A, through opalCT to microcrystalline quartz (chalcedony). However, there are also non-siliceous speleothems in these caves, such as the desiccated “Barro Rojo” (consisting mainly of goethite – see speleogenesis chapter – 2.5.). It is important to note that the term “non-siliceous” used in this context denotes speleothems which originate from materials other than silica, although they may contain some silicate minerals, such as kaolinite and py rophyllite. In addition, other minerals have also occasionally Fig. 68: Erosional pillars formed by owing water can be easily dierentiated from the “nger-ow” pillars by their elongated shapes parallel to the stream course, Cueva Colibr sector, Charles Brewer Cave System. –


been identied in the explored caves including gypsum and sanjuanite (see section 2.7.4.). ese speleothems were formed in dierent ways: some were most likely formed by inorganic precipitation from water solutions, while others represent only insoluble residua (e.g. “Barro Rojo” – see section, but the vast majority of the speleothems do appear to bear signs of microbial mediation during at least some stages of their development. Interestingly, most of these speleothems represent the largest known cryptic stromatolites grown in cave habitats, and the largest siliceous stromatolites in non-aquatic environments (Aubrecht et al., 2008 a,b ). Generally, the Charles Brewer Cave System contains larger speleothem formations than the Ojos de Cristal Cave System. A plausible explanatation for this may be the obvious size dierences between these two cave systems and, conse quently, dierent amounts of dissolved SiO 2 . In this subchapter, we describe the research performed so far on various types of speleothems (non-microbial versus microbial siliceous spe leothems) in more detail. is description was suported by the mineralogical and petrographical methods normally used in Fig. 69: A – The white kaolinic weathering crust developed on the Roraima Supergroup arkosic arenites, capped by a red lateritic weathering crust. Sierra de Pakaraima at the Venezuelan/Brazilian border. B – Lateritic weathering crust with the remnants of kaolinite at Sierra de Pakaraima. C – Remnants of silicied laterites are typical for the Gran Sabana area. D-E – Jasper layers precipitated from silica emanating from lateritic processes. Quebrada de Jaspe (Jasper Creek). . rf f – nfnr, n f


analysis of speleothems, comprising thin-section, SEM and XRD studies, together with dierent types of biological investigations. Unfortunately, these studies have only currently been performed on a limited number of samples, because great caution has been taken to prevent excessive damage to the speleothem decoration of the caves during various expeditions. erefore, almost all samples used for these studies were taken from speleothems which were already detached from the surface or partly damaged by previous cave visitors. Although the number of samples may produce some biased results, nevertheless each item of informa tion is paramount in gaining a rst glimpse into the origin and composition of these speleothems. Based on these results, we hope that future sampling can then be planned more eciently for more penetrating, holistic studies. Fig. 70: A-C – Soft lateritized greywacke arenites with evolved erosional forms in the Cueva Colibr sector (Charles Brewer Cave System). D – Lateritized arenites are so soft that they can be cut by knife. Cueva Caon Verde. –


Fig. 71: A – A view on Mt. Roraima (and Mt. Kukenan – left). The mountain consists of quartzites, which form steep clis (C) and surrounding talus (T). B-C – The talus is not formed only of fallen quartzite blocks but mostly of soft, uncemented arenites prone to erosion. Photos from the tourist access trail to Roraima. . rf f – nfnr, n f


2.7.2. Inorganic siliceous speleothems In this subchapter, we describe siliceous speleothems that are generally not obviously mediated via microbes or other organ isms, but which may occasionally contain or become inuenced by organic material. Although non-microbial speleothems are rather rare in the Charles Brewer and Ojos de Cristal cave systems, their shapes are very similar, diering only in their average size. Siliceous stalactites Stalactites are one of the most common forms of non-microbial siliceous speleothems in the examined caves (Fig. 73). e vari ous stages of their development can be observed in slabs of old mature stalactites (Fig. 74). In their initial stages, they form mostly smooth, soda-straw-like stalactites (Fig. 73A-B; see also Carreo & Urbani, 2004: p. 33) hanging from the ceilings in cave areas where SiO 2 -saturated, or semi-saturated, water drips down. Un like limestone speleothems, these usually do not have stalagmitic counterparts on the ground, and only planar owstone crusts cover the substrate (see the following section e struc ture of these speleothems can change over a period to bizarre, atypical forms, reminiscent of carrots and turnips, rstly with regular wavy constrictions (Fig. 73C-D), and later with a pustular surface (Fig. 73E-F). Analysis of cross-sections of such speleo thems indicated that these structures were caused by uneven precipitation of silica directly on the stalactite before dripping and forming small cascades, overhangs, lumps and bulbs (Fig. 74A-B). e more uneven the surface, the longer the trajectory of the water drop becomes, so that the water most likely evaporates before it reaches the stalactite tip. is phenomenon therefore oen induces a nely-laminated inner structure (Fig. 75A-B). Although non-recrystallized opal is the main component of these stalactites, relatively long needle-like gypsum crystals can also occasionally be found in them (Fig. 75C-D). Some stalactites can also contain a rich sandy admixture, so that agglutinated sandy stalactites may form when excessive sand is present (Fig. 74C-D). Flowstone crusts Flowstone crusts are from several mm to 1cm thick. ese are usually laminated (Fig. 76A) and a gradual recrystallization of originally amorphous phases to quartz can be observed on some of them (Fig. 76B). Microscopic observations show that most analyzed specimens are characterized by spheroidal forms, with undulose, fan-like extinguishing in crossed polars (Fig. 76C). is may indicate that the transformation is still an ongoing process, most likely transforming from opal-CT to chalcedony. e individual spheroids are usually very nely laminated (Fig. 76D), possibly due to the diagenetic oscilla tion of opal with various water contents (see Jones & Renaut, 2004). Speleothems as a whole are commonly zonal due to the numerous opaque inclusions that form the above-mentioned lamination. Under microscope examination, some speleothems show bizarre structures including numerous voids, or alveolar “bubbles” (Fig. 76E). Some voids are lled by younger, nonrecrystallized generations of silica compounds, and needles of currently unidentied, low-birefringence mineral enclosed in silica are commonly observed (Fig. 76F). ese speleothems may also contain occasionally sand accumulations, or they might even become combined with microbial speleothems (e.g. overgrown by stromatolites). “Cobweb stalactites” (teleraas) “Cobweb stalactites” occur in both examined cave systems. ey do not represent truly inorganic speleothems as they are formed via opal encrustation of spider webs hanging from the ceilings (Fig. 77). e very ne structures of some “cobweb stalactites”, Fig. 72: The newly proposed model of the origin of the tepuis. A – The Roraima Group was originally capped by sediments rich in micas, feldspars or clay minerals which were prone to lateritization. This lateritization may have begun in the Late Carboniferous when the northern part of present South America reached tropical areas (Scotese, 2001). B – The lateritiza tion occurred mostly in the areas with excess uids, such as rivers and lakes. The descending uids brought silica from the lateritization zones downwards, causing additional cementation of the Matau Formation. This cementation was patchy, and concentrated only in the zones with sucient water. C-D – In the later geomorphological evolution stages, the uncemented portions of the Roraima Supergroup were subjected to erosion and the cemented, quartzitic parts were preserved, together with the softer, uncemented parts protected below them. The steep clis of the tepuis are maintained by erosion of the softer, uncemented arenites below with subsequent undercutting of the quartzite layers. –


. rf f – nfnr, n f Fig. 73: Typical evolution of inorganic opal stalactites. The initial stages are straight, soda-straw-like stalactites (A-B), which attain more bizarre forms with wavy constrictions (C-D), and later with irregular pustules (E-F). Cueva Charles Brewer sector (Charles Brewer Cave System).


Fig. 74: A-B – Slabs showing longitudinal cross-sections through two specimens of inorganic opal stalactites from the Cueva Charles Brewer sector (the specimens were not in growing position as they were already detached from the substrate). The growth zones highlight the irregular formation of the speleothems, attaining more and more bizarre shape with elongation of the trajectory of the water droplets. C-D – Mixed, sandy-opal stalactites may form in the excess of free sand grains. Cueva de los Pmones sector (Ojos de Cristal Cave System). –


with tips commonly inclined towards the air draught, imply that their encrustation was not caused by seeping water but more likely by aerosols (Fig. 77F). One reason for this is that seeping water would make the cobweb too heavy, and consequently it would hang more vertically from the ceiling. Microscopic studies of cobweb stalactites showed that these structures are almost exclusively characterized by a laminated opal form, resembling columnar stromatolite but of inorganic origin (herein we consider stromatolites as being exclusively of biogenic origin). Four dierent growth subzones can oen be distinguished in the speleothem specimen (Fig. 78): the middle zone (m), central zone (c), alveolar zone (a), and outer zone (o). e middle and central zones are discontinuous in 2-D view, possibly caused by initial scrolling of the stalactite during its growth. e middle zone consists of brownish (colours as they appear in thin-section), cloudy to semi-opaque, non-laminated opal. In contrast, the central zone consists of nely laminated opal (resembling siliceous stromatolite) which is much clearer and transparent. Under higher magnication, thin spider threads can be observed in the laer two zones (Fig. 78B). Since these laments are very thin and discontinuous and oen extend be yond the plane of the thin-section, this may indicate that they are linear rather than planar bodies, and therefore they represent threads rather than tiny fractures. e alveolar zone is formed by laminated opal, which is cloudy in some places with numerous alveolar to globular voids resem bling fenestral pores in intertidal limestones and dolomites (Fig. 78C-D). A rich sandy admixture can be observed with the spider threads in this zone. e outer zone is predominantly composed of clear, or some times turbid nely laminated opal. In some places, the lamination is convex from the stalactite, giving the appearance of an inward growing stromatolite (Fig. 78D). Spider threads are present in this zone, which also contains considerably less fenestral pores and detrital sand grains. In some other samples of “teleraas” the non-microbial opal encrusting spider threads may also be combined with some microbial, stromatolitic zones. . rf f – nfnr, n f Fig. 75: Microphotos of the inorganic opal stalactite. A,B – Fine-laminated structure of the stalactite. C,D – Thin needle-like gypsum crystals in the stalactite (C – plane polarized light, D – crossed polars).

PAGE 81 Mineralogical composition of siliceous speleothems e mineralogy of speleothems in sandstone caves does not vary as much as for those in granitic caves, which can contain opalA, evansite, bolivarite, struvite, pigotite, tanarakite, allophane, hematite or goethite in dierent areas (Webb, 1976; Macas Vsquez et al., 1980; Hill & Forti, 1995; Forti et al., 2003; Vidal Roman et al., 2010). Although speleothems from the examined sandstone cave systems show dierent forms and types, their mineralogy is quite uniform. ese samples usually exhibit a concentric or botrioidal texture in thin section. Needle-like crystals with low interference colours were detected in samples of speleothems with concentric structure (Fig. 76F). Due to their small size it was not possible to identify them, but the low birefringence of these minerals indicates that they could repre sent barite or apatite. ere were also some higher-birefringence needles, which most likely represented gypsum (Fig. 75C-D). XRD paerns of the speleothems were compared with pub lished data, and mineralogical identication and characterization of impurities enclosed in the opal was also performed. According to X-ray powder diraction results, all analyzed speleothems had a large hump centered at approximately 4.0 in a paern typical for opal-A (Jones & Segnit, 1971; Floerke et al., 1991; Graetsch, 1994). In addition to opal-A, there was also quartz in some samples, likely some of this was detritic (Fig. 79A). e opal-A samples from the studied speleothems dier in FWHM index (listed in Tab. 5). e FWHM index was not cal culated for samples containing quartz, because the broad hump in opal-A coincides with quartz diraction peaks. An approxima tion of the structural state of a particular opaline silica sample is available from the FWHM index of the above-mentioned distinctive 0.4 nm diraction line or band (Herdianita et al., 2000). is method is analogous to the one used to measure clay crystallinities (Moore & Reynolds, 1997). SEM images of samples from the studied sandstone caves re vealed the presence of smooth silica spheres typical for opal-AG (Fig. 79B-C). ese opal spheres are commonly elongated and oen imperfectly shaped. ey are also disordered, and dier in size in the range of from 1 to 2 m. e freshly broken surfaces of selected samples showed none of the concentric layered spheres reported by Darragh et al. (1966) and Gaillou et al. (2008). Siliceous speleothems were also analyzed using Raman spec troscopy in thin section and freshly broken chips. A typical fea ture of all the analyzed samples was a high level of uorescence which eectively swamped any Raman photons. When bands were observable, these tended to be broad and ill dened, and therefore their interpretation was not possible. Since some of the uorescence background appears to reside in the disordered and amorphous state of opal-A itself (Sple et al., 1997), the obtained Raman spectra most likely represent opal-A. Moreover, the uorescence of opal-A may be caused by the presence of specic chemical compounds such as aluminum or iron. Despite the opal strong uorescence, the most characteristic Raman signals identied quartz (Fig. 80A-B). Quartz was con rmed by the presence of most characteristic Raman signals (Fig 80B). Subsequently, the obtained spectrum of quartz was compared with the published data, and it correlated perfectly ( – R040031, Kingma & Hemley, 1994). Ac cording to these results it appears that quartz is a very common “inclusion” in the examined opal speleothems. 2.7.3. Biospeleothems In this subchapter we describe speleothems mediated via microorganisms. Most of these represent true stromatolites as described in the literature, with the latest overviews being contained in the volume edited by Reitner et al. (2011). Unlike most of the stromatolites described previously, stromatolites in these two examined large cave systems mostly did not form in an entirely aquatic environment. As such, they are unique and deserve a detailed description. Many bizarre biospeleothem forms were discovered in both the Charles Brewer and Ojos de Cristal cave systems, thus high lighting the striking similarities between these two systems. ey were found in many dierent locations in the caves, especially close to owing water systems, and there were vast quantities in all cave zones, from well illuminated entrance zones to com pletely dark inner ones. One of the most common forms encoun tered was mushroom-shaped speleothems, sometimes termed “dolls” (Spanish: muecos – Fig. 81A-B). ese are over 10 cm high, and their main features are the white stems and dark brown caps. However, there are also several other forms, such as the “black corals” (Spanish: corales negros), characterized by a more bizarre, branching shape (Fig. 81C-E), and also “gucimos” which have branching shapes, but otherwise resemble muecos (Fig. 81F). All these are coralloid speleothems types, which are the most common types of speleothems encountered in silicate caves in other parts of the world (Swartzlow & Keller, 1937; Urbani, 1976; Zawidzki et al., 1976; Wray, 1999; Cioccale et al., 2008). Many of the biospeleothems in the Charles Brewer and Ojos de Cristal cave systems are oen found in amazingly large ar rangements on bedding-planes, joints and the lower sides of overhanging quartzite beds. ese may be lined up in massive numbers of ball-shaped speleothems called “champignons” (Fig. 82A-G), or in kidney-shaped speleothems (Spanish: rin – Fig. 82H), or other mushroom-like speleothems (Fig. 83A-C). Some of these “champignons” are hollow, with a thin crust on their top, which may have originated from the encrusting parts of a microbial mat unaached to the previous microbial layers (Fig. 82G). Some stalagmitic forms also resemble ice-creams (Spanish: helados – Fig. 83D-E). Older, strongly lithied champignonlike speleothems prevail in the Ojos de Cristal Cave System, including stalactites with strange shapes similar to wide cones (Fig. 83F), while others have surfaces with bizarre paerns re sembling panther fur (Fig. 83G). is laer type is also present in the Charles Brewer Cave System. “Muecos”, “corals” and “champignons” are the most com mon forms of biospeleothems in the Charles Brewer and Ojos de Cristal cave systems, and although most resemble the classi cal stalactites and stalagmites in limestone caves, they dier in structure and origin. Despite their bizarre and variable shapes, the microbial speleothems oen show a common principal tex ture corresponding to various stages of their evolution (Fig. 84). ey consist of the following two main components, commonly –


occurring in the same speleothem; 1) a laminated columnar stromatolite, consisting of non-porous compact opal which forms most of the speleothem internal zone; and 2) a strongly porous stromatolite formed by white chalk-like opal, which appear to contain an accumulation of microbial-like peloids, usually form ing the outer speleothem zone. In some biospeleothems, these zones are irregular and can alternate, or else they can occur separately, thus forming spe leothems consisting exclusively of one type of microbial struc ture. For some currently undiscovered reason, samples from the Charles Brewer Cave System contain both types of microbialites, whereas those from the Ojos de Cristal System have only the Fig. 76: A – Inorganic, drapery-shaped opal owstone crust. Cueva Charles Brewer sector. B – Old owstone crust recrystallized to quartz crystals in the Cueva de los Pmones sector. C-F – Microphotos of the owstone crust from the Cueva Charles Brewer sector. C – This fan-like undulatory extinguishing of the owstone crust in the thin-section indicates the initial recrystallization of originally amorphous opal. This stage may represent opal CT. D – Very ne spheroidal lamination in the owstone may be caused by oscillating contents of water. E – Bizarre alveolar bubbles trapped in the siliceous owstone. F – Newly formed low-birefringence needle-like crystals in the owstone, depicted in the centre of the photo. . rf f – nfnr, n f


porous or peloidal type (see below). Since this laer nding may be caused by insucient sampling, a columnar stromatolite-type presence in the Ojos de Cristal System cannot be excluded. Detailed observations of the anatomy of both types of stro matolites were performed by petrographic, thin-section study, and also by SEM study of fresh, broken, cut or hydrouoric acid (HF) etched speleothems. Longitudinal thin-sections through various specimens of microbial speleothems revealed that their inner structure usually mainly consists of the two principal types (Fig. 85A); the branching, ne-laminated columnar stromatolite (s) and the porous peloidal stromatolite (m) form the majority of the “mueco” specimen. ese are accompanied by athin, ne-laminated outer stromatolitic zone (o). Columnar stromatolites from the Chur Tepui caves samples are nely laminated, with alternating laminae of clear and brown ish opal (Fig. 85B-C), which appear alveolar in cross-section (Fig. 85D). Dense bundles of radial laments formed by microbial builders are clearly apparent in these stromatolites (Fig. 86A-C), and spherical enclosures, most likely of organic origin, can be found trapped in some parts (Fig. 86D). Apical portions of the “black coral” and “gucimo” samples from the Cueva Charles Brewer sector, which most likely represent the Fig. 77: A-E – Various forms of cobweb stalactites (“teleraas”) originating from encrustation of spider threads by opal. F – Due to the supporting ne cobweb structure, the speleothems are often inclined in the direction of the draught. A-B – Cueva Charles Brewer sector, C,F – Cueva Caon Verde, D,E – Cueva Colibri sector. –


active, living/evolving parts of the columnar stromatolite, appear under SEM as bizarre, branching, coral-like bodies (Fig. 87A-D). It is likely that other animals, especially spiders, contributed to these structures, since spider-like threads can oen clearly be seen emerging from the opal (Fig. 87E). ese are readily distin guished from the fungal hyphae which are usually thicker, curved and branching (Fig. 87F). In situ eld observations in the Cueva Charles Brewer sector revealed considerable spider activity, not only on the “cobweb stalactites” but also on stalagmitic forms. Some of the observed growth planes of these speleothems appear to be agglutinated from detrital material (Fig. 87G-H). SEM study of etched surfaces of the ne-laminated columnar stromatolite showed that it consists mainly of thin concentric laminae (Fig. 88). Most of the lamination appears to be related to the presence of microorganisms, since many densely packed, parallel tubular casts of lamentous-like microbes can be ob served (Figs. 88, 89). is is also supported by thin-section petrographic studies. However, it is also possible, for example, that at least some of the laminae may be of abiogenic origin, precipitated directly from water. e abundance and distribu tion of the microbial and abiogenic laminae vary within the speleothems (Fig. 89C-F). SEM study of the lamentous-like microbes shows that their tubes are 50-80 m long, straight and unbranched. ey have cir cular cross-sections, measuring 5-10 m in width. In longitudinal section these appear as simple tubes, but small remnants of septa Fig. 78: Thin-section images of a “cobweb stalactite” from the Cueva Charles Brewer sector. A – Scanned overview image of a longitudinal thin-section of a “cob web stalactite”. The letters indicate zones: middle (m), central (c), alveolar (a) and outer (o). B – Spider threads (arrowed) preserved in the clear opal of the central zone. C – Alveolar zone (longitudinal cross-section), bordered by central (c) and outer (o) zones. Note the bizarre fenestral pores and quartz sand grains trapped within this zone. D – Convex stromatolitic ospur (arrows) projecting inward from the outer zone, implying the possible inward growth of the entire stalactite. . rf f – nfnr, n f


Fig. 79: A – X-ray powder diraction patterns of various opal speleothems. Some opal speleo thems contain only one mineral, but some also include quartz (Qtz) or gypsum (Gp). B-C – SEM image of opal-AG spheres. – Fig. 80: A – The Raman spectra of opal speleothems are inuenced by strong uorescence which eectively swamped Raman photons. This strong uores cence is characteristic for opal-A with certain amount of aluminum or iron. B – Raman spectra of quartz grains which occur as inclusions in speleothem opal.


are visible on their inner surfaces (Fig. 90). e spaces between the septa are regular at approximately 2.5 m. ese structures may represent the same microbes that form the surface alveolar bodies observed on the unetched speleothem surfaces of SEM prepared specimens (see above – Fig. 87). Irregular, and oen oval-shaped double-layered cross-sections of silicied microbe tubes were revealed within some parts of the columnar stroma tolite (Fig. 91). eir diameters are more variable than those of the previous casts, ranging from 10 to 35 m. In other parts of the stromatolite, the etching revealed network-like structures (Fig. 92A), which are also likely related to microbial activity and which contribute to formation of the columnar stromatolites alveolar zone. Etching of the columnar stromatolite also revealed other, sheet-like structures trapped in the opal. ese structures showed certain similarities to remnants of plant tissues or the chitin of insect remnants (Fig. 92B). e porous peloidal stromatolite in both cave systems con sists of relatively uniform ovoid peloids (Fig. 93A-D), which are densely packed and arranged in concentric laminae. Near the columnar stromatolite, they are usually packed more loosely, with interstitial pores lled with pure opal. e size of the peloids ranges from 0.1 to about 0.3 mm. In some places, well-dened peloid areas connect to areas of obliterated peloidal structure which resemble mud-cracks (Fig. 93E). In some parts of the “champignon” samples from the Cueva Charles Brewer sector, larger spheroidal bodies, with irregular sizes varying from 250 to 520 m, can be observed (Fig. 93F). In the central zone of the “mueco” specimen, the peloidal structure is disturbed by fenestral shaped pores and trapped quartz sand grains. Some silicied organic remnants, which appear as thin tubes and tube meshworks are apparent in the central zone. ese may be ali ated to trapped insects, spiders or plant remnants (Fig. 94A-B). Similar structures have also been found in some speleothems in the Ojos de Cristal Cave System (Fig. 94C). A common structure in many of the speleothems is the chitin remnants of arthropods, ranging from common insects to spiders, and even scorpion exuvia (Fig. 94D). Unlike columnar laminated stromatolites, the peloidal types are usually less cemented. Stronger cementation was frequently observed in the samples from the Ojos de Cristal Cave System (mainly from the Cueva de Gilberto sector) but more rarely in the samples from the Charles Brewer Cave System (the Cueva Charles Brewer sector). e well-cemented peloidal microbial ites are usually older, as shown by Lundberg et al. (2010 a ) who estimated that the age of “rin” (see the specimen in Fig. 82H) lies between 290-390 f. e peloids of most of the younger samples studied via SEM are predominantly loosely packed, with open pores between the peloids (Fig. 95A-C). When these structures become cemented and the boundaries between the peloids are obliterated, some porosity usually remains (Fig. 95D-E). To determine the portion of porosity in the speleothems and the ability of capillary forces to moisturize the speleothems, we invented the simple staining experiment of dipping the boom part of longitudinally cut “mu eco” into ink for one day. e gradual rise of the liquid was then documented by aseries of photos. is procedure showed that the ink reached the extreme apical part of the speleothem aer several hours, and even its surface became wet (Fig. 96). Interestingly, this simple laboratory experiment explains the eld observation of wet speleothem surfaces with drops of water on the tips, in caves where humidity was not excessively high. In some cases, even a small amount of water is sucient to moisten an entire small speleothem up to 10 cm in height and to provide water to non-encrusted organisms, such as bacteria residing on its surface. Tab. 5: Overview of identied mineralogical composition of opal speleothems analyzed by X-ray powder diraction. The FWHM (full width at half maxi mum) index was calculated using Wint software for all samples. Cueva Charles Brewer sector. Sample Opal type Other minerals Calculated d-spacing [nm] Peak position (rCuKf) FWHM index Ven-1 opal-A – 0,415 21,417 2,098 Ven-2 opal-A – 0,416 21,351 2,391 Ven-3 opal-A – 0,416 21,377 2,355 Ven-4 opal-A – 0,411 21,621 2,747 Ven-5 opal-A – 0,416 21,366 3,780 Ven-6 opal-A – 0,414 21,490 3,008 Ven-7 opal-A – 4,168 21,319 5,229 Ven-8 opal-A Qtz – – – Ven-9 opal-A Qtz – – – . rf f – nfnr, n f


Fig. 81: The most common forms of stalagmitic microbial speleothems: A-B – “Muecos”. C-E – “Black corals”. F – “Gucimo”. A,B,D,F – Cueva Charles Brewer and C – Cueva Colibr sectors, E – Cueva Juliana. – Fig. 82: Various forms of champignon-like microbial speleothems. A-D – “Champignons” in Cueva Charles Brewer sector. E – “Champignons” from Cueva Juliana. F – “Champignons” in the Cueva Colibr sector. G – Some “champignons” are hollow, with thin crusts preserved on top, Cueva Charles Brewer sector. H – An old, well-lithied specimen of a champignon-like speleothem called “rin” (kidney speleothem), Cueva Charles Brewer sector. This specimen was analyzed and dated by Lundberg et al. (2010 a ).


. rf f – nfnr, n f


Fig. 83: A-C – Additional examples of mushroom-like microbial speleothems from Cueva Charles Brewer sector. D-E – Ice-cream-like speleothems (“hela dos”), Cueva Charles Brewer sector. F – Old, well lithied microbial speleothems with shapes of wider truncated cones in Cueva Ojos de Cristal sector. G – Strange microbial speleothems with their surfaces resembling panther-fur pattern, seen in the Cueva Charles Brewer sector. –


. rf f – nfnr, n f Fig. 84: Slabs showing the internal structure of microbial speleothems from Cueva Charles Brewer sector. A – “Mueco”, B-C – “Champignons”, D – “Rin” (the same specimen as in Fig. 82H), E – “Gucimo”. The principal common structure consists of columnar stromatolite (s) formed by lamentous microbes with white, chalky peloidal stromatolite (p) formed by Nostoc -like microbes.


e internal structures of peloids are oen obliterated by pro gressive diagenesis and contain less microbial-like structures. e peloid surfaces from the inner, well lithied parts show only tiny irregular spherules (Fig. 97A-B). Internal microbiallike structures can only be identied aer scraping away the outer, less silicied zones. A similar observation is apparent in thin section examination of the outer zones. e peloids and also larger spheroidal bodies consist of short microbial laments which usually have a uniform cell size, with 1.3-1.4 m diameter (Fig. 97C-F, 98), although larger cells 1.8-1.9 m in diameter are sometimes present (Fig. 98C). ese cells bear a certain resemblance to heterocysts normally associated with nitrogen xing Nostoc -type cyanobacteria (cf. Fig. 99). e microbial structures can also be observed by SEM, although the inner structure is less clear here due to silica encrustation (Fig. 98D-F). Fig. 85: A – Scanned longitudinal thin-section of the “mueco” specimen from the Cueva Charles Brewer sector (see Fig. 81A). The zones visible in thin-sec tion are: s – columnar stromatolites, m – laminated peloidal microbialites, and o – outer stromatolitic zone. B – Longitudinal cross-section of the columnar stromatolite. C – Another image of the columnar stromatolite showing alternation of ne laminae of brownish and clear opal. A speleothem with a pantherlike pattern on its surface in the Cueva Charles Brewer sector. D – Tangential cross-section of columnar stromatolites showing alveolar-like structure. –


White mats on the rock surfaces were commonly observed in both examined cave systems. ese represent initial colonization of the surface by the microbes that form the peloidal zones of the speleothems (see previous paragraph). In the initial stages, they form mats (Fig. 100A), shrubs (Fig. 100B-C) and also irregular swarms (Fig. 100D) which cover the underlying arenites. e similarity between this kind of microbe and those from the pe loidal speleothem types was microscopically veried (Fig. 100E). While the microbial laments are commonly encrusted with white silica, the surrounding arenites remain intact. is may be an indication of microbial mediation of the silica precipitation (cf. Aubrecht et al., 2008 b ), caused either by microbe metabolism or modied physico-chemical conditions. While such microbial mediated processes can oen be observed in limestones, it was unclear if this is also valid for silica precipitation, so this has been widely debated (see overview in Konhauser, 2007). 2.7.4. Non-siliceous speleothems In addition to the siliceous speleothems, a wide range of nonsiliceous speleothems, including gypsum, pigotite, evansite, struvite, taranakite, goethite, sanjuanite and natrolite have been reported in dierent silicate caves (Webb, 1976; Macas Vsquez et al., 1980; Hill and Forti, 1995; Forti et al., 2003; Vidal Roman et al., 2010). Some of these can also be observed in both our cave systems. A short overview on currently observed non-siliceous speleothems in the explored cave systems is now provided. “Barro Rojo” Since the mineralogical composition and macroscopic forms of this speleothem type were covered in the speleogenesis chapter (2.6.), this section concentrates on its microscopic characteris tics. Red mud (“Barro Rojo”) stalactites are relatively so and therefore it is quite dicult to prepare thins-sections from them. In the thin-sections which could be prepared for microscopy studies, the laterite oen appears laminated and is either brown or black in colour. Although it was not possible to distinguish any obvious microbial-like forms in these kinds of stalactite samples, microscopy examination of a temporary preparation of an unlithied “Barro Rojo” mud from the Charles Brewer Cave System revealed ubiquitous forms similar to the cell strings seen in the peloidal zones of other speleothems (Fig. 101A-B). In . rf f – nfnr, n f Fig. 86: A-C – Filamentous microbes in the columnar stromatolite visible under higher magnications. D – Spherical enclosures trapped in the stromatolite. These are most likely of organic origin. Cueva Charles Brewer sector.




Fig. 87: SEM images of the surface of “black coral” (Cueva Charles Brewer sector). A – Surface of “black coral” formed by bizzare stromatolitic bodies, pos sibly representing a surface with protruding lamentous microbes. B-D – Enlarged alveolar surface from the previous photo, resembling tiny coral bodies. Thin spider threads emerging from the speleothem are also visible. E – Another part of the surface of the growing portion of the “black coral” with spider threads emerging from the opal surface. F – Branching fungal hyphae visible on the speleothem surface. These are thicker than the spider threads. G-H – Surface of the growing part of the speleothem formed by agglutinated detritic material. . rf f – nfnr, n f Fig. 88: A-I – SEM views on lamentous microbe casts from columnal stromatolites from the “mueco” specimen (see Fig. 81A). Cueva Charles Brewer sector.


addition to these, numerous thin, green lamentous structures could also be observed (Fig. 101A-D) and the laterite itself forms tiny globules among meshworks of these laments (Fig. 101C-D). e green laments appear as small twisted tubes under SEM (Fig. 101E-F), and these remnants’ morphology has similarities to stalks of Fe-oxidizing bacteria Gallionella ferruginea (see e.g. Ridgway et al., 1981; Kim et al., 2003; Schieber & Glamoclija, 2007; Hofmann et al., 2008). It is most likely that these microbes do not play an active role in the early stages of lateritization such as decaying phyllosilicates and feldspars, but they may possibly become active in the nal, iron-oxidizing stages. Gypsum Gypsum (calcium sulphate – CaSO 4 .2H 2 O) is a common cave mineral in all normal limestone caves (Hill & Forti, 1986) but it also occurs in silicate caves (Sanjurjo et al., 2007; Vidal Roman et al., 2010), and has also been reported from arenitic caves on tepuis (Forti, 1994) Mineral samples which range from the needle to platy or coralloid morphology (Fig. 102A-B) and the brous to earthy aggregates sampled in the studied cave systems were subjected to basic mineralogical study based on powder X-ray diraction. is study revealed that two distinctive minerals could be distin guished in these samples. e rst group includes needle to at or coralloid-like mineral aggregates which showed a distinctive powder X-ray diraction paern. ese paerns are typical for gypsum (Fig. 102C). Although various gypsum crystal morpho types show a large diversity, as discussed above, in most cases all analyzed aggregates appear mono-mineralic (Fig. 102C). Further studies, based for example on stable isotopes, are required to provide a more detailed understanding of these speleothems. Isotopic study of sulphur can reveal its potentional source. e examined arenites mostly lack sulphur and there were no signs of hydrothermal activity. On the other hand, presence of bio logical activity in the cave systems infers that the sulphur may be of biogenic origin. Sanjuanite e second group of non-siliceous minerals includes needle-like or brous to earthy aggregates (Fig. 103A-B), mostly of white colour. According to the X-ray diraction paern, they consist of associations of sanjuanite – Al 2 (PO 4 )(SO 4 )(OH).9(H 2 O) and gypsum (Fig. 103C). So far, this mineral has only been detected at a few localities around the world (see e.g. Abeleedo Fig. 89: Filamentous microbe casts from columnar stromatolites in the “mueco” specimen. Note that some laminae are inorganic, formed by pure silica (C-F). Cueva Charles Brewer sector. –


et al., 1968 who described sanjuanite from plant-bearing slates located on the ridges of Sierra Chica de Zonda and San Juan Precordillera). e veinlets of sanjuanite are oen bounded by thin gypsum layers, and sanjuanite occurs as white, chalklike compact masses with dull to silky lustre. In comparison, sanjuanite from the arenitic caves appears as white, brous or earthy aggregates, which are oen friable. e association of sanjuanite and gypsum has also been observed in samples from the studied arenitic caves (Cueva Charles Brewer, Cueva Colibr – Charles Brewer Cave System) where they usually ap pear as small, several centimetre-sized aggregates with sharp boundaries. ese aggregates are usually oval and are chaotically distributed in the deeper levels of the caves. Although the main elements of sanjuanite are sulphur and phosporus, it is almost certain that they do not originate from hydrothermal activity. Instead, it is more likely that these two elements came from . rf f – nfnr, n f Fig. 90: Details from lament casts showing regular septate structure. Cueva Charles Brewer sector. The white rectangle in C depicts the area enlarged in D. Note that some septae in the casts are oblique to the lament orientation. This is apparent in the centre of D.


Fig. 91: Irregular double-layered cross-sections of tubes representing casts from dierent lamentous microbes. “Black coral” (A-B) and mushroom-like speleothem (C-D), Cueva Charles Brewer sector. – Fig. 92: A – Irregular network structure contributing to the formation of the alveolar zone of the columnar stromatolite. B – Sheet-like structures protruding from the opal. These most likely represent remnants of plant tissue or chitinous insect remains. “Black coral” specimen in the Cueva Charles Brewer sector.


. rf f – nfnr, n f Fig. 93: A – Concentric laminae of peloids in the peloidal zone of the “mueco” specimen (Cueva Charles Brewer sector). B – Detailed view of these peloids. C-D – Similar peloidal stromatolites are also typical in champignon-like speleothems at Roraima (Cueva de Gilberto sector). E – View of portion of the pe loidal zone, with the structure replaced by mud-crack-like appearance in the “mueco” specimen. Cueva Charles Brewer sector. F – Spheroid bodies in the “champignon”. Together with peloids, these mostly resemble spherical bodies formed by Nostoc colonies. Cueva Caon Verde Cave.


organic residues such as guano or from an accumulation of dead animal bodies, such as insects. However, this hypothesis needs further exploration based on a wide eld of studies, including mineralogical and geochemical analyses. 2.7.5. Discussion Speleothem size Siliceous speleothems are ubiquitous not only in Venezuelan caves, such as in the Roraima Supergroup (Zawidzki et al., 1976; Urbani, 1976, 1996; Forti, 1994; Urbani et al., 2005), but also in silicate caves throughout the world (e.g. Webb & Finlayson, 1984; Wray, 1999; Lveill et al., 2000; Gradziski & Jach, 2001; Willems et al., 2002; Forti et al., 2003; Urban et al., 2007; Vidal Roman et al., 2010). Although the silicate speleothems in the Venezuelan cave systems are rather unique, they show certain resemblances to other silicate spelothems, and particularly to the coralloid speleothems rst described by Swartzlow & Keller (1937). However, the greatest majority of siliceous speleothems currently described in silicate caves outside Venezuela have been rather small specimens, and they mainly represent owstones several millimetres thick. e only exception so far is the 28 cm opal column from Bilemat Kul lava cave in Korea (Hill & Forti, 1986: p. 105). In con trast to silicate caves in other parts of the world, the silicious speleothems in the Cueva Charles Brewer sector, for example, oen exceed 10 cm in length and can reach up to 50 cm. Al though the speleothems from the Ojos de Cristal Cave System are somewhat smaller, usually not exceeding 10 cm, they are still larger than the average speleothem size in silicate caves in other parts of the world. A quite plausible explanation for this dierence in size between the silicate speleothems in the Charles Brewer and Ojos de Cristal cave systems compared to other world silicate caves could be that these two Venezue lan caves are currently the largest described sandstone cave systems on Earth. Logically, the large cave size will be able to – Fig. 94: A-C – Silicied relics of organic structures trapped in the speleothems. These are most likely from arthropods or plants; A-B – “Mueco” specimen, Cueva Charles Brewer sector, C – Mushroom-like microbial-sandy speleothem (Cueva Ojos de Cristal sector). D – Accumulation of scorpion exuvia encrusted by silica in the Cueva Charles Brewer sector.

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. rf f – nfnr, n f Fig. 95: A – Etched surface of the “mueco” specimen revealing the peloidal layer. These peloids and the porosity between them are well preserved, but the microbial structures are obscured. Cueva Charles Brewer sector. B-C – detailed view of the previous sample. D – Part of the peloidal layer underwent stronger opal cementation, but its considerable porosity is still preserved. “Black coral” in the Cueva Charles Brewer sector. E – Part of the stronger lithied peloidal stromatolite, with deformed peloids which resemble mud-cracks in cross-section. Cueva de Gilberto sector. Fig. 96: Results of experiments from staining the “mueco” slab with ink. It is obvious that the liquid is able to penetrate the pores in the peloidal layer by capillary force to the height of the speleothem’s apical portion. Only the central columnar stromatolite, mostly formed by compact silicite, remained less coloured. Cueva Charles Brewer sector.

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provide larger volumes of dissolved and re-precipitated SiO 2 over a period of time. However, more detailed future studies are required to conrm if there is a signicant correlation between cave size and speleothem size. Despite these large cave dimensions, the growth rate of various types of siliceous speleothems, including the microbial speleothems, is very low. Lundberg et al. (2010 a ) concluded that the maximum growth rates of speleothems are 0.370.23 mm/ka. is indicates that approximately 270.000 years is required for a speleothem to reach a height of 10 cm! – Fig. 97: A – SEM images of the peloidal layer of the “black coral” sample showing loosely packed ovoidal peloids. The rectangle marks the portion enlarged in the next photo. Cueva Charles Brewer sector. B – Enlarged view of the peloid in the previous photo. Irregular tiny spherules are visible on its surface. C-E – Gradually enlarged views of peloids from the outer layers of the “champignon” specimen (Cueva Charles Brewer sector) revealing microbial structure of peloids. These peloids are formed by short-lamentous microbes which have a meshwork arrangement. F – A further enlarged view of these peloids.

PAGE 102 Sources of silica Four principal types of natural sources contribute silica com pounds to speleothem formation. e two following can be regarded as primary; subterranean rivers and water seeping from the surface, while two additional sources can be derived from these: water spray and condensed moisture on cave walls. Our current hypothesis is that the two laer sources serve as the main agents for distribution of silica to the speleothems, since most of them are beyond the reach of owing water, and dissolved silica concentration in subterranean streams and seeping waters . rf f – nfnr, n f Fig. 98: A-B – Strongly enlarged thin-section views of the peloids from the outer zones of the “champignon” specimen, showing detailed appearance of the microbes. Cueva Charles Brewer sector. C – Similar view, revealing also some enlarged cells (heterocysts) in some microbial strings (yellow arrow). D – SEM view on the detached peloid from the outer zone of the “champignon” specimen. E-F – Details of the previous sample revealing meshwork of the microbial laments. However, the inner structure of microbes is not visible under SEM.

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is quite low (see Ipia, 1994; Lnczos et al., 2007; Aubrecht et al., 2008 b , 2011; and section 2.5. in this volume). is hypothesis is further supported by hydrogeochemical analysis of the small pools of dripping condensed water. is showed that despite low overall concentrations of dissolved substances, silica concentration there is considerably higher than in all other measured water sources (see the hydrogeochemistry chapter; section 2.5. herein). Based on this, we propose that the mechanism for the speleothem development is initiated by a “hydrocorrosive action” of the condensed water on surfaces, which will then induce a regular release of sand grains over a period of time. ese sand grains are then transported via drop lets or small streams of this water onto the speleothem surfaces irrespective of whether these are dripstones or erected forms. is hypothesis may provide a simple explanation for several mysterious phenomena, such as why so many sand grains can be found on the speleothems (some of these might even have been formed via agglutination of sand grains), and why so many speleothems can be found even under the ceilings of large gal leries. is is also a proof that “arenization” is really present, but only in mature stages of the speleogenesis. Another possible strong silicifying agent could also be the water released from lateritization, as indicated by analysis measured in pools which are formed in “Barro Rojo”. Although generally undersaturated with respect to SiO 2 , the primary water owing and seeping from the surface can also be an important source of silica as evaporation occurs. Generally, silicication can result from evaporation of any kind of water, regardless of how high the initial concentration of dissolved silica is. Evaporation modies the cave waters’ hydrochemistry signicantly, so that the concentration of dissolved compounds can increase in the small isolated pools over a period of time. is evaporation can then also act on the speleothems themselves. e dye experiment reported in section 2.7.3. herein showed that the peloidal layer can serve as an excellent conduit for water and that capillary forces are strong enough to provide moisture to most of the speleothem volume, even when only a small volume of water is available (Fig. 96). is moisture can therefore not only support growth of microbial mats, but its evaporation from speleothem surfaces also causes precipitation of SiO 2 over a period of time. Fine water spray and aerosols which pervade the caves’ at mosphere can also provide an equally perfect source of silica. ese aerosol droplets cannot be observed with the naked eye but they can be revealed on photographs using a ash light (Fig. – Fig. 99: Images of living Nostoc colonies for comparison purposes. A-B – Normal soil Nostoc colony cultivated in lab (compare it with Fig. 98A-C). C – Macroscopic view of spherical Nostoc colonies. D – Spherical Nostoc colonies in Laudachsee Lake, Austria.

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104). Evaporation of tiny spray droplets can greatly increase the silica concentration, and this process is most likely the main contributor to the development of the “cobweb stalactites” (see also section e ne structures of these special stalactites with tips inclined towards the air draught imply that their encrustation was not due to the seeping water, but rather to aerosols because seeping water would have make the cobwebs so heavy that they would have hung more vertically from the ceiling. Geomicrobiology During the last decades, concepts of the potential role of dier ent types of organisms in caves expanded signicantly. ese include micro-organisms, and also macro-organisms such as fungi and smaller animals. Although it is acknowledged that some types of organisms and communities have contributed signicantly to cave developmental processes, including the formation of speleothems, our knowledge of these processes remains extremely limited (Lee et al., 2012). . rf f – nfnr, n f Fig. 100: A – Silica-encrusted microbial mats represent the initial microbial colonization on the cave walls. Cueva de los Pmones sector. B-C – Detailed views of the initial microbial colonization of the rock substrate. The microbes are arranged in regular shrub-like formations. Note that the white coloured silicication aected only the microbes, and not the surrounding quartzite. Cueva Caon Verde. D – Another view of the initial microbial colonization, lacking regularity in its lament arrangement. Cueva Charles Brewer sector. E – Collage of microphotos of the microbial cell strings from the microbial mat highlighted in the previous photo. The laments strongly resemble those in the outer layers of the “champignon”.

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Many of the speleothems observed in the Charles Brewer and Ojos de Cristal cave systems appear to contain or be associated with several forms of organisms. ese range from various meta zoan species, including spiders and insects which can be observed directly with the eye, to various other morphological types of microorganisms. ese laer types span from multicellular for mations such as lamentous bacteria to single coccoid or rod-like cells which may or may not be aggregated. eir precise role is not currently understood, especially whether they contribute to speleothem formation, and if so, do they play an active role, or – Fig. 101: Microphoto and SEM images of the “Barro Rojo” sample (Cueva Charles Brewer sector). A-B – Some enlarged photos reveal the presence of microbi al cell strings similar to those in Fig. 100E). C-D – The main portions of this sample show a mixture of lateritic red globules and short, thin greenish laments. E-F – SEM view of the greenish laments. The laments have the appearance of twisted tubes, similar to the stalks in Gallionella ferruginea Fe-bacteria.

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they are only coincidentally associated with the speleothems? Irrespective of this, many speleothems in the Charles Brewer and Ojos de Cristal cave systems have recently been termed “biospeleothems”, due to the unusually high number of organ isms in or around them (see the section 2.7.3.). Interestingly, similar observations and speculations have been made about at least some of the siliceous speleothems observed in other parts of the world. Some of those studies have clearly recognized the predominantly microbial origin of siliceous speleothems (e.g. Forti, 1994; Urbani, 1996; Lveill et al., 2000; Willems et al., 2002), but only afew have provided information concerning their microbial composition. Unfortunately, the few performed studies have used various approaches, so it is dicult to make system atic comparisons or to currently draw any indisputable general conclusions about the geobiology of siliceous speleothems. e rst microbiological study of opal speleothems in sand stone caves was performed on those in caves on Sarisariama (Cueva de los Gucharos – Kunicka-Goldnger, 1982). Here, only classical methods were applied to the organisms which could be cultured. However, although approximately only 1 % of all bacte ria in the environment are culturable and only limited information was available from these classical methods, several interesting results were obtained. e four types of physiological groups involved were; i) heterotrophic bacteria such as Arthrobacter , Corynebacterium , Bacillus and Pseudomonas ; ii) nitrogen-xing species including the Azotobacter ; iii) cellulolythic species such as Cytophaga; and iv) autotrophic bacteria including nitrifying species andthe sulfur oxidizing species iobacillus ferrooxidans . Although no in situ studies were performed to conrm the func tion and explore the extent of the various physiological processes, the results in this study do at least support the indication that the main trophic mode of life of Cueva de los Gucharos microbial communities appears to be adapted to decaying bat and bird excrements and fruit remnants from their diets. However, these results cannot be used to explore further detailed hypotheses about their potential role in cave speleogenesis. Several studies have also reported dierent types of photo trophic organisms, such as diatomaceans and cyanobacteria, in certain types of siliceous speleothems and opal sinter deposits in hot springs and geysers (Jones et al., 2001b; Konhauser et al., 2001, 2003) in other parts of the world. ese occurred, for example, in caves of Japan and USA, where speleothems were located close to the cave entrance (Kashima et al., 1987; Kashima and Ogawa, 1995). . rf f – nfnr, n f Fig. 102: A-B – Gypsum aggregates from the Cueva Charles Brewer sector. The gypsum needles are approximately 10-12 mm long. C – X-ray powder dirac tion patterns of the brous to earthy aggregates composed of gypsum. Quartz was detected in signicantly lower quantities.

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e most recent study employing modern molecular methods on siliceous speleothems in the Ojos de Cristal Cave System on Roraima (called there Roraima Sur Cave) was performed by Giarrizo et al. (2009). A large range of dierent types of 16S rRNA gene sequences aliated to various bacteria groups were examined in this study. Although the function of some of these groups is unknown, there were also the following groups which showed aliation to bacterial groups with known function, such as hydrogen and methane oxidizing bacteria ( Methylocella , Methylosinus and Methylocystis) , dierent bacterial species in volved in the nitrogen cycle, heterotrophs which degrade com plex organic substrates such as Rhodopseudomon, iron oxidizing bacteria ( Rhodomycrobium), anoxygenoic phototrophic species including Oscillochloris and also the neustonic species including Nevskia, which trap compounds such as ammonia directly from the air. Although more detailed studies are needed to explore the function and activity of the various groups detected so far, it is obvious that bacteria involved in the nitrogen cycle form one of the most important parts of the ecosystem, since nitrogen is an essential element for all organisms. e bacteria involved in the nitrogen cycle in the Ojos de Cristal Cave System involve both nitrogen xing bacteria ( Rhizobiales ) and dierent types of nitrogen oxidizing bacteria (ammonia, nitrate and nitrite oxidi zers, including representatives of Planctomycetales ). Although this indicates that the ecosystem there is extremely complex, none of the currently detected microbial groups can be assigned with certainty to any direct involvement in silicate speleogenesis or the speleothem-forming process. Our microbiological research has focused mainly on dierent types of microscopical analysis enabling elucidation of detailed morphological characteristics within and between some of the various speleothems described in the Charles Brewer and Ojos de Cristal cave systems. is process provided initial insight into the overall morphological diversities in the various spe leothems. While the benet of thorough microscopical analy sis lies in obtaining detailed morphological structure, a major disadvantage is that only limited information can be obtained with regard to identity, function and activity. Morphology is an ambiguos indicator of biogenicity, even in these lamentous morphotypes (Ruiz et al., 2002; Hofmann et al., 2008). Despite this, our microscopical studies have proven to be most valuable for systematic comparison of the dierent types of speleothems from both the Venezuelan caves, and also in samples containing similar structures from other parts of the world. Several dierent – Fig. 103: A-B – Sanjuanite aggregates from the Cueva Colibr sector. C – X-ray powder diraction pattern of a sanjuanite sample. In addition to sanjuanite, gypsum was also detected in the mineralogical composition of the white earthy and brous aggregates.

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types of conjecturable information has been brought to light which will hopefully stimulate future research in geobiology, palaeontology and also astrobiology. Several dierent morphotypes have been detected thus far in various types of siliceous speleothems. A very obvious feature in many of these speleothems is their dierent types of lamentous morphotypes. Some of these most likely represent either fungi or spider webs, as was mentioned in various sections, including 2.7.3. Others could possibly represent lamentous microbes, which played a past or currently sustained role similar to that of the lamentous bacteria in dierent types of stromatolites microbial mats (Golubic, 1976 a ). Interestingly, Hofmann et al. (2008) recently reported that lamentous bacteria seem to be a rather common phenomenon in fossilized samples from various types of terrestrial/karst environments in dierent parts of the world. Although it is dicult to provide clear evidence for either biogenic or non-biogenic origin of these lamentous structures, several parameters similar to those in our studies indicate that at least some of those lamentous structures may have been formed by biogenic lament encrustration. Characteristics of the lamentous microbes forming the central columnar stromatolite in Charles Brewer Cave Sys tem speleothems remain uncertain. However, based simply on morphological criteria, they bear resemblance to heterotrophic sulde-oxidizing bacteria such as Beggiatoa, iron oxidizing bacte ria and also to phototrophic lamentous cyanobacteria. All these possibilities are realistic as these species are oen encountered in microbial mats and even in dierent types of stromatolites and other speleothem types in caves which date from the earliest evo lutionary life on Earth (Hofmann et al., 2008). It is impossible to precisely determine these species based solely on morphological criteria, especially when they have been obliterated by silicied remnants and casts (Jones et al., 2001 b ; Konhauser et al., 2003, Konhauser, 2007). Nevertheless, the opportunity to explore the similarities and dierences to investigated species in similar systems is quite benecial. Astonishingly, certain associations can be made to other microbial species. Simple septate tubes found in columnar stromatolites resemble Phormidium or other representatives of the Oscillatoriales order (Golubic, 1976 b : p. 135), and double-walled tubes, which are most likely sheathed, resemble either Cyanostylon (see Golubic, 1976 a : pl.I, g. 5), or Entophysalis from the order Chroococcales (Golubic, 1976 b : p.117). e diagonal septae in the lament casts (Fig. 90D) indicate the possibility that the lament could be twisted, as is typical in iron-oxidizing bacteria such as Gallionella . A more detailed identication is not possible because only a few morphological features were discernable in currently produced microscopical preparations. In this regard, Castenholtz (2001) stated that ap proximately 37 dierent characteristics are required for cyano bacteria optimal identication. e morphology of microbes forming the peloidal zones of the examined speleothems from these cave systems is less am biguous, because here they bear many features indicative of nostocalean cyanobacteria. e presence of phototrophic species such as cyanobacteria in these caves is not as surprising as one would expect. Several studies have already described cyanobacteria such as Geitleria calcarea , Scytonema julianum and Nostoc in both illuminated and pitch-black zones in caves, as well as in other dark ecosystems (Friedman, 1955; Bourrely and Depuy, 1973; Vinogradova et al., 1998). Furthermore, cyanobacterial species such as Nostoc, Fisherella and Calothrix can easily adapt to a heterotrophic life– style (as recorded in Whion, 1987) and some cyanobacterial species are even light sensitive (Vincent and Roy, 1993; Quesada and Vincent, 1997). ese have to protect themselves from light by either producing protective pigments in extracellular sheaths (e.g. Lyngbya estuarii produces scytonemine – Kylin, 1937), or else by digging deeper into the substrate, such as endolithic bor ing cyanobacteria Hormathonema and Hyella (Golubic, 1976 a ). Cyanobacteria’s nitrogen xing ability is most relevant in the normally nitrogen-poor environment of dark caves. Nostoc is also easily adaptable to a heterotrophic life-style, and is acommon endobiont in lichens and higher plants (Hoek et al., 1995). In addition to photosynthesis, it can also adapt to nitrate xation. In symbiosis with higher plants, Nostoc provides them with ni trogen (Graham & Wilcox, 2000). Only afew heterocysts were detected in our research and this suggests that the cyanobacteria may have grown in anitrogen-rich environment and were not nutrient stressed. However, further analysis using methods, such as molecular screening, are required to verify if these structures are indeed cyanobacteria. e restricted number of microbial morphotypes mentioned above indicates that the diversity of microbes participating in speleothems construction is much poorer than that on the top of Chimant Massif, especially regarding cyanobacteria (Ahti, 1992). e Nostoc -like microbes which form the peloidal stro matolites are not necessarily solely accumulations of cyanobac teria, because the peloids in which the Nostoc -like laments are concentrated are too regular in size and too regularly arranged to consist only of a random accumulation of Nostoc spheres. While there appears to be a higher-level order than just isolated microbial colonies, it cannot be excluded that Nostoc may sim ply be symbiotic there with other organisms such as fungi (for comparison see Schler et al., 1994, 2007). . rf f – nfnr, n f Fig. 104: Fine spray and aerosol droplets from waterfalls, which are nor mally visible only under ash light. Cueva Charles Brewer sector.

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One obvious remaining enigma is the phenomenon of the biologically mediated silica precipitation which occurs on the microbial-like laments while the surrounding rock remains intact. Although it has several times been proposed in litera ture that cyanobacteria protect themselves from excess silica encrustation by thickening their sheaths (see Konhauser, 2007: p. 186), our observations indicate that their presence actually promotes this silicication. Silicication in the examined Ven ezuelan arenitic caves takes place under normal temperature conditions, and this contrasts with the silicication conditions of the microbial assemblages observed in hot springs (Jones et al., 2001 b ), and also in experiments by Oehler (1976), where he simulated encrustation of cyanobacteria under high-temperature conditions. Although our observations indicate biological media tion of silicication, it is not yet clear whether this silicication is caused by microbial metabolism or by products from their decay. We are therefore currently employing various molecular bio logical, cultivation and activity targeted methods (e.g. micro calorimetry – Braissant et al., 2010) to pursue this question. So far, it is clear that: i) dierent bacterial and fungi species can be isolated from the speleothems (unpublished data – Fig. 105, Tab. 6); ii) dierent amounts of nucleic acids can be isolated from various speleothems (Tab. 7); and iii) that the diversity resulting from molecular analysis is considerably higher than that gleaned from standard microscopic analysis presented in earlier sections (unpublished results, Lee and Aubrecht). e diculty now lies in assigning a possible role to this microbial diversity. is is very important in distinguishing between past and present speleothem-forming encrusted microbes and the non-speleothem-forming microbes which possibly played an indirect role in overall speleogenesis by providing nitrogen for the speleothem-forming bacteria. Alternatively, some microbes may just have been temporary contaminants. At the moment, it is a great challenge to prove current mi crobial activity by molecular based methods, such as mRNA, which target clear indicators of microbial activity. Part of this problem can be assigned either to low microbial numbers and activity and/or to the eld conditions which were unable to assist optimal sampling for such analysis. Fortunately, there are other methods, including microcalorimetry, which can ex plore in situ activities directly. Initial aempts to employ this method on six various speleothems from various regions of the Venezuelan caves clearly demonstrated that at least some of the speleothems show signicant microbial activity, while others do not (unpublished results; Braissant et al., 2010). is could indicate that the role of microorganisms in speleothem develop ment diers in dierent types of speleothems. It is apparent that a broad holistic scientic approach is necessary to explore the validity of the hypothesis that microorganisms are involved in silicication of speleothems in these Venezuelan caves. Such an holistic approach may distinguish; i) obligate microbiota associ ated with the speleothems from other microbiota with dierent functions, irrespective of whether or not they are contaminants; and ii) past and present microbial processes. e ultimate proof of microorganism impact on silicication lies in retrieving actual isolates where this impact can be illustrated in vitro in the labo ratory, in a similar manner to those calcite precipitating isolates retrieved from stalactites in carbonate caves (see e.g. Baskar et al., 2006; Lee et al., 2012). Cobweb stalactites. Siliceous speleothems most likely formed by spider thread en crustation have, to our knowledge, never previously been re ported in the literature, although spiders and insects have oen been sighted in many types of caves (Lee et al., 2012). Spiders are especially ubiquitous in the Charles Brewer Cave System because many insect species are there, either autochthonous or introduced by the river owing from the surface. Although spi der threads primarily served as a supporting framework during speleothem growth, their presence has been recorded not only in “cobweb stalactites” but also in numerous other speleothems, such as “dolls”, “gucimos” and “black corals”. is phenomenon is highlighted in SEM photos, and especially in Figure 87E. – Fig. 105: Examples of agar plates containing dierent bacterial morphotypes from dierent types of bio-speleothems. The photos show the early stage of an ongoing isolation procedure made directly from the biospeleothems. See further explanations in Tab. 6. A – Isolates from the biospeleothems CLP1 and CLP2. B – Isolates from the biospeleothems CChB1 and CJ1. C – Isolates from the biospeleothems CK8 and CChB-6.

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2.8. CONCLUSIONS 1. Speleological, geological, geomorphological and hydrogeo chemical research was performed in the two largest sandstone cave systems in the world – the Charles Brewer Cave System (17.8 km) in the Chur Tepui and Ojos de Cristal Cave System (16.14 km) in Mt. Roraima. Unlike most of the previously ex plored sandstone cave systems in Venezuela, these consist of subhorizontal caves. e Charles Brewer Cave System consists predominantly of large, mature cave spaces. However, several younger, smaller caves were located at deeper levels. e age of this system is apparent from the numerous collapses which result ed in recent discontinuity of the previously well-interconnected system. Meanwhile, the Ojos de Cristal Cave System is a com plex labyrinth of younger, smaller caves which remain relatively well-interconnected due to their younger evolutionary stage. 2. e research revealed that quartz dissolution did not play a substantial role in the formation of these cave systems. Erosion of non-cemented layers and lateritization of arkosic arenites with dissolution of feldspars and micas proved to be more important, while any quartz dissolution noted played only aminor role. is is quite apparent in the lack of dissolutional features on the quartz grains. Although water condensed on the cave walls proved to be the main quartz-dissolving agent, it could not have been a trigger for cave-formation because it appeared only aer the cave space was created. 3. Soer beds in which the caves were initially formed showed a lack of cementation, or only kaolinite cementation, while the hard overlying and underlying beds and the “nger-ow” pillars are cemented by opal and quartz. ese “nger-ow” pillars which penetrate the non-cemented arenite beds and ceilings and booms of the initial caves are smooth, free from irregularities, and they supply further evidence of thecontrast ing dierences in cementation. . rf f – nfnr, n f Tab. 6: Table showing preliminary results from ongoing isolation attempts of bacteria and fungi from 11 dierent biospeleothems, on agar plates with two dierent types of media (nutrient rich LB and nutrient poor R2A). Source of biospeleothem Abbreviation R2A agar medium LB agar medium Chimant Tepui, Cueva Charles Brewer, Galera Adina CChB1 Various bacteria colonies, mould/fungi Various bacteria colonies Chimant Tepui, Cueva Charles Brewer, Cascada de Moravia CChB2 Various bacteria colonies, mould/fungi Various bacteria colonies, mould/fungi Chimant Tepui, Cueva Charles Brewer, Pared de los 100 Colores, inicial white microbial encrustations on the sandstone wall, at the end of the “Pared de los 100 colores”, on the right side of the corridor CChB3 No growth No growth Chimant Tepui, Cueva Charles Brewer, Pared de los 100 Colores, outermost part of the so white champignons CChB6 No growth No growth Chimant Tepui, Cueva Charles Brewer, Pared de los 100 Colores, on the ledge on the right side of corridor, black mud (red on the surface) covered by white, yellowish and copper-red lamentous and “lichen-like” aggregates, surface sample of aggregates-rich parts CChB9 Various bacteria colonies Various bacteria colonies Chimant Tepui, Cueva Juliana, 50 m from the cave entrance. White encrustations on the ceiling, partly hard (yellow parts), white so parts. White parts covered by lamentous and “lichen-like” aggregates (up to 5-6 mm) CJ1 Some bacteria colonies, mould/fungi Some bacteria colonies, mould/fungi Chimant Tepui, Cueva Colibr, colonnade behind the triple junction some 300 m from the entrance CK8 Some bacteria colonies, mould/fungi Some bacteria colonies, mould/fungi Chimant Tepui, Cueva Colibr, before waterfall on the triple junction, on the le side of the corridor CK9 Various bacteria colonies, mould/fungi Various bacteria colonies Roraima Tepui, Cueva de los Pmones, large corridor 100 m W from the cave entrance Pokemon 3 CLP1 Various bacteria colonies, mould/fungi Various bacteria colonies Roraima Tepui, Cueva de los Pmones, at the end of the large corridor with Venezuelan sign L6 CLP2 Various bacteria colonies, mould/fungi Various bacteria colonies Roraima Tepui, Cueva de los Pmones, the same place as CLP2 CLP3 Various bacteria colonies, mould/fungi Various bacteria colonies

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3. e important role of lateritization in speleogenesis is evident from vast quantities of the lateritic red mud (“Barro Rojo”) in these caves. is lateritization aects the arenites of Matau Formation which contain considerable amounts of feldspars, micas and clay minerals. In addition to creating cave spaces, lateritization is the main source of SiO 2 for the large opal spe leothems which occur in the caves. Lateritization here repre sents adissolution process that is volumetrically important and it may even be considered atrigger for speleogenesis. e arenitic caves in these Venezuelan tepuis can therefore be regarded as karst phenomena. 4. e following speleogenetic model can be inferred from the obtained results (Fig. 106): Stage 1 – the descending, SiO 2 bearing diagenetic solutions caused complete lithication of some beds, whereas other beds with more coarse-grained arenites were only penetrated by narrow channels through which uids owed to completely ll some of the lower beds. is resulted in contrasting diagenesis, where most beds turned to sandstone and quartzite while parts of other beds remained intact. Stage 2 – hard, isolated beds were broken, and the owing water which penetrated the poorly lithied beds signalled initial erosion. Lateritization then began in aluminosilicate-rich beds with the subsequent emptying of spaces by winnowing sand and other products of lateritization. e empty spaces were then supported solely by “nger-ow” pillars. Stage 3 – empty spaces collapsed further, thus creat ing larger caves, and superior propagation of these collapses created large collapse depressions on the surface. 5. Flexible sandstone – itacolumite which was found in both examined cave systems possesses unique exibility due to very thin spaces between the arenitic grains. Although the origin of these spaces requires clarication, quartz dissolution was observed in the itacolumite samples, and this is dissimilar to occurrences in other arenitic specimens. 6. A new theory concerning the origin of tepuis is presented in this volume. According to this theory, tepuis originated in places where there was an intensive descending uid ow, most likely emanating from surface water reservoirs, such as rivers or lakes. is continuous ow carried SiO 2 from the lateritized surface beds. us, the underlying part of the Roraima Super group was impregnated with SiO 2 and strongly lithied. ese indurated parts of the formation remained as tepuis, while the remainder of the formation was removed by erosion. e soness of the underlying, non-lithied sediment below the tepuis causes undercuing of their margins thus maintaining steep walls. Speleogenesis in the tepuis was a process which most likely began at a later stage, with initial incision of the valleys followed by erosion. e recent “Barro Rojo” represents a new lateritic product, and it has nothing in common with the ancient silicication of the Matau Formation. 7. e vast majority of speleothems in the examined cave systems are siliceous, ranging from opal-A to micro-crystalline quartz. Speleothems from gypsum and sanjuanite were documented in some other places, and the laterite “Barro Rojo” is a further form of speleothem. Some of the siliceous speleothems have inorganic origin; they precipitated from water solutions by evaporation. ese mainly include owstones and stalactites, with the laer occasionally formed by encrustation of spider threads hanging from ceilings, thus forming the unique spe leothems called “teleraas”. However, the vast majority of siliceous speleothems are microbialites, where initial microbial mats are encrusted by silica, leaving the surrounding rock intact. is procedure indicates that these microbes actively mediate silica precipitation and they are not just passive com ponents of the speleothems. Although these microbial spe leothems have many shapes and forms, their anatomy reveals they contain the following two main forms of microbialites; (1) columnar stromatolites, consisting of erect lamentous microbes; and (2) peloidal stromatolites, where the peloids are composed of short-lamentous microbes. Although the Tab. 7: Table showing preliminary results from ongoing nucleic acid extraction attempts from six dierent biospeleothems. Source of biospeleothem Abbreviation DNA-concentration (g/l) Chimant Tepui, Cueva Charles Brewer, Galera Adina CChB1 116.22 Chimant Tepui, Cueva Charles Brewer, Cascada de Moravia CChB2 0.31 Chimant Tepui, Cueva Charles Brewer, Pared de los 100 Colores CChB6 1.63 Chimant Tepui, Cueva Colibr, colonnade behind the triple junction some 300 m from the entrance CK8 72.18 Roraima Tepui, Cueva de los Pmones, large corridor 100 m W from the cave entrance Pokemon 3 CLP1 123.18 Roraima Tepui, Cueva de los Pmones, at the end of the large corridor with Venezuelan sign L6 CLP2 16.36 –

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nature of these microbes is not yet fully understood, work on unravelling their mysteries still continues. Biological identication based on enrichment, molecular microscopy using uorescence in situ hybridization and DNA analysis is currently underway. While this work is still in progress, only morphological criteria are available for their current identication, and these may not prove completely reliable. e morphology of both these microbe types bears some resemblance to cyanobacteria. For example, microbes similar to the Oscillatoriales order of cyanobacteria resemble co lumnal stromatolitic forms. In addition, other lamentous microbes, including the Beggiatoa sulphur bacteria and the Gallionella iron oxidizing bacteria cannot yet be excluded. It appears likely that dierent types of lamentous bacteria are associated with dierent types of biospeleothems, and this depends on the surrounding geochemical conditions. For example, Gallionella -like laments are ubiquitous in “Barro Rojo”. e peloidal microbialites are formed by lamentous microbes reminiscent of Nostoc -type cyanobacteria but even tual symbiosis with fungi species is not excluded. . rf f – nfnr, n f Fig. 106: Schematic overview of the speleogen esis in the arenites of the Roraima Supergroup. Grey – well-lithied arenites, pale – poorly lithied arenites (cavities formed by lateritiza tion are omitted). A-B – The gradual diagenesis of arenites caused by descending silica-bearing uids (Stage 1). C – Two poorly-lithied horizons superimposed on each other. D-E – Flowing water penetrated the vertical cleft (on the right side) causing gradual winnowing of the poorly lithied sediment (Stage 2). F – Two horizons re mained empty (two superimposed initial caves), with lithied pillars oering the only support against collapse. G-H – Gradual collapse of both oors, forming a large cave (Stage 3).

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“Islands in time” it is a term introduced by Brewer-Caras (1974) to describe the isolation of the plants and animals inhabiting the remote summits of those peculiar mountains with a table shape in the Venezuelan Guyana. ese mountains are known as tepuis (tepui in singular), a derived term of the indigenous language Pemn (tep), which in fact means “mountain”. e unusual shape of most of them, with their vertical clis that make them virtually inaccessible, their apparently plain sum mits from the distance, and their isolation of the rest of tropical lowlands, took the novelist sir Arthur Conan Doyle to represent his acclaimed novel “e Lost World” in the scenario oered by one of the most famous tepuis, Roraima. e ecological community of the tepuis summits is considered a distinct and discontinuous biogeographical province called Pantepui (Mayr & Phelps, 1967). e Pantepui includes about 50 mountains (topographic islands) with elevations ranging from 1,500 to 3,000 m a.s.l. ey cover an area of about 5,000 km 2 and their surface area ranges between 0.2 and 1,096 km 2 (Berry et al., 1995; McDiarmid & Donnelly, 2005). e region is known for its extraordinary diversity and high level of end emism, which is, above all, remarkable at the isolated summits of the sandstone mesas (Huber, 2005; Rull, 2005; McDiarmid & Donnelly, 2005). In this chapter we tried to summarize the results of faunistical investigations of three dierent animal groups: land snails, aquatic insects, and amphibians and reptiles in the Pantepui. 3.1. THE PANTEPUI MALACOFAUNA: LAND SNAILS OF CHUR TEPUI AND OTHER TEPUIS IN SOUTHERN VENEZUELA AND ADJACENT AREAS 3.1.1. Introduction Land snails (Mollusca, Gastropoda) have been proposed as good model organisms for the study of complex ecosystems. ey are renowned for their limited dispersal abilities, they can be easily collected and most of them can be identied on the basis of their shells. Land snails are also an important factor in the food web and are vulnerable to predation by other animals or their shell is used as a calcium source. However, tropical acidic soils are known to support only sparse land snail populations (Schilthuizen, 2011). Although the Neotropical land snail fauna is generally well-known, the Pantepui area (sensu Huber, 1995) is less-studied; this is the assemblage of sandstone table moun tains in Venezuelan Guyana and in adjacent Brazil and Guyana. According to Huber (1995), the term Pantepui denes the area above 1,500 m elevation, but some authors include all the in tervening lowlands as well. In this chapter we use Pantepui as comprising both the highlands and uplands (sensu Huber, 1988), but we treat all the land snail species reported from southern Venezuela and adjacent areas in Brazil. Currently, there is a to tal of 21 identied species (Tab. 8), 19 of which are endemic to the area. In addition, it is noteworthy that the identity of some reported species remains obscure at this time. is particularly refers to a juvenile Plekocheilus species (family Amphibulimidae) from near Santa Elena de Uairn (Breure, 2009), and a Hap piella species (family Systrophiidae) from Macizo del Chimant (Haas, 1955). ese species have been reported both from the highlands ( Happiella ) and lower elevations ( Plekocheilus ), and are a token of the relatively unexplored malacofauna of this region. Incidentally, both were collected by botanists (O. Huber, J.A. Steyermark respectively), and this illustrates a more generalized paern: there is generally a paucity of data, with all known snails being collected by non-malacologists, such as botanists and herpetologists. e expeditions to Cerro de la Neblina (BrewerCaras, 1988) and Chur Tepui (Brewer-Caras & Audy, 2010), however, are exceptions with also special interest for malacol ogy. e aim of this chapter is to review all known species from this area, to provide additional anatomical and distributional data for Orthalicoidea, and to present preliminary cladistic and phylogenetic analyses for Plekocheilus species. – 3. Faunistic investigations of the Pantepui biogeographical region

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– Tab. 8: Taxonomy of land snails reported from southern Venezuela and from adjacent areas in Brazil, arranged according to tepui massifs. Abbreviations: CH, Chimant; DU, Duida-Marahuaka; GU, Guaiquinima; MA, Maigualida; NE, Neblina; RO, Roraima; YA, Yapacan. Altitudinal distibution following Huber (1988): *, lowland; **, upland; ***, highland. References: [1] Breure, 2009; [2] Breure & Schlgl, 2010; [3] Borrero & Breure (2011); [4] Simone, 2010; [5] Thompson, 2008. Notes: 1 The assign ment of the genus Plekocheilus to the family Amphibulimidae now follows Breure et al., 2010. 2 Plekocheilus (Eurytus) coloratus (Nyst, 1845), reported by Breure (2009: 39), is a dierent but as yet unidentied species. 3 A single worn shell was tentatively identied as this species, hitherto only known from Colombia. Clade Stylommatophora Superfamily Clausilioidea Gray, 1855 Family Clausiliidae Gray, 1855 Genus Columbinia Polinski, 1924 Columbinia (C.) exul ompson, 2008; NE; ***; [5] Superfamily Orthalicoidea Albers, 1860 Family Amphibulimidae P. Fischer, 1873 1 Genus Plekocheilus Guilding, 1828 Plekocheilus (P.) linterae (Sowerby, 1890); RO; ***; [1] Plekocheilus (P.) alticola Haas, 1955; CH; ***; [1] Plekocheilus (P.) vlceki Breure & Schlgl, 2010; CH; ***; [2] 2 Subgenus Eurytus Albers, 1850 3 Plekocheilus (Eurytus) plectostylus (Pfeier, 1848); MA; ***; [3] Plekocheilus (Eurytus) gibber (Oberwimmer, 1931); DU; ***; [1] Plekocheilus (Eurytus) fusitorsus (Oberwimmer, 1931); DU?, GU; ***, ?**, ??*; [1] Plekocheilus (Eurytus) juliani Haas, 1955; CH; ***; [1] Plekocheilus (Eurytus) mundiperditi Haas, 1955; CH; ***; [1] Plekocheilus (Eurytus) tatei Haas, 1955; DU; ***; [1] Plekocheilus (Eurytus) sophiae Breure, 2009; RO; ***; [1] Plekocheilus (Eurytus) tepuiensis Breure, 2009; YA; **; [1] Plekocheilus (Eurytus) huberi Breure, 2009; NE; ***; [1] Plekocheilus (Eurytus) nebulosus Breure, 2009; NE; ***; [1] Plekocheilus (Eurytus) breweri Breure & Schlgl, 2010; CH; ***; [2] Subgenus Eudolichotis Pilsbry, 1896 Plekocheilus (Eudolichotis) sinuatus (Albers, 1854); *; [1] Family Bulimulidae Tryon, 1867 Genus Drymaeus Albers, 1850 Drymaeus (D.) steyermarki (Haas, 1955); CH; ***; [1] Drymaeus (D.) extraneus (Haas, 1955); CH; **, ***; [1] Drymaeus (D.) yapacanensis Breure & Eskens, 1981; YA; **; [1] Drymaeus (D.) rex Breure, 2009; NE; *, **, ***; [1] Superfamily Helicoidea Ranesque, 1815 Genus Olympus Simone, 2010 Olympus nimbus Simone, 2010; NE; *; [4] Tab. 9: Key to families and genera of the Pantepui gastropods. 1 Shell sinistral ... Clausiliidae, Columbinia exul – Shell dextral ... 2 2 (1) Shell depressed, height/diameter ratio < 1.0 ... Pleurodontidae, Olympus nimbus – Shell elongate, height/diameter ratio > 1.0 ... 3 3 (2) Protoconch granulate ... Amphibulimidae, Plekocheilus Protoconch with a grating sculpture of equally strong spiral riblets and axial striae ... Bulimulidae, Drymaeus Tab. 10: Key to Plekocheilus species which occur in the uplands and highlands of Venezuelan Guyana. 1 Sculpture on last whorl malleated ... 2 – Sculpture on last whorl consisting of ne granules, spirally arranged “puckered” bands, or horizontal threads which are partly anastomosing ... 4 2 (1) Malleation weakly developed over a sculpture of axial riblets broken by spiral lines into oblong granules; shell spindle-shaped; Roraima ... P. linterae – Malleation strongly developed; Macizo del Chimant ... 3 3 (2) Shell up to 31 mm, uniform (dark-)yellowish to chestnut-brown colour; Chur Tepui ... P. vlceki – Shell up to 44 mm, coloured with reddish-brown zig-zag streaks; Toron Tepui ... P. alticola 4 (1) Sculpture consisting of horizontal treads, partly anastomosing ... 5 – Sculpture consisting of ne granules, or spirally arranged “puckered” bands ... 6 5 (4) Shell up to 44 mm, colour uniform reddish-brown, suture descending in front; Yuruan Tepui ... P. sophiae – Shell up to 62.5 mm, colour (dark-)brownish with irregularly spaced darker coloured spots, suture slightly ascending in front; Neblina ... P. nebulosus 6 (4) Sculpture consisting of granules ... 9 – Sculpture consisting of spirally arranged “puckered” bands ... 7 7 (6) Shell up to 52 mm, colour yellowishto (light) chestnut-brown, with descending oblique, partly zig-zag stripes of reddishto blackish-brown ... 8 – Shell up to 47 mm, colour (dark) brown with darker brown to blackish dots dispersed; northern part of Macizo del Chimant ... P. mundiperditi 8 (7) Shell up to 42 mm, last whorl relatively swollen, suture regularly descending in front; Chur Tepui ... P. breweri – Shell height 46-52 mm, last whorl relatively at, suture deeply descending in front; Macizo del Chimant ... P. juliani 8 (6) Shell larger than 40 mm ... 9 – Shell smaller than 40 mm; Yapacan-tepui ... P. tepuiensis 9 (8) Shell larger than 48 mm, colour with irregular dots or with descending, brown streaks ... 10 – Shell up to 48 mm, colour light chestnut brown with a regular paern of descending, oblique, narrow reddish-brown stripes; Neblina ... P. huberi 10 Colour paern with dispersed dots, forming a few short, irregular streaks; aperture narrow and oblique; Cerro Marahuaka ... P. gibber Colour paern with descending, brown streaks ... 11 11 (10) Colour paern with dark-brown to blackish streaks, parallelled with yellow ones, suture slightly ascending in front; Ro Padamo; Guaiquinima ... P. fusitorsus – Colour paern with dark-brown streaks only, suture not ascending nor desending in front ... P. tatei

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3.1.2. Material and methods e following abbreviations are used to refer to depositories of ma terial: AMNH, American Museum of Natural History, New York, U.S.A.; INPA, Instituto Nacional de Pesquisas da Amaznia, Manaus, Brazil; MLSC, Museo de Historia Natural ‘La Salle’, Caracas, Venezuela; MZSP, Museu de Zoologia, Universidade de So Paulo, Sao Paulo, Brazil; NHM, Natural History Museum, London, U.K.; RMNH, Naturalis Biodiversity Centre (formerly Rijksmuseum van Natuurlijke Historie), Leiden, the Netherlands; SNMSZ, Slovak National Museum, Bratislava, Slovakia; UF, Florida State Museum of Natural History, Gainesville, U.S.A. Mandibulae and radulae were studied under a Cambridge-II ( Plekocheilus mundiperditi and Drymaeus steyermarki ) and JEOL JSM-6480LV Scanning Electron Microscope (all other species). Morphological analyses were performed with a cladistic parsi mony analysis using a ‘traditional search’ in the program TNT (Golobo et al., 2008). e ve characters used were coded as multistate and treated as unordered (Tab. 12). Preliminary phy logenetic molecular analyses were performed using Plekocheilus taxa, from both the Pantepui area and the Andean and West Indies regions. ese analyses were carried out using partial cytochrome c oxidase subunit 1 (CO1) sequences. DNA was extracted from the foot of the snails with a DNEasy kit (Qiagen, Inc.) following the manufacturer’s protocol for animal tissues; gene fragments were amplied in 25 l reactions. Fragments of mitochondrial cytochrome oxidase 1 (CO1) were amplied using primers HCO2198 and LCO1490 (Folmer et al., 1994). Most reactions consisted of 2.5 l of Qiagen PCR buer, 0.5 l of 10 mM dNTP, 1 l each of forward and reverse 10 mM prim ers, 0.25 l Taq DNA Polymerase (Qiagen Inc.), 1 l of template DNA, and water to 25 l. Reaction conditions included an initial t. b n b nn n Tab. 12: Plekocheilus species arranged according to shell morphology: shell shape (0 = sides slightly convex/aperture relatively small, 1 = sides straight/ aperture relatively large, 2 = sides hardly convex/aperture relatively wide); suture (0 = normal or slightly ascending in front, 1 = descending in front); colu mella (0 = no columellar fold, 1 = weak fold, 2 = strong fold); colour pattern (0 = dots, 1 = axial zig-zag streaks, 2 = obliquely descending streaks); sculpture (0 = malleation, 1 = granulation, 2 = ‘puckered’ bands, 3 = horizontal threads). Shell shape Suture Columella Colour Sculpture alticola 0 0 2 2 0 breweri 2 1 1 1 2 fusitorsus 2 0 1 1 1 gibber 1 0 2 2 1 huberi 1 0 0 2 1 juliani 1 1 0 2 1 linterae 0 1 2 2 0 mundiperditi 2 1 1 0 2 nebulosus 2 1 1 0 3 sophiae 2 1 0 0 3 tatei 2 0 1 2 1 tepuiensis 2 0 1 2 1 vlceki 0 0 1 2 0 Tab. 11: Key to the species of Drymaeus of Venezuelan Guyana. 1 Shell relatively large (up to 40.7 mm) with prominent last whorl, colour paern varied; Neblina ... D. rex Shell relatively smaller (up to 32 mm) ... 2 2 (1) Peristome well expanded, colour paern with axial bands, which may be partly forked above; Yapacan Tepui ... D. yapacanensis – Peristome narrowly expanded, colour paern uniform or with spiral bands ... 3 3 (2) Shell with straight sides, aperture relatively large; Apacar Tepui ... D. steyermarki – Shell with slightly convex sides, last whorl somewhat swollen, aperture relatively smaller; Abacap Tepui, Apacar Tepui ... D. extraneus

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– Fig. 107: Shells from the Pantepui area. A – Plekocheilus alticola Haas, 1955. B – P. linterae (Sowerby, 1890). C – P. vlceki Breure & Schlgl, 2010. D – Drymaeus extraneus (Haas, 1955). E – D. steyermarki (Haas, 1955). F – P. sophiae Breure, 2009. G – P. breweri Breure & Schlgl, 2010. H – P. mundiperditi Haas, 1955. I – P. juliani Haas, 1955. J – P. fusitorsus (Oberwimmer, 1931). K – P. gibber (Oberwimmer, 1931). L – P. tepuiensis Breure, 2009. M – P. nebulosus Breure, 2009. N – P. huberi Breure, 2009. O – P. tatei Haas, 1955. P – D. yapacanensis Breure & Eskens, 1981. Q – Olympus nimbus Simone, 2010. R – Columbinia exul Thompson, 2008. S – D. rex Breure, 2009. The scale line equals 2 cm (Q), 1.25 cm (R), 1 cm (all other gures).

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denaturation step at 94 C for 3 min, followed by 40-45 cycles of 94 C for 15 s and annealing at 50 C (COI) for 30 s and 72 C for 40 s. PCR products were puried, and then sequenced under BigDye terminator cycling conditions, puried by ethanol pre cipitation and run on an Applied Biosystems 3730xl sequencer by Macrogen. All sequences were checked for contamination using a Blast search. Phylogenetic molecular analyses were per formed using PhyML in Geneious 5.3.4 (Drummond et al., 2010; Guindon & Gascuel, 2003), using 500 bootstrap replicates, the Chi2-based aLRT parametric (Anisimova & Guscuel 2006) and an aLRT non-parametric branch support based on a ShimodairaHasegawa-like procedure (see benchmarks on hp://www. Molecular analyses were achieved with the most appropriate model of sequence evolution (GTR+Gamma+Inv) selected by jModeltest 0.1.1 (Posada, 2008), and phylogenetic network analysis was completed using SplitsTree 4.11.3 (Huson & Bryant, 2006), with a NeighborNet drawn using K2P distance method, followed by a bootstrap of 1000 replicates. e closely related (Breure et al., 2010) taxa Gaeotis nigrolineata , G. avolineata and Pellicula appendiculata were utilized as the outgroup. 3.1.3. Land snails in a hostile habitat Snails use sources of calcium for the formation of their shells during growth. In the Pantepui area, limestone is not available due to the sandstone substrate; the only calcium sources appear to be the uptake of calcium from plants (Van Bruggen, pers. commun.) and the leaching of mineral from the sandstone rocks. Although no studies have been carried out on shell formation in these habitats, it can be safely assumed that both the geology of the area and the acidity of the habitat oer a challenge for land snails during their growth. is may partly explain their low abundance. As far as current data allows a conclusion, the occurrence of snails is concentrated on or near the summits of the tepuis. Huber (1988) has made a distinction between high lands (> 1,500 m), uplands (500–1,500 m) and lowlands (< 500 m). From the 21 species reported in this area, 14 are known to inhabit only the highlands; two are only from the uplands and one species has a broad altitudinal distribution (Tab. 8). Ecologically, with the exception of Olympus nimbus , which is ground-dwelling, all species have been observed in low shrubs or tree-like vegetation (notably Brocchinia and Bonnetia forests with trees up to 3 m high). In a Principal Component Analysis (PCA) of dierent factors related to snail distribution, it appears that endemic plant species play an important role in the primary PCA factor of habitat diversity (Breure, 2009: tab. 5). Local endemic plant species have mainly been recorded from the slopes and summits of individual tepuis, with the highest numbers recorded at Cerro de la Neblina, Macizo del Chimant, Cerro Duida and Cerro Sipapo (Berry et al., 1995; Huber, 1988). Among these plant endemics, Bonnetia species are worth mentioning since several endemic snails appear to be associated with them. It is noteworthy that Plekocheilus species in the Pantepui area oen occur in paramoid scrub (Breure, 2009; Huber, 1988; Huber, 1995: pl. 37), a habitat which they share with certain Andean species groups in the same genus. 3.1.4. Systematics All known land snails from the Pantepui region are Stylom matophora, with the majority classied in the superfamily Orthalicoidea. For a key to families, genera, and species, see Tables 9-11. e species are summarized below; see ompson (2008), Breure (2009), Simone (2010), and Breure & Schlgl (2010) for more details, especially on the anatomy (data on radu lae and mandibulae is presented below for Orthalicoid species). e species are treated according to the dierent regions in the Pantepui area relevant to this paper; Berry et al. (1995) distin guished Eastern (herein Roraima, Yuruan, and Macizo del Chimant), Central, Western, and Southern Pantepui regions. Species of Macizo del Chimant Seven identied land snail species occur on the various tepuis which form part of Macizo del Chimant. ese are; Plekocheilus (P.) alticola Haas, 1955 (Fig. 107A) Description: e shell is up to 44.3 mm, 1.75 times longer than wide, elongate-ovate, last whorl relatively slender, darkbrown coloured with oblique reddish-brown stripes, sculptured with malleation and a distinct columellar fold visible in the aperture. Distribution. e sole locality known is Toron Tepui, where this type material was collected on the slopes bordering Cao Mojado, 2,250 m. Type material in FMNH (52442, holotype). Remarks. Breure & Schlgl (2010) expressed doubts on the subspecic status of Plekocheilus fulminans alticola and P. f. lin terae (Sowerby, 1890). Diagnosis: Aer having studied the type of P. fulminans (Nyst, 1845) in the Brussels collection (Breure, 2011), these two taxa are treated herein as separate species. Plekocheilus (P.) vlceki Breure & Schlgl, 2010 (Figs. 107C, 108L–M) Description: e shell is up to 30.9 mm, 1.75 times longer than wide, with an almost uniform (dark-) yellowish to chestnutbrown colour, a nely malleated sculpture crossed by spiral lines on the last whorl and a marked columellar fold. Its colour is yellowish-beige. Radula. Rows are slightly V-shaped, the outermost lateromaginals curved distally; radula formula C/1 + LM 60/2 (teeth type C-6, LM-10, LM-11; see Breure, 1978, 1979). e central teeth are monocuspid, triangular, rst lateral teeth acute, with weakly developed ectocones, the next 16 lateromarginals bi cuspid, with rather blunt spatula-shaped mesocones and more acute, ovate ectocones. e outer 44 lateromarginals bicuspid, shied, with rather blunt spatula-shaped mesocones and blunt deltoid ectocones, which may be bid in the outermost teeth. Genitalia. See Breure & Schlgl (2010: g. 4A). Ecology. Found on the oor of a canyon covered with a dense Bonnetia forest and low vegetation. e snails occurred in Broc chinia tatei (Bromeliaceae) at the time of collecting. Distribution. Known only from Chur Tepui, Sima Colibr, 2,100 m. Type material in MZSP, RMNH (114233, holotype), and UF. t. b n b nn n

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Remarks. e central teeth of the radula are without the slight protuberances at base reported for P. (Eurytus) species and the rst lateral teeth are more acute than the second and beyond. is paern has also been observed in P. (P.) aurissileni (Born, 1780), type species of the genus, and a number of other Plekocheilus species (Breure, 1978). e mesocones of the rst lateral in P. vlceki are, however, more developed than those in the group just mentioned, and resemble those of P. (Eurytus) species from Pantepui. Plekocheilus (Eurytus) juliani Haas, 1955 (Fig. 107I) Description: e shell is up to 54.2 mm, twice as long as wide, elongate-ovate, colour paern consisting of obliquely descending dark-brown to blackish stripes on a brown background which is darker on the last whorl. Sculpture consisting of short, oblong granules arranged in spiral rows. Ecology. Steyermark collected the species in Bonnetia forest. Distribution. It occurs on Macizo del Chimant: summit of Apacar Tepui, 2,100 m; northwest part of summit of Abcapa Tepui; Auyn Tepui, 1,970 m. Specimens tentatively referred to this species have been found on Chur Tepui, 2,130 m. Type material in FMNH (49737, holotype). Plekocheilus (Eurytus) mundiperditi Haas, 1955 (Figs. 107H, 108F–I, 108O) Description: e shell is up to 55.3 mm, 1.8 times longer than wide, elongate-ovate, last whorl somewhat swollen and saccate, colour paern with blackish to dark-brown dots on a (dark-) brown background. Sculptured with puckered spiral bands of oblong granules divided by narrow, smooth areas. Mandibula. Bow-shaped, central part consisting of three fused plates with 14 lateral plates on each side, tapering towards the end. Radula. Data additional to Breure (1978). Rows straight; radula formula, one monocuspid central tooth (C/1) and 59 bicuspid lateromarginals (formula: C/1 + LM 59/2; teeth types C-6, LM-10, LM-11, see Breure 1978). e central teeth are monocuspid, with triangular to ovate mesocones and weakly developed protuberances. e rst 15 lateromarginals bicuspid, with rather blunt spatula-shaped mesocones and more acute, ovate ectocones. e outer 44 lateromarginals bicuspid, shied, with rather blunt spatula-shaped mesocones and blunt deltoid ectocones, which may be bid in the outermost teeth. Ecology. Found in herbaceous vegetation and in Bonnetia forest. Distribution. Widely distributed on Macizo del Chimant: Apacar Tepui, 2,150 m; Aparamn Tepui, 2,120 m; Toron Tepui, bordering valley of Cao Mojado, 2,250 m; Murey Tepui, 2,300 m. Type material in FMNH (52436, holotype). Plekocheilus (Eurytus) breweri Breure & Schlgl, 2010 (Figs. 107G, 108R) Description: e shell is up to 41.7 mm, 1.8 times longer than wide, colour paern with oblique stripes of reddish – to blackishbrown, oen with a yellowish ‘shadow’ besides the stripes on the last whorl. Sculptured with spiral, puckered bands of oblong granules. Its colour is dark-grey to blackish. Mandibula. Bow-shaped, central part consisting of three fused plates, 12 lateral plates on each side, tapering towards the end. Radula. Row straight; radula formula C/1 + LM 52/2 (C-6, 20 lateromarginals C-10, 32 lateromarginals C-11); similar to P. mundiperditi . Genitalia. See Breure & Schlgl (2010: g. 4B–F). Ecology. Collected in stands of Brocchinia hechtioides , up to 1 m high, and in Brocchinia tatei . See Breure & Schlgl (2010) for more details and discussion of the relationship between snails and carnivorous plants in the area. Distribution. Chur Tepui; both on the summit plateau (2,400 m) and in the canyon Sima Colibr (2,285 m). Type material in MLSC, MZSP, RMNH (114235, holotype), SNMSZ and UF. Drymaeus (D.) steyermarki (Haas, 1955) (Figs. 107E, 108A–E) Description: e shell is 27.3 mm, 2.1 times longer than wide, colour whitish to brownish with irregular axial, small streaks of chestnut-brown. White lip, with a very faint pinkish border lining the inside of the aperture. Radula. Data additional to Breure & Eskens (1981). Rows slightly curved; radula formula C/1 + LM 53/3 (C-8, LM-12). Central teeth monocuspid, with relatively small, acute triangu lar mesocones. e lateromarginals are tricuspid, shied, with rather blunt ovate mesocones, acute elongate-ovate endocones and acute, deltoid ectocones, which may be bid in the outer most teeth. Distribution. A single known specimen, collected on plateau below the summit of Apacar Tepui, 1,800 m. Type material in FMNH (49735, holotype). Drymaeus (D.) extraneus (Haas, 1955) (Fig. 107D) Description: e shell is up to 32 mm, 2.2 times longer than wide, uniform whitish or with spiral colour bands of reddishbrown, side slightly convex. Mandibula. See Breure & Eskens (1981: g. 340). Radula. Formula C/3 + LM 90/3 (C-12, LM-18). See Breure & Eskens (1981: tab. 4). Distribution. Summit of Apacar Tepui, 2,100 m, and along the trail from Ro Tirica to the lower summit camp, 1,800 m; west side of Abacap Tepui, 1,189 m. One adult and two juvenile specimens known. Type material in FMNH (49736, holotype). Species from other tepui areas Eastern Pantepui region Eastern Pantepui region has only partly been explored in terms of its malacofauna. Only two tepuis, Roraima Tepui and Yuru an Tepui are currently known to have (endemic) snail species. Plekocheilus (P.) linterae (Sowerby, 1890) (Fig. 107B) Description: e shell is up to 43 mm, 1.8 times longer than wide, elongate-ovate, with a relatively slender last whorl, some irregular, undulating axial reddish-brown stripes may be present, sculptured with axial riblets broken into oblong granules by spiral, incised lines on the last whorl. Distribution. Known from Roraima Tepui, 2,400 m. Type material in NHM (1889.4.25.1, holotype). –

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t. b n b nn n Fig. 108: Scanning electron microscope photographs. Radulae. A–E – Drymaeus steyermarki (Haas, 1955); A – overview of radula, x120; B – central teeth, x2300; C – lateromarginal 2, x1150; D – lateromarginals 12–14, x570; E – lateromarginals 43–49, x570. F–I – Plekocheilus mundiperditi Haas, 1955; F – central teeth, x1200; G – lateromarginal 2, x1250; H – lateromarginals 9–16, x240; I – lateromarginal 22, x1200. J–K – P. nebulosus Breure, 2009; J – central and lateromarginals 1–9; K – lateromarginals 104. L–M – P. vlceki Breure & Schlgl, 2010; L – central and lateromarginals 1–9; M – lateromarginals 11–45. Mandibulae. N – P. nebulosus Breure, 2009. O – P. mundiperditi Haas, 1955. P – P. huberi Breure, 2009. Q – P. tatei Haas, 1955. R – P. breweri Breure & Schlgl, 2010.

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Plekocheilus (Eurytus) sophiae Breure, 2009 (Fig. 107F) Description. e shell is 44 mm, 1.9 times longer than wide, elongate-ovate, last whorl rather convex, surface shining, sculp tured with horizontal treads, partly anastomosing. Its colour is light brownish, with grey tentacles. Genitalia. See Breure (1978: g. 2 [as P. blainvilleanus linterae ]). Distribution. Described from a single shell in the UF collec tion (holotype 24413). In December 2010, a living specimen was observed at the type locality, Yuruan Tepui, 2,300 m (Ph. Kok, pers. commun.). Central Pantepui region In this region, snail species have been recorded only from Cerro Guaiquinima, Cerro Marahuaka and Cerro Duida. Plekocheilus (Eurytus) fusitorsus (Oberwimmer, 1931) (Fig. 107J) Description: e shell is up to 63.3 mm, 1.7 times longer than wide, colour (yellowish-)brown with darker, undulating stripes which are bordered by a yellowish ‘shadow’ on the last whorl, sculptured with ne granulation, aperture ovate, relatively wide. Distribution. “Ro Padamo” (type locality); Cerro Guaiquini ma. Type material in SMF (5142, holotype). Plekocheilus (Eurytus) gibber (Oberwimmer, 1931) (Fig. 107K) Description: e shell is 55.3 mm, twice as long as wide, colour yellowish, turning reddish-brown on the upper whorls, with irregular dots and short, narrow undulating lines of the same colour on the last whorl, sculptured with ne granulation, ap erture ear-shaped with a distinct columellar fold. Distribution. Known only from the holotype, collected on Cerro Marahuaka, 2,170 m (SMF 5143). Plekocheilus (Eurytus) tatei Haas, 1955 (Figs. 107O, 108Q) Description: e shell is up to 62 mm, 1.9 times longer than wide, colour brownish, lighter on the upper whorls, the last whorl with dark brown, oblique, slightly zig-zag stripes, sculptured with very ne granulation. Aperture ovate, relatively wide, with a weak columellar fold. Its colour is dark-brown. Mandibula. Bow-shaped, central part consisting of three fused plates, eight lateral plates on each side, tapering towards the end. Radula. Rows slightly V-shaped; radula formula C/1 + LM 42/2 (C-6, 14 lateromarginals C-10, 28 lateromarginals C-11); similar to P. mundiperditi . Genitalia. See Breure (2009: g. 2A). Distribution. Cerro Duida. Type material in AMNH (73455, holotype) and FMNH. Plekocheilus (Eurytus) tepuiensis Breure, 2009 (Fig. 107L) Desription: e shell is 35 mm, 1.7 times longer than wide, pale yellowish-brown with obliquely descending zig-zag streaks; surface hardly shining, with spiral lines of dot-like granules on the last whorl. Distribution. Known only from the holotype in RMNH (112031), collected at 800 m elevation on Yapacan Tepui. Drymaeus (D.) yapacanensis Breure & Eskens, 1981 (Fig. 107P) Description: e shell is up to 31.2 mm, 2.2 times longer than wide, colour pink to yellowish, with axial reddish-brown streaks, which may be forked above but are broader below. Aperture with a slightly expanded peristome, pink inside. Mandibula. See Breure & Eskens (1981: g. 343). Radula. See Breure & Eskens (1981: pl. 3, gs 5–6). Genitalia. See Breure & Eskens (1981: g. 159). Distribution. Endemic to Yapacan Tepui; recorded from 1,300 m elevation. Type material in RMNH (55331, holotype). Plekocheilus (Eudolichotis) sinuatus (Albers, 1854) Remarks: A single shell was found in the lowland northwest of Yapacan Tepui (Breure, 2009: p. 39, g. 6K). Western Pantepui region is region is virtually unknown for malacofauna. Plekocheilus (Eurytus) cf. plectostylus (Pfeier, 1848) Remarks: One weathered specimen, tentatively referred to this species is reported by Borrero & Breure (2011) from Cerro Guanay at the eastern tributary of Ro Parguaza. is is ap proximately 05 51’ N 066 18’ W. e shell was found in tepui scrub at about 1,700 m, in the central-southern summit section of the meseta (O. Huber, pers. commun.). Southern Pantepui region Snails have only been collected on the Cerro de la Neblina, which is partly in Venezuela and partly on Brazilian territory. Columbinia exul ompson, 2008 (Fig. 107R) Description: e shell is slender, up to 24 mm, 4.5 times longer than wide, colour brownish, lighter at the blunt apex which is minutely granulate, teleoconch sculptured with ne, straight thread-like riblets, last whorl relatively short. Aperture ovate, approximately as wide as shell, projecting forward on a short neck, the palatal plica are at a relatively low position. Anatomy. See ompson (2008). Ecology. Collected in a dense, broadleaf rainforest 4–5 m above ground level on a dead tree-trunk. Distribution. Venezuela, Edo. Amazonas, Cerro de la Neblina, valley north of Pico Phelps, at 1,200–1,400 m elevation. Type material in MLSC, SMF and UF (48631, holotype). Plekocheilus (Eurytus) huberi Breure, 2009 (Fig. 107N) Description:. e shell is up to 47.9 mm, twice as long as wide, thin, with light chestnut-brown colouring and descending, nar row reddish-brown ‘lightning’ stripes; an almost lustreless sur face, very nely granulated on the last whorl. Mandibula. Bow-shaped, central part consisting of three fused plates, ten lateral plates on each side, tapering towards the end. Radula. Rows slightly V-shaped; radula formula C/1 + LM 44/2 (C-6, 17 lateromarginals C-10, 27 lateromarginals C-11); similar to P. mundiperditi . Genitalia. See Breure (2009: g. 2B–D). Ecology. Found in a cloud forest in bromeliads. Distribution. Venezuela, Edo. Amazonas, Cerro de la Neblina, at the Brazilian-Venezuelan border and near Pico Maguire; at 1,800–2,000 m elevation. Type material in RMNH and UF (284764, holotype). –

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Plekocheilus (Eurytus) nebulosus Breure, 2009 (Figs. 107M, 108J–K) Description; e shell is up to 62.5 mm, twice as long as wide, sculptured on the last whorl with horizontal threads of vari ous length, oen anastomosing; with darker spots on uniform brownish background colouring; aperture decidedly descending in front, peristome somewhat thickened and reexed. Mandibula. Bow-shaped, central part consisting of three fused plates, nine lateral plates on each side, tapering towards the end. Radula. Rows slightly V-shaped; radula formula C/1 + LM 42/2 (C-6, 16 lateromarginals C-10, 26 lateromarginals C-11); similar to P. mundiperditi . Genitalia. See Breure (2009: g. 2E–F). Ecology. Found in bromeliad scrub forest of Bonnetia magu iereorum , 2–3 m high. Distribution. Venezuela, Edo. Amazonas, Cerro de la Neblina, various localities near Pico Phelps and Pico Maguire; at 1,800– 2,100 m elevation. Type material in RMNH and UF (284723, holotype). New records: Brazil, Edo. Amazonas, Pico de la Ne blina, Igarap Caf, V. Py-Daniel & U. Barbosa leg., 28.ix.1990 (INPA 1502a/1); ibidem, Pico de la Neblina, Cumbre do Pico, 3,014 m, V. Py-Daniel & U. Barbosa, 2.x.1990 (INPA 1517/2). Drymaeus rex Breure, 2009 (Fig. 107S) Description: e shell is up to 40.7 mm, 2.2 times longer than wide, with a white line below the suture and typically with three interrupted spiral colour bands of chestnut – to blackish brown, crossing weaker axial streaks of a less intense colour. Aperture with a white, slightly expanded lip, bordered pink inside. Genitalia. See Breure (2009: g. 7). Ecology. Found in Brocchinia plants. Distribution. Venezuela, Edo. Amazonas, Cerro de la Neblina and various localities near Pico Phelps and Pico Maguire; typi cally at elevations of 1,800–2,100 m, but recorded as low as 200 m on the northwestern side of Cerro de la Neblina. Types in RMNH and UF (284726, holotype). New record: Brazil, Edo. Amazonas, Pico de la Neblina, Ig arap Caf, V. Py-Daniel & U. Barbosa leg., 28.ix.1990 (INPA 1502b/1) Olympus nimbus Simone, 2010 (Fig. 107Q) Description: e shell is up to 15 mm wide with a height/ width ratio of 0.9, spire dome-shaped and relatively well de veloped, sculptured with a regular mosaic of uniformly spaced nodules, each row intercalated with neighbouring rows, with about 4–5 spiral rows on the penultimate whorl and the last whorl is smooth; colour beige, with three spiral, narrow bands split into spots which are fairly uniformly and equidistantly distributed. Aperture semicircular, compressed by penultimate whorl; umbilicus very narrow. Anatomy. See Simone (2010). Distribution. Brazil, Edo. Amazonas, So Gabriel da Cach oeira, Cachoeira do Tucano, at 100 m elevation. Type material in MZSP (87151, holotype). Fig. 109: Parsimonous tree of Pantepui Plekocheilus species, based on the characters given in Tab. 12, using traditional search with equal weights in TNT. t. b n b nn n

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3.1.5. Morphological and phylogenetic analyses Morphological analysis divided the Plekocheilus species into dierent sub-groups, based on several characteristics of their external shell morphology (Tab. 12). ey were then analysed under parsimony using TNT. e results in Figure 109 show that (1) Plekocheilus (P.) species are more derived than P. (Eury tus) species; and (2) with the sole exception of P. nebulosus, the species occurring on the western tepuis are more derived than those on the eastern ones. Phylogenetic analyses of CO1 sequences were performed only on Plekocheilus species. ese comprised seven taxa; two from Pantepui, three from Colombian and Venezuelan Andes and two from the West Indies (Fig. 110). e maximum likelihood analy ses resulted in a tree (log-likelihood – 3987.16), where the three Andean species are basally placed. e support values are, how ever, relatively low (bootstrap < 50 / Chi2 0.94 / SH 0.66). e Pantepui/West Indian taxa appear as a well-supported group (89 / 1 / 0.97), in which the two Pantepui taxa are more basal. A net work analysis of this molecular data indicates a reticulate paern (Fig. 111); however, internal nodes in split graphs are not necessar ily equivalent to those in a bifurcating tree and hence reticulation in these graphs may only be seen as an indicator of phylogenetic complexity rather than diagnostic of specic evolutionary events (Winkworth et al., 2005; Huson & Bryant, 2006). Although the limited taxon sampling does not allow further conclusions, the grouping of the Pantepui taxa corroborates the results of the morphological analysis. Additional analyses with other species from this genus should clarify the intra-generic relationships. 3.1.6. Discussion Shell morphology was the prime characteristic used to divide Plekocheilus into sub-genera. All sub-genera occur in the Pantepui region, with the exception of the Andean P. (Aeropictus) , but the highland species all belong to P. (Plekocheilus) and P. (Eurytus) . A more in-depth analysis of the paerns, found amoung dier ent Plekocheilus taxa, reveals that groupings based on external shell morphologies do not always coincide (Breure, unpublished data). Moreover, there are some taxa showing characteristics that may be aributed to two dierent subgenera (Borrero & Breure, 2011). e anatomical work done for this study generally corrob orates the data by Breure (1978), showing that two groups may be distinguished by their radula structure. However, the radula of P. vlceki shows that the dierences between the two groups may be more transitional than previously thought (Breure, 1978). e overall conclusion related to Pantepui Plekocheilus taxa is that there appears to be insucient available data to test any biogeographical hypothesis. At the same time, it is notable that the complexity indicated in the phylogenetic network analysis in Figure 111 is reected in the morphological data. In addition, the limited data on Drymaeus taxa does not war rant conclusions at this time. However, it is interesting that a Fig. 110: Maximum likelihood tree of Plekocheilus species, based on CO1 sequences (GenBank accession numbers mentioned behind the taxon names); Chi2-based parameter respectively SH-like Approximate Likelihood-Ratio Test values are presented as node values. Scale bar in substitutions per site. –

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preliminary phylogenetic analysis shows that D. rex appears quite basal in the tree of analyzed Drymaeus taxa (Breure, unpublished data). No anatomical or molecular data is available for the only non-Orthalicoid highland taxon, Columbinia exul , to be able to ascertain its relationships within the Clausiliidae. When we restrict ourselves to the ‘true’ Pantepui species [ex cluding lowland species such as Olympus nimbus and Plekocheilus (Eudolichotis) sinuatus ], the biodiversity of the land snails is strikingly large compared to the general situation in Venezuela (Fig. 112). e total summit area of the tepuis is 12,290 km 2 (Huber, 1995: p. 61), and this is just 1.4 % of the area of Ven ezuela. is gure includes tepuis where no snails are known, and when this area is restricted to the tepuis mentioned in this paper (4,060 km 2 ), it amounts to 0.05% of the Venezuelan terri tory. e number of land snails on the tepuis, however, accounts for 15% of the known Venezuelan malacofauna (Fig. 112D; see also Martnez, 2003). It must be noted that the Venezuelan ter restrial malacofauna is relatively poorly known and appears not to be very biodiverse (Breure & Mogolln, 2010: g. 1). Comparing orthalicoid and other species in the Pantepui area, the relative dominance of the former group is apparent (Fig. 112B vs. 112C). Given the specic acidic habitats found in the Pantepui highlands, the relatively high biodiversity of snails in this still under-explored area is quite remarkable. However, it Fig. 111: A split tree inferred from the same sequences as in the previous gure, showing the relationships between the dierent lineages (A); bootstrap percentages of the reticulate central pattern, with 95% con dence values shown in bold lines (B). Fig. 112: Pantepui versus Venezuela as a whole. A – Area (Pantepui area equals total summit area of tepuis, cf. Huber, 1995). B – Total number of Orthalicoidea species (this study). C – Total number of non-Orthalicoid land snails (adapted from Martnez, 2003). D – Total number of land snails. t. b n b nn n

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must be noted that while Orthalicoidea are relatively large spe cies that non-malacologists can easily nd, it is fully expected that the relative importance of other groups will increase when the area is beer explored by malacologists. 3.2. MAJOR GROUPS OF AQUATIC INSECTS OF PANTEPUI 3.2.1. Introduction Aquatic fauna of the Guyana region follows the general paern of the high level of endemism on the summits of tepuis (Spangler & Faitoute, 1991; niampor & Kodada, 1999; Issa & Jae, 1999; Kodada & Jch, 1999; De Marmels, 2007; Derka et al., 2009; Maier & Spangler, 2011; Nieto & Derka, 2011). e summits bear dierent types of aquatic habitats, from phytotelmata and temporary pools in bare rocks to large wetland meadows and medium sized rivers. Black water streams with bedrock bot toms, cascades and waterfalls and long and deep pools are the most common types of running waters (Fig. 114A–C). e total absence of a hyporheic environment is also a typical aribute of Pantepui streams (Figs. 113B–D, 114A,C,E). Another important factor is the very low water retention capacity of watersheds, which is responsible for wide discharge uctuations (Derka, pers. observation). Moreover, these streams are also extremely oligotrophic and low in minerals (conductivity usually ranges between 10 and 20 -1 ). ey are acidic (pH=3.5–5.5) and they can contain high concentrations of organic compounds leached from vegetation (Lnczos et al., 2007; Aubrecht et al., 2011). e streams ow through the quartzite caves at Chur Tepui and Mt. Roraima (e.g. mda et al., 2008 a ). But even at the most visited and explored tepuis of Mt. Roraima, Auyn Tepui or tepuis in Chimant Massif, aquatic insects were insuf ciently studied. In addition, important components of aquatic ecosystems such as algae have been studied only during the last decade (Fukov & Katovsk, 2009; Katovsk et al., 2011). Entire insect orders were practically unknown from the plateaus. For example, although mayies are a common part of the stream ecosystems (Derka et al., 2012), the rst mayy records from Chimant Massif and Mt. Roraima have been published only recently (Derka et al., 2009). is is also true for stoneies, pre viously unknown in the Pantepui Province (Derka et al., 2010). Records of other aquatic insect groups have now been published; – Fig. 113: Aquatic habitats on Chur Tepui: A – Helocrene springs of Western River (C10). B – Middle reaches of Western River (C9). C – Quebrada Lila (C1), typical spring stream with bedrock bottom. D – Ro Olinka (C5) with bedrock bottom.

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including Orthoptera (Issa & Jae, 1999; Derka & Fedor, 2010), Heteroptera (Spangler, 1986), Trichoptera (for a review see Derka & Zamora-Muoz, 2012), Coleoptera (Spangler, 1981, 1985; Spangler & Faitoute, 1991; niampor & Kodada, 1999; Kodada & Jch, 1999; Maier & Spangler, 2011; Kodada et al., 2012), Diptera (Barrera et al., 1989; Harbach & Navarro, 1996). One of the best studied groups is the order Odonata, thanks to numerous articles by the Venezuelan specialist Jurg Carl De Marmels (e.g. De Marmels, 1983, 1985, 1988, 1990, 1992, 1994, 1999, 2007). Odonata is considered to be the rst group of aquatic insects described from the tops of Mt. Roraima and Mt. Duida (Needham, 1933; Needham & Fischer, 1940; Klots 1944). e study of Cerro de la Neblina organized by Charles Brewer-Caras (Brewer-Caras, 1988) was a great contribution to investigation of aquatic fauna, and is responsible for the majority of information on Pantepui fauna. Although Cerro de la Neblina is not a typical tepui with a at summit isolated by sheer clis, it has similar geological and climatic conditions to the other tepuis (Brewer-Caras, 1988), and therefore, specimens sampled above 1,500 m a.s.l. should be aributed to the Pantepui Province. Numerous new taxa from there have been described from the material of aquatic insects collected during various expeditions. ese descriptions were published by Spangler (1985, 1986), Savage (1987), Flint et al. (1987), Holzenthal (1988), Schmid (1989), Johanson & Holzenthal (2004), Hamilton & Holzenthal (2005) and Maier & Spangler (2011). Although Venezuelan cave fauna comprises more than 500 species, only three aquatic insect orders have been reported from Venezuelan caves to date; (1) Hemiptera, genera Microvelia , Rhagovelia (fam. Veliidae) and Brachymetra (fam. Gerridae); (2) Diptera from the families Tipulidae, Psychodidae and Chi ronomidae; and (3) Coleoptera from the families Dytiscidae, Hydrophilidae, Dryopidae and Elmidae (Galn & Herrera, 2006; Kodada et al., 2012). Since the majority of biospeleological re search has been carried out in karst systems, there is almost a complete lack of information available from the recently discov ered quartzite caves (e.g. Vignoli & Kovayik, 2003). e rst data on aquatic insects from the Venezuelan quartzite caves was published by Charles Brewer-Caras (in mda et al., 2005 h ). is included the unique record of mayies in a stream in the re cently discovered Cueva Charles Brewer. e author mentioned “one species of Ephemera ying in dimness near where the river emerges from the cave”. Obviously, this was not a member of the genus Ephemera , but some dierent unidentied mayy, which Derka et al. (2009) later identied as an undescribed member of the genus Massartella. Derka et al. (2009, 2010) reported mayies (Ephemeroptera) and stoneies (Plecoptera) from Cueva Charles Brewer and from other caves at Chur Tepui. ese articles and the above mentioned report of Brewer-Caras in mda et al., (2005 h ) are considered to be the rst reports of mayies and stoneies in Venezuelan caves. Orthoptera is a terrestrial insect order found there with representatives of the Gryllidae, Palangopsidae and Rhaphidiophoridae families, as reported by Galn & Herrera (2006). Although this last group was oen seen during our explorations in the Chur Tepui and Mt. Roraima caves, the collected material remains unidentied. e same is true for other aquatic invertebrates, e.g. Turbellaria (Fig. 115F). Issa & Jae (1999) described a new genus Hydrolutos comprising four species from four tepuis, unique within orthop terans, having a plastron-like structure on the pleuro-sternal area of their thorax and abdomen. Derka & Fedor (2010) described a further species, Hydrolutos breweri (Anostostomatidae), from Cueva Charles Brewer. Recently, new still unidentied material was collected in Cueva del Tigre in the vicinity of Santa Elena de Uairn (Derka, unpublished data). Aquatic fauna of the Pantepui caves and spring streams is mostly composed of cold stenotherms, intolerant to elevated temperatures. Meanwhile, the fauna found in larger shallow streams (Figs. 113B,D, 114A–C), in wetlands with stagnant water (Figs. 113A, 114D) and in the temporary pools on tepuis’ plateaus is assumed to be adapted to high diurnal thermal uctuations. Research herein contributes to the knowledge of the Pantepui aquatic fauna, with special aention paid to the inhabitants of cave and spring streams. Study focuses on mayies, stoneies, caddisies, beetles of the Elmidae family and orthopterans from the genus Hydrolutos , and also reviews assembled information concerning Pantepui Ephemeroptera, Plecoptera and Trichop tera. Previously, this information was scaered throughout dif ferent articles, especially in the case of Trichoptera (Derka & Zamora-Muoz, 2012). 3.2.2. Material and methods Qualitative samples were taken by a 0.5 mm mesh kick net and by individual collection from stones and woody debris. Winged adults were collected by entomological net, individually collected from foam accumulations in streams, and also by light trapping. Some mayy nymphs were reared to subimagos and adults dur ing our eld work. Collected material was xed in 97% ethanol. Morphological characters were studied and photographed under stereomicroscopes and microscopes. e material was identied using works of Domnguez et al. (2006) for mayies, Stark et al. (2009) for stoneies and Angrisano & Sganga (2009 a ) for caddis ies. Additional articles regarding particular taxonomical groups used for material identication are cited in the relevant sections. Electric conductivity (EC) and pH values were measured in the eld using the WTW pH/Cond 340i SET eld device. Stream variables, including their mean width, depth, boom substrate and water temperature were measured at each sampling locality. 3.2.3. Sampling area and localities A total of 24 localities were sampled at Chur Tepui, Mt. Roraima and Auyn Tepui. Localities R1, R5, R6, A1 and A2 (see below) were not situated directly on the Mt. Roraima and Auyn Tepui plateaus, but on the tepuis slopes at altitudes above 1,500 m a.s.l., which is the low altitudinal limit for the Pantepui (Berry et al., 1995). erefore, all the following localities belong to the Pantepui Province. Auyn Tepui is the largest of the sampled tepuis, with a total surface area of 700 km 2 . It is the lowest one, with sampling localities situated between 1,700 and 1,851 m a.s.l. e next biggest is Chur Tepui with a summit area of 47.5 km 2 and altitudes 2,100 to 2,400 m a.s.l. Chur Tepui is one of the 12 tepuis forming the Chimant Massif, which has a total summit t. b n b nn n

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area of 623 km 2 and the slope area of 915 km 2 (McDiarmid & Donnelly, 2005). Mt. Roraima is the smallest and the highest one with a summit area of approximately 36 km 2 and altitudes from 2,700 to 2,800 m a.s.l. Sampling localities at Chur Tepui (C), Mt. Roraima (R) and Auyn Tepui (A) were: (C1) Quebrada Lila (Fig. 113C) – astream on the plateau above Cueva Charles Brewer, Chur Tepui plateau, 26. I. 2009, altitude 2,250 m a.s.l., N 05 14 57.6W 62 01 36.5, pH = 4.35, EC =14 -1 , T = 14 C, depth 0.02 – 1.5 m, width 1 – 3 m. is is a cascade stream shaded by surrounding forest. It has a bedrock boom with occasional deposition of gravel and stones, and submerged tree roots and mosses. (C2) Cueva Charles Brewer – Chur Tepui plateau, 15. I. 2009, altitude ca 2,200 m a.s.l., pH = 4.58, EC = 9 -1 , T = 14 C, depth 0.02 – 1.5 m. is stream has a bedrock boom with scaered deposition of gravel and stones. (C3) Spring streams below Cueva Charles Brewer – Chur Tepui plateau, 17. I. 2009, altitude ca 2,200 m a.s.l., pH = 4.5, EC = 9 -1 , T = 13.6 C. is has a bedrock boom with occasional deposition of gravel and stones in some places . (C4) e stream above Pozo Capuchino – Chur Tepui plateau, 15. I. 2009, altitude ca 2,200 m a.s.l., T = 15C, depth up to 1.8 m, width 2 – 6 m. It has a bedrock boom with deposition of sand, woody debris, and with submerged roots. (C5) Ro Olinka (Fig. 113D) – a stream over the waterfall above Cueva Juliana, 28. I. 2009, Chur Tepui plateau, altitude 2,115 m a.s.l., N 05 14’ 40.9” W 62 02’ 05.5”, pH = 4.48, EC = 9 -1 , T = 17 C, depth up to 1 m, mostly up to 0.2 m, river bed width 10 – 15 m. is has a bedrock boom with occa sional deposition of gravel and stones and patches of moss. is stream has wide and frequent discharge uctuations. Its bed is almost entirely dry during low discharge periods and water is then restricted to transverse crevices and pools connected to almost arid streams. (C6) Cueva Juliana – Chur Tepui, 23. I. 2009, altitude 2,300 m a.s.l., pH = 4.38, EC = 18 -1 , T = 14.3 C, depth up to 0.5 m, width = 0.3 – 1 m. is shallow stream ows inside the cave, and it has a bedrock boom with some sand accumula tions and stones. (C7) Spring stream below the waterfall at Ro Olinka emanating from Cueva Juliana – Chur Tepui, 20. I. 2009, altitude ca 2,100 m a.s.l., T = 14.3 C, depth 0.01 – 0.3 m, width 0.3 – 1 m. is has a bedrock boom with some coarse gravel deposits, mosses and roots. (C8) Ro Rojo – Chur Tepui, 20. I. 2009, altitude ca 2,100 m a.s.l., pH = 3.3, EC = 25 -1 , T = 17.5 C, depth up to 1.5 m, mostly up to 0.2 m, river bed width 1 – 4 m. is has a sandy bed with tree roots, woody debris and stones. (C9) Middle reach of the Western River (Fig. 113B) – Chur Tepui plateau, 24. I. 2009, altitude 2,399 m a.s.l., N 05 15 39.8W 62 00 44.0, pH = 4.56, EC = 11 -1 , T = 22.4 C, depth up to 1.5 m, mostly up to 0.1 m, width 0.1 – 1.5 m. is reach has a bedrock boom, and it forms pools with small deposits of gravel and stones and submerged tree roots. (C10) Springs of the Western River (Fig. 113A) – Chur Tepui plateau, 23. I. 2009, altitude ca 2,400 m a.s.l., pH = 3.75 – 4.58, EC = 2 – 17 -1 , T = 16.8 – 17.6 C, depth 0.1 – 0.7 m, width 0.2 – 1.5 m. ese consist of pools in a wetland meadow connected by small rapids, and they possess an abundance of cyanobacteria and macrophyta, and also occasional stones. (C11) Pools in wetlands in the northern part of Chur Tepui – Chur Tepui plateau, 22. I. 2009, altitude 2,438 m a.s.l., N 05 16 12.6W 62 00 58.8, pH = 2.7, EC = 46 -1 , T = 27.8 C, depth up to 0.3 m. is is a peat-swamp meadow with carnivorous plants, and there are abundant cyanobacteria in these scaered pools. (C12) Cueva Colibr – Chur Tepui, 26. I. 2009, altitude ca 2,300 m a.s.l. is is a shallow stream owing inside the cave, with a bedrock boom and some accumulations of sand and stones. Although there is no further available data, this is con sidered similar to C2 and C6. (R1) Tun Deuta – is is aspring stream below the southwestern wall of Mt. Roraima at “La Rampa”, 4. II. 2009, altitude 2,346 m a.s.l., N 05 09 58.0W 60 46 72.4, pH = 4.76, EC = 19 -1 , T = 14.1 C. e stream emanates through a small waterfall in the Mt. Roraima wall. e stream boom is covered with boulders, stones and moss, and it is surrounded by a cloud forest. (R2) Tun Dam – Mt. Roraima plateau, 6. II. 2009, alti tude 2,700 m a.s.l., N 5 10 17.34 W 60 45 37.74, T = 16.8 C, pH = 5.05, depth 0.05 – 0.5 m, width 1m. e stream ows through a small cave below the path to Punto Triple, and its bed is covered with stones and quartz crystals. (R3) Cueva de los Pmones – Mt. Roraima plateau, 4. II. 2009, altitude ca 2,700 m a.s.l., T = 12 C, pH = 4.78, depth up to 0.5 m, width 0.3 – 3 m. Stream ows inside the cave, and it has a bedrock boom with accumulations of sand, gravel and stones. (R4) Spring stream in a crevice close to Tun Dam – Mt. Roraima plateau, 7. II. 2009, altitude ca 2,700 m a.s.l., T = 14.3 C, depth to 0.3 m, width 0.5 – 1 m. is has a stony boom. (R5) e spring stream at “La Rampa” on Mt. Roraima, approximately 100 metres below the plateau – Mt. Roraima massif, 7. II. 2009, altitude ca 2,600 m a.s.l., T = 13.1 C, depth up to 0.3 m, width up to 1 m. e stream also has a rocky boom. (R6) Stream above the Mt. Roraima Base Camp – 7. II. 2009, altitude 1,840 m a.s.l., T = 16 C, width 2 m, depth up to 0.8 m. is stream is entirely shaded by a dense cloud forest. Stream bed comprises stones and boulders, and there are sand accumulations in its pools. (A1) Tun Terciopelo – a stream ca 20 min below El Pen Camp, Auyn Tepui, 7. I. 2010, altitude 1,733 m a.s.l., N 5 44’ 23.3” W 62 32’ 18.5”, T = 16.5 C. is is a montane stream in a cloud forest, with its boom covered by stones and gravel. (A2) Quebrada El Pen in El Pen Camp – Auyn Tepui, 7. I. 2010, altitude 1,832 m a.s.l., N 5 44’ 40.4” W 62 32’ 29.7”, T = 14.6 C, width 2-5 m. is is also a montane stream in a cloud forest and it has a bedrock boom. Its pools have gravel and leaf accumulations and also submerged tree roots. (A3) Springs of Ro Churn (Fig.114A) – Auyn Tepui plateau, 8. I. 2010, altitude 1,851 m a.s.l., N 5 46’ 15.1” W 62 32’ 7.9”, T = 25.4 C, width = 15 – 20 m. is is restricted to a small stream during low water discharges, while the rest of the bed is just an arid bedrock boom. –

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t. b n b nn n Fig. 114: Aquatic habitats on Auyn Tepui (A-C) and Mt. Roraima (D-E): A – Upper reaches of Ro Churn (A3). B – Ro Churn (A6), long and deep pools. C – Ro Churn (A5) in very dry period. D – Wetlands on Mt. Roraima plateau, biotop of Odonata (Anisoptera) nymphs. E – Typical small stream on Mt. Roraima plateau.

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(A4) Ro Oso in El Oso Camp – Auyn Tepui plateau, 9. I. 2010, altitude 1,733 m a.s.l., N 5 47’ 1.4” W 62 32’ 12.5”, T = 14.9 C, width 2 – 4 m. It has a bedrock boom, it is surrounded by tepui forest, and it forms numerous pools with stones, woody debris and tree roots. (A5) Ro Churn ca 30 minute walk above El Oso Camp (Fig. 114C) – Auyn Tepui plateau, 10. I. 2010, altitude ca 1,740 m a.s.l., T = 21.1 C, width 18 – 20 m. Again, this has a bedrock boom, and it is almost entirely dry during low water discharges. It is restricted to pools and transverse crevices con nected to a rather small stream. (A6) Ro Churn close to El Lecho Camp (Fig. 114B) – Auyn Tepui plateau, 10. I. 2010, N 5 49’ 34.6” W 62 32’ 27.9”, altitude 1,730 m a.s.l., T = 19.7 C, width 6 – 15 m, depth up to 2 m. is is a montane river with long, deep pools and bedrock ries. e pools have bedrock and sandy booms, covered with a lot of woody debris. 3.2.4. Ephemeroptera Introduction e order Ephemeroptera is a small, almost cosmopolitan group of hemimetabolous insects. It comprises more than 3,000 de scribed extant species in 42 families and more than 400 genera (Barber-James et al., 2008). Ephemeroptera is the oldest extant order of winged insects with fossils dating to the Carboniferous and Permian periods (Barber-James et al., 2008). ey are unique among insects, as they have two winged stages, subimago and imago. Most of the mayy life is spent in water in the immature stages of nymphs. e length of nymphal development varies from a few months to more than two years, depending on the spe cies and environmental conditions (Barber-James et al., 2008). e nymphs feed on algae and detritus, with only a few species being predators; and non-feeding adults depend on nymphal reserves. ey live for only a few hours or days, long enough to full mating, oviposition and dispersal functions. Nymphs play an important role in processing organic maer in aquatic ecosystems, and they provide a vital food source for sh, and for predaceous aquatic organisms including insects. Winged stages serve as prey for birds, bats, insects and spiders. eir highest generic diversity is in the Neotropics, with correspondingly high species diversity (Barber-James et al., 2008). South America has a unique mayy biota comprising 14 families, over 100 genera and more than 450 species, with high endemism at dierent taxonomic levels (Domnguez et. al., 2006). Precise knowledge of Venezuelan mayy fauna is very limited; only 33 species repre senting 20 genera and six families have currently been reported (Chacn et al., 2009). is low number reects the history of collection rather than the actual taxa richness. Recently, vari ous new taxa have been reported and/or described (Derka et al., 2009; Chacn et al., 2010; Molineri et al., 2011; Nieto et al., 2011; Nieto & Derka, 2011, 2012). e majority of these new nds came from Gran Sabana region. Derka et al. (2009) described the new species Massartella hirsuta (Leptophlebiidae) (Fig. 115D) and reported the occurrence of two Massartella species from Mt. Roraima and Chur Tepui which have not currently been described. Molineri et al. (2011) described two new species; the Caenis tepuinensis (Caenidae) and the Macunahyphes pemonensis (Leptohyphidae), and reported for the rst time in Venezuela Coryphorus aquilus Peters, 1981, Amanahyphes saguassu Salles & Molineri, 2006 and Tricorythopsis yucupe Dias, Salles & Ferreira, 2008. Nieto et al. (2011) reported 4 genera ( Cryptonympha, Har pagobaetis, Spiritiops and Zelusia), and 9 species found for the rst time in Venezuela. ese ndings doubled the recorded number – Fig. 115: A – Nymph of Fittkauneuria adusta (Ephemeroptera, Oligoneuriidae). B – Nymph of Parakari auyanensis (Ephemeroptera, Baetidae). C – Nymph of Parakari churiensis (Ephemeroptera, Baetidae). D – Nymph of Massartella hirsuta (Ephemeroptera, Leptophlebiidae). E – Larvae of Helicopsyche sp. (Trichoptera, Helicopsychidae) in their natural environment, Ro Olinka, Chur Tepui. F – Unidetied aquatic Turbellaria from Cueva Charles Brewer sector.

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of species and genera of Baetidae in Venezuela. However, the knowledge of mayies from the Pantepui Province still remains very limited. Published records are mainly based on sampling from already mentioned expeditions to Cerro de la Neblina. Some records and species descriptions are from localities below the Pantepui low altitudinal limit. ese include the description of Miroculis nebulosus (Savage, 1987), two new Farrodes species (Domnguez et al., 1996), and also records of Miroculis kaui (Savage, 1987) and Hagenulopsis minuta (Peters & Domnguez, 2001). e following three species were reported or described from localities over 1,500 m a.s.l.: Miroculis bicoloratus (Savage, 1987), Hagenulopsis minuta (Peters & Domnguez, 2001) and Fikauneuria carina (Pescador & Edmunds, 1994). Derka (2002) described Massartella devani from a stream on Mt. Roraima plateau and Nieto & Derka (2011) published a new Baetidae genus Parakari with two species endemic to Chur Tepui and Auyn Tepui. In addition, Nieto & Derka (2012) described new Spiritiops species in streams on the Chur and Auyn tepuis and Mt.Roraima. us, the number of mayy species known from the Pantepui now totals seven, and Derka et al. (2012) have sum marized all the published results, together with the rst author’s own research on Pantepui mayies. Results and discussion Although mayy nymphs are a common component of the aquatic communities in the Chur and Auyn tepuis plateau streams, they are rarely found on the Mt. Roraima plateau. Representatives of the Baetidae and Leptophlebiidae families were discovered on the tepuis plateaus, and Fikauneuria adusta nymphs from the family Oligoneuriidae were found in a stream on Auyn Tepui. Facts concerning the distribution of these taxa in the study area and supplementary ecological information is presented (explanatory note: N – nymph). Family Baetidae Leach, 1815 e family Baetidae has almost cosmopolitan distribution and it currently includes almost 100 genera worldwide. In South America, this family now encompasses 28 genera and more than 130 species (Nieto, 2010; Nieto & Derka, 2011; Salles et al., 2010). Most genera were described in the last decade of the 20th century, with Parakari being the last genus described from this region (Nieto & Derka, 2011). e Baetidae nymphs inhabit a variety of lotic and lentic habitats with sandy, rocky or organic substrates. ere are representatives of 7 genera found on the tepuis’ plateaus. Genus Baetodes Needham and Murphy, 1924 e genus, including more than 40 species, is recognized in North, Central and South America (Nieto et al., 2011). Of these, 27 species are described from South America, making it one of the most species rich genera in the Neotropics (Domnguez et al., 2006; Salles & Polegao, 2008; De Souza et al., 2011). Four species are known from Venezuela (Nieto et al., 2011). Although the nymphs are very abundant in streams on Auyn Tepui plateau, especially in sections with a strong current, they were absent on Chur Tepui and Mt. Roraima plateaus. Material examined: Baetodes sp.: A2 – 2N, A4 – 6N, A5 – 239N, A6 – 175N, R6 – 18N. Genus Callibaetis Eaton, 1881 is genus has a distribution from North America to Argen tina. In South America, 16 species are recognized from adults, especially female imagos, but associated nymphs were found in only 8 cases (Nieto, 2008; Cruz et al., 2009). Blanco-Belmonte et al. (2009) reported this genus from Orinoco and Caura rivers. Nymphs occur in dierent habitats, generally with lentic waters. ese were found in pools in streams on both Chur Tepui and Auyn Tepui, and constituted unique but abundant mayy rep resentatives in pools in peat-swamp meadows on Chur Tepui. Material examined: Callibaetis sp.: C1 – 1N, C3 – 1 sub imago, C9 – 3N, C10 – 36N, C11 – 7N, A6 – 53N. Genus Camelobaetidius Demoulin, 1966 is genus is widely distributed in North, Central and South America, with 29 species in the laer area (Boldrini & Salles, 2009). Five species have been recorded in Venezuela (Nieto et al., 2011), and nymphs from this genus are easily recognizable by spatulate tarsal claws with a fan-shaped row of denticles. is is a unique characteristic among Neotropical mayies. Material examined: Camelobaetidius sp.: A4 – 7N, A6 – 5N. Genus Cloeodes Traver, 1938 Cloeodes enjoys a widespread pantropical distribution in South, Central and North America, in Africa, Madagascar, Southeast Asia and Australia. Seventeen species have been reported from South America (Nieto & Richard, 2008), with one of these in Venezuela (Nieto & Emmerich, 2011; Salles & Cavalcante do Nascimento, 2009). Material examined: Cloeodes sp.: C1 – 5N, 1 , 1 ; A1 – 1N; A2 – 1N; A3 – 94N; A4 – 7N; A6 – 4N; R6 – 2N. Genus Parakari Nieto & Derka, 2011 Nieto & Derka (2011) described this genus from material col lected on Chur Tepui and Auyn Tepui plateaus (Figs. 115B–C, 116A). e only other recorded material was P. auyanensis , found in the stream below Salto Angel which is the highest waterfall on Earth, cascading 979 m from Auyn Tepui plateau. Recently, Derka (unpubl.) found Parakari nymphs in the stream at Roraima foothills and at locality R6. Nymphs have habitats ranging from spring streams to larger mountain rivers, and they were discov ered in a stream inside Cueva Charles Brewer. ey apparently tolerate a wide range of temperatures, from oligostenothermal cave streams possessing a stable temperature around 14 C to wide and shallow streams with high diurnal thermal uctuations. Material examined: Parakari churiensis : C1 – 91N, 3 , 12 , 11 subimagos, 3 subimagos; C2 – 167N, 1 , 8 subimagos, 10 subimagos; C3 – 1N, 1 , 3 , 7 subima gos, 7 subimagos; C4 – 52N; C5 – 1N; C6 – 3N; C7 – 15N; C10 – 1N; Parakari auyanensis : A1 – 5N, A2 – 14N, A4 – 21N, A5 – 17N, A6 – 31N. Genus Spiritiops Lugo-Ortiz & McCaerty, 1998 is monotypical genus was described from nymphs, before Salles & Nieto (2008) described the adult from Brazil. S. silvu dus was reported from Brazil, Colombia, Surinam and French Guiana (Domnguez et al., 2006), and more recently, Nieto et al. t. b n b nn n

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(2011) found these nymphs in streams in Gran Sabana region of Venezuela. One undescribed species was also found in streams at all three tepuis, and it was described by Nieto & Derka (2012). Nymphs inhabit a wide range of streams but they prefer habitats with strong currents, even in waterfall cascade zones. Material examined: Spiritiops tepuiensis : A1 – 18N; A2 – 23N; A3 – 6N; A4 – 236N, 1 subimago; A5 – 35N; A6 – 124N; R1 – 6N; R5 – 6N; R6 – 86N; C1 – 22N, 15 ; C3 – 1 subimago, 1 subimago; C4 – 70N; C5 – 39N, 1 ; C6 – 8N; C7 – 9N; C9 – 5N. Family Leptohlebiidae Banks, 1900 is is the most diverse mayy family in the Neotropics. It includes approximately 40 genera and more than 150 species from South America, all belonging to the subfamily Atalophle biinae (Domnguez et al., 2006). In Venezuela, 19 species have been reported from 8 genera (Chacn et al., 2009; Derka et al., 2009). More recently, Blanco-Belmonte et al. (2009) added 4 genera and one undescribed genus. Genus Hagenulopsis Ulmer, 1920 Eight species of this dipterous genus are currently recognized, with ve of them from South America (Domnguez et al., 2009). However, only H. minuta is known from Venezuela (Chacn et al., 2009). Peters & Domnguez (2001) redescribed this spe cies, and they reported nymphs and male adults from the 140 m a.s.l. Cerro de la Neblina base camp, and also a male adult from 1,800 m a.s.l. Material examined: Hagenulopsis sp.: C1 – 1 , 1 , 1 sub imago; C2 – 1N; C4 – 1N; C8 – 7N; R6 – 3N; A4 – 1N. Genus Massartella Lestage, 1924 is genus is known from 5 described species, 2 of which live in Brazil and 3 in Venezuela (Derka et al., 2009). One unde scribed species was also reported from north-eastern Argentina (Pescador & Peters, 1990). Derka (2002) described M. devani from Mt. Roraima (R1). Later, this species was found in other streams at Roraima foothills. Material collected on Mt. Roraima plateau and at locality R5 is from an undescribed species. Mas sartella nymphs and adults collected at dierent localities of Chur Tepui belong to a further undescribed species (Fig. 116C). is species was oen sampled at the entrance of Cueva Charles Brewer (Boca de Mamut). Numerous remnants of adults were seen in spider webs deep in Cueva Charles Brewer, where they were compelled to y in absolute darkness. Nymphs were also collected in other caves on Chur Tepui. Another undescribed species was sampled at Auyn Tepui and also in a stream below Salto Angel. In the Pantepui, these Massartella nymphs exclu sively inhabit the cold stenothermal streams with temperatures ranging from 14 to 18 C. ey prefer pools in streams where they can hide underneath rocks and stones. Female subimagos (Fig. 116C) were observed ying before sunset. Material examined: Massartella devani : R1 – 12N, R6 – 1N; Massartella sp.1: R2 – 52N; R3 – 5N; R4 – 6N; R5 – 9N; Massartella sp.2: C1 – 18N, 7 ; C2 – 25N, 2 , 8 , 1 subimago, 3 subimagos; C3 – 3N, 1 , 2 subimagos, 2 subimagos; C4 – 2N; C5 – 1N; C6 – 23N; C7 – 10N; C12 – 70N; Massartella sp.3: A1 – 13N; A2 – 27N; A3 – 3N, 1 subimago; A4 – 30N, 1 subimago; A5 – 7N; A6 – 4N. Genus Miroculis Edmunds, 1963 e genus Miroculis currently has 15 described species in a distribution area which ranges from northeastern Argentina to Trinidad (Domnguez, 2007; Peters et al., 2008; Salles & Lima, 2011). ree species have been recorded in Venezuela (Savage, 1987). M. nebulosus Savage, 1987 and M. kaui Savage & Peters, 1983 were collected at the Cerro de la Neblina base camp at 145 m. a.s.l. Meanwhile, Peters et al. (2008) recorded M. nebulosus in Serrana de Chiribiquete in Colombian Amazonia which belongs to the Guyana Shield. Savage (1987) also described Pantepui species M. bicoloratus from Camp II at Cerro de la Neblina (ca 2,100 m a.s.l). e material collected on both Chur and Auyn tepuis is similar to M. bicoloratus , but it belongs to a dierent undescribed species. Material examined: Miroculis sp.1: C1 – 9N, 2 , 2 subimago, 2 subimagos; C2 – 1N; C10 – 2N; Miroculis sp.2: A5 – 23N, 3 ; Miroculis sp.3: R6 – 3N. Family Oligoneuriidae Ulmer, 1914 Among 6 genera of the family documented from the South America, the genus Fikauneuria is the only one known from Venezuela. Genus Fikauneuria Pescador & Edmunds, 1994 Two species are known from this genus; (1) F. adusta Pescador & Edmunds, 1994 is described from southeastern Venezuela and northern Brazil, and it is relatively common in small streams in Gran Sabana region (Fig. 115A). Although it was not recorded on tepuis plateaus, it has been sampled above 1,800 m a.s.l.; and (2) F. carina Pescador & Edmunds, 1994 was sampled in various streams at Cerro de la Neblina at altitudes ranging from 750 to 1,820 m a.s.l. (Pescador & Edmunds, 1994). Both these species can therefore be aributed to Pantepui Province. Material examined: Fikauneuria adusta : A1 – 4N, R6 – 1N. 3.2.5. Plecoptera Introduction Plecoptera, is a small order of hemimetabolous insects with about 3,500 described extant species in 16 families with 286 genera (Fochei & Tierno de Figueroa, 2008). Stoney adults have two pairs of large membranous wings which are sometimes reduced or absent, and almost equal-sized fore and hind wings which fold horizontally over and around the abdomen when they are at rest. e nymphs resemble adults, possessing a closed tracheal system with or without lamentous gills. Plecoptera nymphs are aquatic and they live mainly in cold, well-oxygenated running waters, although some species can also be found in lakes. However, the increasing number of stoneies described from the tropics and their high rate of endemicity modies the common belief that Plecoptera are cold-water specialists, and suggest that the actual hot spots of Plecoptera biodiversity are tropical areas (Fochei & Tierno de Figueroa, 2008). e main factors responsible for their high endemic rate are the ecological requirements of nymphs, –

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t. b n b nn n Fig. 116: A – Nymph of Parakari churiensis (Ephemeroptera, Baetidae) in a trap of Utricularia humboldti, Chur Tepui. B – Female imago of Spiritiops tepuiensis (Ephemeroptera, Baetidae) from Chur Tepui. C – Female subimago of an undescribed species of Massartella (Ephemeroptera, Leptophlebiidae) from Chur Tepui. D – Pupae of Zumatrichia sp. (Trichoptera, Hydroptilidae), Chur Tepui. E – F – Nymph of Kempnyia (Plecoptera, Perlidae) from Cueva Colibr (Charles Brewer Cave System) with reduced ocelli and partial depigmentation of the compound eyes.

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and adults’ reduced ight capacity. eir life cycle lasts one or more years, but there are also bi – or tri-voltine species. ese nymphs represent a very important component of stream eco systems in terms of biomass and diversity of ecological roles. ey feed on detritus, periphyton, aquatic invertebrates and small vertebrates as collectors, scrapers, shredders and predators. Adults live for days or weeks and their diet can include pollen, lichens and cyanobacteria, although the adults of the largest species do not seem to feed. Females lay their eggs on water (Fochei & Tierno de Figueroa, 2008). e currently recognized stoney fauna of South America, comprising approximately 380 species, is poor and it does not represent their actual diversity (Fochei & Tierno de Figueroa, 2008; Stark et al., 2009). Only these three Plecoptera genera have been recorded in Venezuela: Anacroneuria , Macrogynoplax and Enderleina (Derka et al., 2010), and they all belong to the Perlidae family. is family accounts for ten Neotropical genera (Stark, 2001; Hamada & Marques Couceiro, 2003; Stark et al., 2009). Although Plecoptera were previously unknown in Pantepui, the following data from tepuis has now been published; (1) from Mt. Roraima; Enderleina pre clara by Jewe (1960); and (2) from Pico de la Neblina; Ender leina inti and E. yano by Stark (1989), Macrogynoplax neblina and M. spangleri by Stark & Zwick (1989), and Anacroneuria blanca , A. cruza , A. baniva , A. pequea , A. menuda , A. vistosa , A. shamatari and A. pinza by Stark (1995). However, since all this material was collected at foothills it cannot be aributed to the Pantepui Province. Recently, Derka et al. (2010) published the rst records of stoneies from Pantepui. ey found nymphs from the genera Macrogynoplax and Kempnyia at Chur Tepui, and the Kempnyia nymphs in the Tun Deuta stream on Mt. Roraima. It was the rst record of the genus Kempn yia in Ven ezuela. Derka et al. (2010) observed the total absence of ocelli in one Kempnyia nymph with dierent degrees of ocelli reduction, and partial compound eyes depigmentation in others (Fig. 116E, F). ese were especially noted in nymphs from Cueva Colibr on Chur Tepui, where these characteristics were aributed to their cavernous habitat. Stoney ndings from Chur Tepui and Mt. Roraima published by Derka et al. (2010) are reviewed herein, together with new data from Auyn Tepui. Comments on distribution of these taxa in the study area and ecological information are given below (explanatory note: N – nymph). Results and Discussion One highlight here is total absence of the most common and most widely distributed Neotropical genus Anacroneuria from streams on Mt. Roraima and Chur Tepui summits. Also, it is only recently that Anacroneuria nymphs were recorded on Auyn Tepui. Stoneies were collected almost exclusively in caves and oligostenothermal spring streams originating in the caves. Al though Anacroneuria nymphs were found in medium sized rivers, they were always hidden in shaded and cooler habitats below the river banks. It is quite surprising that no stoney nymphs were recorded on the Mt. Roraima plateau, because the waters at these higher altitudes were the coldest, and would have provided suitable habitats for them. Poor macroinvertebrate communities and therefore the lack of suitable prey is probably the reason of absence of stoney nymps in streams on Mt. Roraima plateau. Genus Anacroneuria Klaplek, 1909 is is the most diversied and widely distributed genus of the Neotropical Perlidae, reaching to the Nearctic Region. It has more than 300 species distributed from the SW of the USA to northern Argentina (Stark et al., 2009). Specic recognition of these nymphs is very dicult, and in many cases it is impossible because so few of them have been described. Material examined: A2 – 13 N, 1 imago, 1 imago, A5 – 14N; A6 – 12N. Genus Macrogynoplax Enderlein, 1909 With 14 described species, this genus is distributed in Brazil, Guyana, Peru, Surinam, Venezuela and also Colombia (Froe hlich, 1984; Stark, 1996; Stark & Zwick, 1989; Ribeiro-Ferreira & Froehlich, 1999; Bispo et al., 2005; and Ferreira Ribeiro & Rafael, 2007). Identication of nymphs at the species level is not possible at the moment. Material examined: C2 – 1 imago and its exuvia, C6 – 2N, C7 – 2N, A1 – 3N, A2 – 1N. Genus Enderleina Jewe, 1960 is genus is distributed in northern Brazil and Venezuela (Stark et al., 2009). Five species have currently been described: E. preclara Jewe, 1960, E. inti Stark, 1989, E. yano Stark, 1989, E. bonita Stark, 1989 and E. oehlichi Ribeiro-Ferreira, 1995. e three laer species were described from individuals collected in Venezuela (Stark, 1989; Ferreira Ribeiro & Rafael, 2005; Stark et al., 2009). e type locality of E. preclara is Brasilian part of Mt. Roraima, at altitudes around 2,100 m a.s.l., so their pres ence is also expected in Venezuela. It is impossible to identify Enderleina nymphs at the species level with current knowledge, and although this genus was not collected, we expect it to inhabit the Pantepui Province. Genus Kempnyia Klaplek, 1914 is genus includes 35 species, and it was previously known only from Brazil (Stark et al., 2009; Froehlich, 2011 a, b ) until Derka et al. (2010) published the rst records of the genus in Venezuela. e nymphs are oligostenothermal insects, mainly inhabiting mountain streams (Froehlich, 1981), but identica tion at the species level is not yet possible. Material examined: A2 – 1N, C2 – 1N, C7 – 2N, C12 – 2N, R1 – 3N. 3.2.6. Trichoptera Introduction e order Trichoptera (caddisies) comprises a group of ho lometabolous insects closely related to the Lepidoptera. It in cludes more than 13,000 extant species within 45 families and approximately 600 genera (Holzenthal et al., 2007; de Moor & Ivanov, 2008). e adults are moth-like terrestrial insects with wings covered by hairs, not scales as in Lepidoptera. e adult Trichoptera ranges in size from minute with a wing span of less than 3 mm to large with a wing span approaching 100 mm (de Moor & Ivanov, 2008). Larvae are best known for the transportable cases and xed shelters that many, but not all, –

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species construct. Similar to Lepidoptera, Trichoptera larvae spin silk which they use for constructing their retreats and larval cases. Silk has enabled Trichoptera larvae to develop numer ous morphological adaptations for their ecological diversity and the success of this order. Larvae and pupae are important components of food webs in the rivers, lakes and streams which they inhabit (Wiggins, 2004; Holzenthal et al., 2007; de Moor & Ivanov, 2008). Approximately 2,100 species from 148 genera have been reported in the Neotropics, and 69% of the (sub-) genera are endemic (de Moor & Ivanov, 2008). According to Johanson & Holzenthal (2004), the Venezuelan Trichoptera fauna has almost 240 described species, of which 90% are in the following 6 families: Helicopsychidae (14 spp.), Hydrobiosidae (20 spp.), Hydroptilidae (49 spp.), Hydropsychidae (57 spp.), Leptoceri dae (27 spp.), and the Philopotamidae (46 spp.). Records and species descriptions of the Venezuelan caddisies are scaered throughout 40 publications (Holzenthal & Cressa, 2002), with most of these based on material collected and described by O. S. Flint Jr. (cited in Flint et al., 1999). Since the frequency of new species in some regions of the Neotropics can reach 75% of all collected species, the recorded Venezuelan Trichoptera fauna certainly underestimates the actual number of species, which could reach well over 500 (Holzenthal & Cressa, 2002). Records of Trichoptera in Pantepui are mainly based on material collected on the Cerro de la Neblina expeditions of the 1980’s (Flint et al., 1987; Flint, 1998; Holzenthal, 1988; Schmid, 1989; Blahnik, 1997; Johanson & Holzenthal, 2004; Hamilton & Holzenthal, 2005; Chamorro & Holzenthal, 2010). Species ndings and descriptions have also been published from four other tepuis: Mt. Roraima (Ross & King, 1952; Holzenthal, 1986), Auyn Tepui (Flint et al., 1987), Ptari Tepui (Schmid, 1989) and Mt. Duida (Flint et al., 1987). A total of 23 species from 8 genera and 6 families have currently been published from Pantepui (Derka & Zamora-Muoz, 2012). e highest number of species were located in Cerro de la Neblina – 16 spp. from 7 genera and 6 families (Derka & ZamoraMuoz, 2012): Helicopsychidae: Helicopsyche ( Feropsyche ) suc cinta Johanson & Holzenthal, 2004; H. ( Feropsyche ) laneblina Jo hanson & Holzenthal, 2004; Hydrobiosidae: Atopsyche ayacucho Schmid, 1989; A. ayahuaca Schmid, 1989; A. chimuru Schmid, 1989; A. chinchacamac Schmid, 1989; A. huallaripa Schmid, 1989; Hydropsychidae: Leptonema neblinense Flint, McAlpine & Ross, 1987; L. amazonense Flint, 1978; Leptoceridae: Triplec tides tepui Holzenthal, 1988; Polycentropodidae: Polycentropus neblinensis Hamilton & Holzenthal, 2005; Polyplectropus ama zonicus Chamorro & Holzenthal, 2010; P. intorum Chamorro & Holzenthal, 2010; Philopotamidae: Chimarra ( Curgia ) ensifera Flint, 1998; Ch. ( Curgia ) medioloba Flint, 1971; and Chimarra ( Chimarrita ) neblina Blahnik, 1997. ree species from 2 genera and 2 families have been reported from Mt. Roraima (Derka & Zamora-Muoz, 2012): Hydrobi osidae: Atopsyche iana Mosely, 1949; A. hamata Ross & King, 1952; and Leptoceridae: Notalina roraima Holzenthal, 1986. Two Hydrobiosidae species are known from Ptari Tepui (Derka & Zamora-Muoz, 2012): Atopsyche atahuallpa Schmid, 1989, and A. calahuaya Schmid, 1989. Also, one Hydropsychidae species was found on Auyn Tepui: Leptonema guayanense Flint, McAlpine & Ross, 1987 and another one on Mt. Duida: Lep tonema ramosum Flint, McAlpine & Ross, 1987. In addition to these, the genus Austrotinodes Schmid, 1955 from the family Ecnomidae, with trans-Antarctic distribution from Australia to the Neotropics (omson & Holzenthal, 2010), was described by Flint & Denning (1989) from Cerro de la Neblina. ey have described A. fuscomarginatus at 760 m a.s.l. and A. neblinensis at 140 m a.s.l., and although this genus has not been located in the Pantepui, its occurrence there is quite likely. Results and Discussion e Calamoceratidae, Hydroptilidae, Odontoceridae and Seri costomatidae families have been recorded for the rst time in the Pantepui, together with the following nine genera: Phylloicus (Calamoceratidae), Blepharopus , Macrostemum (Hydropsy chidae), Orthotrichia , Oxyethira , Zumatrichia (Hydroptilidae), Oecetis , Nectopsyche (Leptoceridae) and also the unidentied genus of Sericostomatidae ( Notidobiella ?). However, the genus Polyplectropus from Cerro de la Neblina was not recorded in the Pantepui. e lowest genera richness was found in Mt. Roraima, where there were only 4 genera from 4 families recorded. Similar genera richness was observed on Chur Tepui, with 8 families and 13 genera, and Auyn Tepui with 9 families and 13 genera. Odon toceridae and Philopotamidae were absent on Chur Tepui, while Calamoceratidae and Sericostomatidae were lacking at Auyn Tepui. Comments on the distribution of these taxa in the study area and notes on the diagnostic features of some of them follow (explanatory notes: L – larva, P – pupa). Family Calamoceratidae Ulmer, 1906 is is a cosmopolitan family with approximately 175 de scribed species in 8 genera (Holzenthal et al., 2007). Adults are more diurnal in their activity than most Trichoptera (Flint et al., 1999). e larvae are large caddisies, ranging in length up to 25 mm, and they have dierent ways of constructing their portable tubes. For example, Phylloicus has quadrate panels of leaves or bark fastened together at lateral seams, thus forming a aened cylinder (Wiggins, 2004). Meanwhile, the Neotropi cal species’ larvae inhabit tranquil backwater areas of streams and rivers where they feed on detritus (Flint et al., 1999). Two genera are recorded from Venezuela: Banyallarga Navs, 1916 which is limited to the Andes (Prather, 2004), and Phylloicus Mller, 1880 in the Guyana region (Prather, 2003). e om nivorous larvae of Banyallarga mainly build their tubular cases from mineral fragments combined with other materials, while detritivorous larvae of Phylloicus have at cases composed of leaves (Flint et al., 1999). Genus Phylloicus Mller, 1880 is is a Neotropical genus of 57 extant species, with several species extending their range to the southwestern United States (Prather, 2003; Moreira Santos & Nessimian, 2010; Quinteiro et al., 2011). Prather (2003) reviewed this genus, describing 4 new species at Cerro de la Neblina, located between 140 and 760 m a.s.l.: P. amazonas , P. cordatus , P. elektoros and P. passulatus . t. b n b nn n

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Although this author reported P. fenestratus Flint, 1974 at 1,250 m a.s.l., no specimens have been collected above 1,500 m a.s.l. Material examined: Phylloicus sp. C2 – 1 . Family Helicopsychidae Ulmer, 1906 e snail-case caddisies (Fig. 115E) of this cosmopolitan family comprise 250 species; the Neotropics alone host almost 100 species (Flint et al., 1999; Holzenthal et al., 2007; Johanson & Holzenthal, 2010), while mainland South American fauna includes 41 species (Johanson & Malm, 2006). e larvae of the genus build remarkable helical, sand-grain cases so similar to snail-shells that early workers described these insects as mol luscs. All helicopsychid larvae feed as scrapers on periphyton and other organic maer on exposed rock surfaces (Fig. 115E). ey inhabit dierent environments, from springs to lowland rivers and wave-washed shores of lakes and thermal springs, but they can also occur in hyporheic zones (Wiggins, 2004). All American Helicopsychidae are from the Helicopsyche genus, and are divided into two subgenera: Helicopsyche ( Feropsyche ) Johanson, 2002 and Helicopsyche ( Cochliopsyche ) Mller, 1885. Feropsyche has 86 described species (Johanson, 2002; Johanson & Holzenthal, 2004, 2010), and it is the largest subgenus, while Cochliopsyche comprises 16 species (Johanson, 2003). Genus Helicopsyche von Siebold, 1856 ere are 24 Helicopsyche species known from Venezuela (Johanson & Holzenthal, 2004). Four species were sampled at Cerro de la Neblina: Helicopsyche ( Feropsyche ) neblinensis and H. ( Feropsyche ) linabena were collected at altitudes of 140 – 760 m a.s.l., while H. ( Feropsyche ) succinta and H. ( Feropsyche ) laneblina were collected exclusively at 1,690 – 1,950 m a.s.l., and thus these are true Pantepui species. Cochliopsyche subgenus, however, was not noted in the Pantepui (Johanson, 2003). Material examined: Helicopsyche form 1: C1 – 2L, C2 – 10L, C7 – 15L, A2 – 24L, R2 – 20L, R4 – 30L, R5 – 28L, 2P; Heli copsyche form 2: C1 – 4L, C4 – 12L, 10 empty cases, C5 – 25L, P, C7 – 1L, A4 – 80L; Helicopsyche form 3: C2 – 20 empty cases, A1 – 30L, A2 – 1L, A4 – 13L, A5 – 54L, A6 – 70L; Helicopsyche ( Feropsyche ) sp. nov. 1: R2 – 2 ; Helicopsyche ( Feropsyche ) sp. nov. 2: A2 – 5 , 1 ; Helicopsyche ( Feropsyche ) sp. nov. 3: C4 – 11 , 1 ; Helicopsyche ( Feropsyche ) sp. nov. 4: A4 – 2 ; C5 – 38 , 7 . Family Hydrobiosidae Ulmer, 1905 Hydrobiosidae represent the Gondwanaland equivalent of Rhyacophilidae, and these are restricted to Neotropical and Australasian biogeographic regions. Only a few species in each region have distribution extending into Oriental, Palearctic, or Nearctic regions (Holzenthal & Cressa, 2002; Holzenthal et al., 2007). Schmid (1989), who reviewed the world fauna, considered that there are approximately 50 recognized genera, and most generic diversity is concentrated in either the Chilean subregion of the Neotropics or in the Australasian region. ere are 168 species in 22 (23) genera described from the Neotropics, and while all but 2 are endemic to the Chilean subregion (Flint et al., 1999; de Moor & Ivanov, 2008), only the genus Atopsyche occurs in Venezuela (Holzenthal & Cressa, 2002). Larvae do not possess cases, and they live as predators restricted to running waters (Wiggins, 2004). Genus Atopsyche Banks, 1905 e genus Atopsyche , contains more than 120 species, and it is the largest genus of the family. It is widespread in the Neotrop ics, except for the Chilean subregion, and it extends north to Central America, Mexico and the southwestern United States (Holzenthal et al., 2007). In Venezuela, the majority of the 23 known species are largely restricted to the higher elevations of the Andes or the Guyana Highlands (Schmid, 1989; Holzenthal & Cressa, 2002). e rst known Pantepui species was Atopsyche iana Mosely, 1949 described from Guyana and the Brazilian parts of Mt. Roraima plateau (Ross & King, 1952). Still the same year, these authors also published description of A. hamata from this area. e following 7 Pantepui species from Venezuelan Guyana were described by Schmid (1989): A. atahuallpa and A. cala huaya (Ptari Tepui at 1,800 m a.s.l.); A. ayacucho , A. ayahuaca , A. chimuru , A. chinchacamac and A. huallaripa , above 2,000 m a.s.l. at Cerro de la Neblina. Material examined: Atopsyche spp.: C1 – 25L, 1 ; C2 – 3P, C3 – 2L, C4 – 3L, C5 – 7L, C6 – 2L, C7 – 4L, C8 – 2L, C9 – 7L, 3 P, C10 – 2L, C11 – 3L, R2 – 8L, R3 – 6L, 2P, A1 – 3L, A4 – 7L, A5 – 5L, A6 – 9L; Atopsyche sp. nov. 1: A2 – 2 , A4 – 16 , 2 , Atopsyche sp. nov. 2: A2 – 1 ; Atopsyche sp. nov. 3: C2 – 1 , 2 , 2 P, 1 P. Family Hydropsychidae Curtis, 1839 e Hydropsychidae family has approximately 1,500 de scribed species. It is the third largest family in the order Trichop tera and the most diverse of the net-spinning annulipalpians (Holzenthal et al., 2007). Hydropsychids’ nets are aached to rocks in owing waters and are used to capture detritus or microorganisms from stream. Hydropsychid larvae are oen quite abundant and important lter-feeders in streams (Wiggins, 2004). e following eight genera are recorded in Venezuela: Blepharopus Kolenati, 1859; Centromacronema Ulmer, 1905; Leptonema Gurin, 1843; Macronema Pictet, 1836; Macrostemum Kolenati, 1859; Plectromacronema Ulmer, 1906; Smicridea McLa chlan, 1871; and Synoestropsis Ulmer, 1905 (Flint et al., 1999). In addition to these, Smicridea caligata Flint, 1974 was reported from Kanarakuni in the Jaua Jid-Sarisariama Massif foothills at 450 m a.s.l., and S. marlieri Flint, 1978 was found in Puerto Ayacucho (Flint, 1978). Finally, four Leptonema species have been published from the Pantepui Province (Flint et al., 1987). Genus Blepharopus Kolenati, 1859 is is a monotypical genus. B. diaphanous Kolenati, 1859 is known from Argentina, Brazil and Venezuela (Flint et al., 1999), and larva and pupae of this species were described by Flint & Wallace (1980). Material examined: Blepharopus sp.: A6 – 2 L. Our sampled early-instar larvae clearly dier from the known species. Genus Leptonema Gurin , 1843 e genus Leptonema contains more than 125 species, largely –

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in the Neotropics, but also in Africa, Madagascar and south western United States (Holzenthal et al., 2007). More than 100 species are widespread in the Neotropics (Flint et al., 1987, 1999; Flint, 2008), and the following 4 species were recorded at the Pantepui: L. guayanense Flint, McAlpine & Ross, 1987 from Ro Churn on Auyn Tepui, and L. ramosum Flint, McAlpine & Ross, 1987, sampled in 1929 during Tate’s expedition at Mt. Duida. Neither of these species is endemic in the Pantepui Prov ince, and both have large distribution areas: L. guayanense was sampled in Kanarakuni (450 m a.s.l.) and also in the foothills of Jaua Jid-Sarisariama Massif and Mt. Roraima and Auyn Tepui (Flint et al., 1987), while L. ramosum was recorded at La Escalera (Piedra de la Virgen), Salto Par at Ro Caura and Kanarakuni (Flint et al., 1987). Meanwhile, the remaining two species were recorded in the Pantepui Province at Cerro de la Neblina: L. neblinense Flint, McAlpine & Ross, 1987 sampled from 1,690 to 1,850 m a.s.l., and L. amazonense Flint, 1978 sampled from 140 to 1,820 m a.s.l. (Flint et al., 1987). At least these further 12 Leptonema species have been recorded in Venezuelan Guyana. e following ve of these were sampled and/or described at Cerro de la Neblina from 140 to 760 m a.s.l.; (1) Leptonema davisi Flint, McAlpine & Ross, 1987; (2) L. sparsum Ulmer, 1905; (3) L. irroratum Flint, 1974; (4) L. aterrimum Mosely, 1933; and (5) L. viridianum Navs, 1916. In addition, (6) L. lacuniferum Flint, 1978 was sampled in Bolvar State at La Escalera at 1,100 m a.s.l.; and (7 and 8) L. hirsutum Flint, 1974 and L. spinulum Flint, McAlpine & Ross, 1987 are known from Kanarakuni (450 m a.s.l.) but they have larger distribution areas. (9) L. aspersum Ulmer, 1905; (10) L. sancticaroli Flint, McAlpine & Ross, 1987; and (11) L. gadzux Flint, McAlpine & Ross, 1987 are known from San Carlos de Ro Negro, while (12) L. albovirens Walker, 1852 is widespread in South America (Flint et al., 1987). Material examined: Leptonema sp.: A1 – 2L, A2 – 20L, A6 – 2L. Genus Macrostemum Kolenati, 1859 Although this is a widely spread genus in North and South America, Africa, and Asia, it was previously unknown in the Pantepui (Flint et al., 1999). e immature stages of the genus are rheophilous, therefore living in or on solid substrate (Flint et al., 1999). is genus has not yet been found in the Pantepui. Material examined: M. erichsoni Banks, 1920: C1 – 2 , 1 . Family Hydroptilidae Stephens, 1836 is family is commonly referred to as microcaddisies, be cause it has the smallest body size in this order, with adults ranging between only 1.5 and 5 mm. It is, however, the largest in species diversity with about 2,000 species on every habitable continent and on many remote islands (Holzenthal et al., 2007). It currently includes 28 genera and 290 species in South America (Angrisano & Sganga, 2009 b ). e larvae are highly diverse in form, habitat, and feeding behaviour. Most build cases of silk or sand, while some construct at, xed shelters and others are free-living until pupation (Wiggins, 2004). At least 18 genera have been recorded in Venezuela (Flint & Harris, 1992; Flint et al., 1999; Harris & Flint, 2002; Harris et al., 2002 a-c ; Wasmund & Holzenthal, 2007), but no data has been published from the Pantepui. Finds related to the Pantepui reported from Cerro de la Neblina at 140 m a. s. l were; (1) Neotrichia colmillosa Harris, 1990; (2) N. cuernuda Harris, 1990 (Harris, 1990); (3) N. cayada Harris & Davenport, 1992 (Harris & Davenport, 1992); (4) Alisotrichia neblina Harris & Flint, 2002 (Harris & Flint, 2002); and (5) Taraxitrichia ama zonensis Flint & Harris, 1992 (Flint & Harris, 1992). In addition, Wasmund & Holzenthal (2007) also described Rhyacopsyche otarosa from Cerro de la Neblina at 760 m a.s.l. and representatives of genera Flintiella Angrisano, 1995 and Orinocotrichia Harris, Flint & Holzenthal, 2002 are recorded from Ro Cataniapo and San Carlos de Ro Negro, with Oxyethira Eaton, 1873 from the Bolvar State (Flint et al., 1999; Harris et al., 2002 a,b ). Although three genera were clearly identied, some material requires more detailed study: C2 – 1 , C4 – 1 ; A2 – 1 , A4 – 2 . Genus Orthotrichia Eaton, 1873 Orthotrichia is a large genus with world-wide distribution. In the Neotropics, this genus has been reported from the Antilles, Panama, Ecuador and Peru (Flint et al., 1999). Material examined: Orthotrichia sp.: A2 – 25L, A4 – 3L, 3 , 3 . Genus Oxyethira Eaton, 1873 Oxyethira is a very large genus with world-wide distribution. eir larvae are well known because they build distinctive askshaped silken cases (Wiggins, 1996). Material examined: Oxyethira sp.: C9 – 40L, C10 – 7L, R2 – 4L. Genus Zumatrichia Mosely, 1937 Larvae of Zumatrichia are indistinguishable from Abtrichia Mosely, 1939 (Angrisano & Sganga, 2009 a ). However, Abtrichia is a small genus reported in southern Brazil, Uruguay and Argen tina, while Zumatrichia is a fairly large genus, which occurs from the United States through Central America and Lesser Antilles to northern areas of South America, including Venezuela (Flint et al., 1999). erefore, the collected larval material here is most likely from the genus Zumatrichia (Fig. 116D). Material examined: Zumatrichia sp.: C5 – 20L, 15P; A2 – 25L, 7P. Family Leptoceridae Leach, 1815 e Leptoceridae, or long-horned caddisies, are recognized by their long, narrow forewings and very long, liform anten nae. ey comprise one of the largest families in the order, with about 1,800 described species (Holzenthal et al., 2007). e larvae are found in a wide variety of habitats, including large and small rivers, cascades, and even in semiterrestrial habitats in both lowland and highland areas (Flint et al., 1999). ey construct a wide diversity of cases, perhaps the most diverse in the order. Cases are fundamentally tubular, but can be made entirely of silk secretions, of plant debris arranged spirally or laid transversely, or of large leaf fragments, which then form aened cases (Wiggins, 2004). Larvae feed as leaf detritus shredders, periphyton scrapers, predators, and they even feed on freshwater sponges. Fieen genera have been reported in South America, with seven of these endemic to the Neotropics (Flint et al., 1999; t. b n b nn n

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Holzenthal et al., 2007). e genera Achoropsyche Holzenthal, 1984; Atanatolica Mosely, 1936; Grumichella Mller, 1879; Nec topsyche 1879; Notalina Mosely, 1936; Oecetis McLachlan, 1877; and Triplectides Kolenati, 1859 have been recorded in Venezuela (Flint et al., 1999). While Notalina and Triplectides genera had previously been reported in the Pantepui (Holzenthal, 1986, 1988), Oecetis and Nectopsyche are recorded for the rst time. Genus Notalina Mosely, 1936 is genus has a trans-Antarctic distribution between Aus tralia and the Neotropics (Holzenthal et al., 2007). In South America, it comprises 10 described species placed in the subge nus Neonotalina. e genus is subdivided into two species groups; the braziliana and the roraima (Holzenthal, 1986; Calor, 2008; Calor et al., 2006). Calor & Froehlich (2008) described the im mature stages. e only record of the genus from the Pantepui was one N. roraima Holzenthal, 1986 male described from the Mt. Roraima plateau (Holzenthal, 1986). Material examined: Notalina sp.: C2 – 6L, 1 , A2 – 4L, R3 – 1L; N. roraima: R2 – 3 . Genus Triplectides Kolenati, 1859 Similar to Notalina , the genus Triplectides has a trans-Antarctic distribution between Australia and the Neotropics, with species occurring in New Caledonia, India, Southeast Asia and Japan (Holzenthal et al., 2007). More than 70 species are known, and 14 of these were recorded in South America (Holzenthal, 1988; Dumas & Nessimian, 2010). Holzenthal (1988) described T. nevadus from San Carlos de Ro Negro and T. neblinus and T. neotropicus from Cerro de la Neblina, at 140 and 760 m a.s.l. He also described T. tepui from Cerro de la Neblina (1,250 – 2,100 m a.s.l.) which is the only Pantepui representative of the genus. is species has also been recorded at 1,600 m a.s.l. in Ro Teuanen, north of Kavanayn in the Bolvar State. Material examined: Triplectides sp.: C4 – 34L, C8 – 4L, A2 – 1L, A4 – 5L. Genus Oecetis McLachlan, 1877 is is a cosmopolitan genus of more than 200 described species, with 22 known from South America (Rueda Martn et al., 2011). Two widely distributed species O. excisa Ulmer, 1907 and O. punctipennis Ulmer, 1905 were sampled in Cerro de la Neblina at 140 m a.s.l. (Rueda Martn et al., 2011). Material examined: Oecetis sp.: C4 – 2L, A6 – 1L. Genus Nectopsyche Mller, 1879 e New World genus Nectopsyche has approximately 57 de scribed species, with 48 known from South America and 10 from Venezuela (Flint et al., 1999). N. multilineata Flint, 1983 was collected in Caron River (Flint, 1983). Material examined: Nectopsyche sp.: C1 – 1 , 1 . Species identication was impossible because specimens were leached in ethanol and wing colour paerns are necessary for species-level classication. Family Odontoceridae Wallengren, 1891 is small family contains approximately 115 extant species in both the Old World and the New World (Holzenthal et al., 2007). ree genera occur in the Neotropics (Flint et al., 1999). Larvae live in springs and small to medium-sized streams and rivers, and some are associated with waterfalls. eir cases are made of sand grains or larger mineral fragments and are very resistant to crushing. e larvae themselves are omnivorous, feeding on detritus, vascular plants, moss, algae and aquatic arthropods (Wiggins, 2004). Genus Marilia Mller, 1880 e genus Marilia is worldwide distributed, with 53 extant species (Dumas & Nessimian, 2009), with its greatest diversity in the Neotropics; 33 species occur in South America and one in Venezuela (Flint et al., 1999; Dumas & Nessimian, 2009). Until our own data, no previous record was reported from the Pantepui. Material examined: Marilia sp.: A1 – 2L, A2 – 2L, 3 , 1 ; A3 – 5L, A4 – 35L, 1 ; A5 – 7 L, A6 – 85L. Family Philopotamidae Stephens, 1829 is is a cosmopolitan family with approximately 1,000 described species. ree of the ve genera recorded in South America are known in Venezuela: Chimarra Stephens, 1829; Chimarrhodella Lestage, 1925; and also Wormaldia McLachlan, 1865 (Flint et al., 1999; Holzenthal et al., 2007). Larvae con struct elongate tubular nets which are usually aached to the underside of rocks, and spin an extremely ne mesh inside the coarse outer supporting meshwork. Larvae feed on detritus and microorganisms ltered from water passing through the net (Wiggins, 2004). ree species of the genus Chimarra have been reported from the Pantepui (Blahnik, 1997; Flint, 1998). Genus Chimarra Stephens, 1829 is cosmopolitan genus is one of the largest genera in the order Trichoptera. It includes approximately 570 described spe cies, and many more which have not been described (Holzenthal et al., 2007). Flint (1998) revised the subgenus Curgia and de scribed and reported from the Pantepui two species: Ch. ( Curgia ) ensifera Flint, 1998, and Ch. ( Curgia ) medioloba Flint, 1971. Besides their Pantepui localities at Cerro de la Neblina 1,690 and 1,850 m a.s.l., both species have also been reported at 140 m a.s.l. Two additional species from the subgenus are known at 140 m a.s.l. at Cerro de la Neblina, and 2 species at La Escalera in the Bolvar State (Flint, 1998). Blahnik (1997) dened the new subgenus Chimarrita , and also described the Pantepui species Ch. ( Chimarrita ) neblina Blahnik, 1997 at Cerro de la Neblina (1,820 m a.s.l.). He reported and/or described two more species from the subgenus at lower altitudes at Cerro de la Neblina, and also two species from Tobogn de la Selva near Puerto Ayacucho. Blahnik (2002) dened the further new subgenus Otarrha and reported three species from Cerro de la Neblina at 140 m a.s.l. Material examined: Chimarra sp.: A2 – 1 . Family Polycentropodidae Ulmer, 1903 is is a large and diverse cosmopolitan family containing approximately 650 species in 26 genera (Holzenthal et al., 2007). e larvae are found in most types of waters, although –

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they are virtually absent from small, cold spring streams (Flint et al., 1999). Larvae construct a variety of nets, either as a larval silken retreat or as a capture net (Wiggins, 2004). Although most species are predators, they also ingest plant detritus (Flint et al., 1999). Six genera occur in South America, four of which have been recorded in Venezuela (Flint et al., 1999; Hamilton & Holzenthal, 2005). e widely distributed species Cyrnellus aternus (Banks, 1905) is the only representative of the genus Cyrnellus Banks, 1913 known from Venezuela. One species from the Polycentropus genus and two Polyplectropus species have recently been described in the Pantepui at Cerro de la Neblina (Hamilton & Holzenthal, 2005; Chamorro & Holzenthal, 2010). According to authors Chamorro & Holzenthal (2010), 12 spe cies have been recorded in Venezuela, 2 of these from Cerro de la Neblina in the Pantepui: Polyplectropus amazonicus (1,820 m a.s.l.) and P. intorum (1,450 – 2,100 m a.s.l.). Two additional Polyplectropus species were described by Chamorro & Holzenthal (2010) from lower altitudes at Cerro de la Neblina: P. guyanae at 140 m a.s.l. and P. maculatus between 140 and 760 m a.s.l. Finally, Polycentropus beccus from Puerto Ayacucho region was described by Hamilton & Holzenthal (2005). Genus Polycentropus Curtis, 1835 This is a cosmopolitan genus of more than 170 species (Holzenthal et al., 2007), with 102 species recognized in the Neotropics (Hamilton & Holzenthal, 2011). ere are 5 species known in Venezuela (Flint et al., 1999; Hamilton & Holzenthal, 2011). Here, one species, P. neblinensis Hamilton & Holzenthal, 2005 was described at 1,690 – 2,100 m a.s.l. at Cerro de la Ne blina in the Pantepui. Material examined: Polycentropus sp.: C1 – 15L, C2 – 12L, C4 – 10L, 1 , C8 – 1L, C9 – 13L, C10 – 3L, A2 – 1L, A4 – 2L, A6 – 7L. Family Sericostomatidae Stephens, 1836 is family contains 19 genera and approximately 100 species. In South America, four genera were considered endemic to south ern Chile and adjacent Argentina, and a further genus with the sin gle species Grumicha grumicha (Vallot, 1855) was considered en demic to southern and southeastern Brazil and adjacent Argentina (Flint et al., 1999; Holzenthal et al., 2007). However, Holzenthal & Blahnik (2010) described the new species named Notidobiella amazoniana from Ecuador and Amazonian Brazil. ese authors suggest that recent dispersal of the genus to northern tropical South America from Patagonia was followed by its subsequent diversication. is constitutes the rst record of this family in the Guyana region, and the northernmost record in South America. Material examined: Sericostomatidae indet: C7 – 1L, C5 – 4L. 3.2.7. Orthoptera Introduction Orthoptera are hemimetabolous insects and although these are not normally considered to be aquatic insects, some members are some-how linked to freshwater habitats, mainly through relationship with an aquatic plant host. Species which cannot develop without freshwater, especially for egg-laying and nymph development are considered to be primary inhabitants of fresh water biota (Amdgnato & Devriese, 2008). e freshwater Orthoptera community is mainly represented by Acridomorpha, Acridoidea. Among Ensifera, the predaceous Ensifera katydid genus Phlugis specialises on nymphs of aquatic grasshoppers in South America (Amdgnato & Devriese, 2008). e South American Hydrolutos species are medium-sized ightless anos tostomatids known from Venezuelan tepuis. As atypical almost fully southern hemispheric group of orthopterans, Anostostoma tidae are believed to owe their distribution to the split of Gond wanaland (Fleming, 1979; Gibbs, 2006). e genus Hydrolutos Issa & Jae, 1999 (Orthoptera: Anostostomatidae: Lutosinae) had the 4 species: H. auyan , H. chimantea , H. roraimae and H. aracamuni , described from four dierent tepuis in southeastern Venezuela (Issa & Jae, 1999). Derka & Fedor (2010) described the new species Hydrolutos breweri from Cueva Charles Brewer, and Derka & Fedor (2012) contributed an additional description of the female of this species. All these appear unique and unusual in their aquatic ecology, and their existence in this environment is enabled by aplastron-like structure on the pleuro-sternal area of the thorax and abdomen, which is generally unique in orthopterans. e external morphology is highly conserved in all species of this genus, as reported in the original description of Hydrolutos by Issa & Jae (1999). In body length, the species ranges between 38 – 54 mm in males and 38 – 62 mm in females, with the laer tending to be slightly larger than the males. All members of genus Hydrolutos have brown colouring and they are apterous and nocturnal. Results and Discussion Charles Brewer-Caras reported the occurrence of many 10 to 12 cm long individuals of the genus Hydrolutos in his eponymous newly discovered gigantic cave on Chur Tepui on the Chimant Massif, that submerged underneath the water in case of dan ger (mda et al., 2005 a ). Derka & Fedor (2010) described the new species, Hydrolutos breweri (Fig. 117A, B) from this Cueva Charles Brewer. Male genitals of the genus Hydrolutos were gured and described for the rst time. Like other members of the genus, H. breweri inhabits aquatic habitats, and many indi viduals were observed walking and swimming in the stream, and also walking outside the water at the oor and walls of this cave. eir powerful legs and tarsal claws enable them to cling tightly and also to move even against strong currents. Because of permanent darkness in this cave, individuals were active 24 hours a day, and not only nocturnally as in some members of this genus (Issa & Jae, 1999; Derka, pers. observ.). However, it can not be considered to be troglobiont because of the lack of the typical adaptations of eye reduction and colouring. Occur rence of this species can also be expected in other streams at Chur Tepui plateau outside Cueva Charles Brewer. We observed numerous individuals of H. roraimae in the cave systems of Mt. Roraima and H. auyan in the stream near the El Oso Camp site on Auyn Tepui. Digestive tract analysis of four specimens of H. breweri from Cueva Charles Brewer revealed plant and animal detritus, aquatic fungi hyphae and other animal remains iden tied as originating from Chironomidae larvae, mayies and stoneies. erefore, these observed specimens did not feed on t. b n b nn n

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– Fig. 117: A-B – Hydrolutos breweri from Cueva Charles Brewer. C – Jolyelmis auyana (Coleoptera, Elmidae) from Auyn Tepui. D – Roraima carinata (Coleoptera, Elmidae) from Mt. Roraima.

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algae as Issa & Jae (1999) reported for other Hydrolutos species, instead they had changed their diet in this environment which lacked light and algae. 3.2.8. Coleoptera Introduction Beetles are holometabolous insects, normally with adecticous, exarate pupae. Adults are characterized by a strongly sclerotized body with forewings hardened into elytra, which serve to protect the more delicate hind wings and the dorsal surface of the hind two thoracic segments (pterothorax) and abdomen. Beetles have the largest number of species in the entire animal world, with 400,000 currently described (Jch & Balke, 2008). Although the Coleoptera are one of the largest orders of ‘‘aquatic’’ animals containing approximately 18,000 aquatic species, this is a very small percentage and the majority are terrestrial. According to Jch & Balke (2008) approximately 12,600 (70%) were described prior to October 2005. About 30 beetle families have aquatic representatives, and in 25 families at least 50% of the species can be considered truly aquatic (Jch & Balke, 2008). e fol lowing six families are thought to include 1,000 or more aquatic species: Dytiscidae (3,908 described species/5,000 estimated), Hydraenidae (1,380/2,500), Hydrophilidae (1,800/2,320), Elmidae (1,330/1,850), Scirtidae (900/1,700) and Gyrinidae (750/1,000). e Neotropical region is home for 2,510 known species and 3,900 estimated species (Jch & Balke, 2008). Our study focused on the family Elmidae. is family has approximately 1,330 species in 146 genera (Kodada & Jch, 2005). Two subfamilies are currently recognized: Larainae (26 genera, 130 species), and Elminae (120 genera, 1,200 spe cies). Adults and larvae of all the species are considered aquatic, many Larainae species adults are oen encountered below or a lile above the water line, and also in spray zones of waterfalls and cascades. Of all the larger water beetle families, only the elmids appear to be exclusively conned to running water. Although the Neotropical region has approximately 360 de scribed Elmidae species, it still remains inadequately explored (Jch & Balke, 2008). Results and Discussion A few genera of Elmidae have been found at the studied tepuis, and three of these are identied: Roraima Kodada & Jch, 1999, Jolyelmis Spangler & Faitoute, 1991, and Gyrelmis Hinton, 1940. Subfamily Larainae LeConte, 1861 Larainae represent a small subfamily, which occurs in all major regions of the world. e Palearctic, Nearctic, Neotropic and Afrotropical faunas are reasonably well known, in contrast to those in Oriental and Australian regions. e species diversity appears highest in Afrotropical and Neotropic regions (Kodada & Jch, 2005). Eleven genera have been reported in the Neotrop ics (Kodada & Jch, 1999, Maier & Spangler, 2011). Adults are always associated with running waters. Most species can be regarded as true water beetles, and although many species can y readily and rapidly when disturbed, their larvae are considered to be strictly aquatic. Genus Roraima Kodada & Jch, 1999 e genus Roraima can be easily distinguished from all other known Larainae genera by the shape of the pronotum, elytral carinae and by the unique forking and fusion of the medial eld veins of the hind wing (Kodada & Jch, 1999). Roraima carinata (Fig. 117D) was described from R1. One Roraima species, which is yet to be described, was found in the streams at Chur Tepui and also at the entrance of Cueva Charles Brewer, while the second was found in Auyn Tepui streams. Material examined: Roraima carinata : R1 – 2 , 2 ; Roraima sp. 1: C1 – 4 adults, 4 larvae; C2 – 14 adults, 10 larvae; C5 – 3 adults, 4 larvae; C9 – 4 adults, 1 larva; Roraima sp. 2: A2 – 5 adults, 2 larvae; A4 – 7 adults, 10 larvae; A 5 – 6 adults, 7 larvae. Subfamily Elminae Curtis, 1830 e subfamily Elminae currently includes 119 genera with approximately 1,200 recognized species (Kodada & Jch, 2005). All Elminae species are regarded as true water beetles and there are no terrestrial or riparian representatives in this subfamily. Larvae are considered strictly aquatic, adults live exclusively in running water, which includes both hygropetric habitats and sub terranean streams, and they are seen quite rarely in wave-washed lake shores. eir preferred habitats are rapidly owing reaches of streams and rivers, and especially shallow ries and rapids. In these streams and rivers, they are found on stony substrates of varying grain size, including rocks, boulders, gravel and sand, as well as on dead wood, dead leaf accumulations and vegetation. Elminae exhibit several obvious morphological adaptations to their unusual habitat: the cuticle is very strongly sclerotized and the head is retractable into the prothorax to minimize injury when dislodged in the strong current; the legs are long and their claws are very large so that this strength enables them to cling rmly to substrates. Adults do not need to come to the surface to breathe, because they possess an incompressible gas gill or microplastron incorporating a very thin layer of air held by a dense coating of hydrofuge structures, which can replace oxygen through diusion of dissolved oxygen from the surrounding water, thus functioning as a physical gill (Kodada & Jch, 2005). Genus Jolyelmis Spangler & Faitoute, 1991 e genus Jolyelmis Spangler & Faitoute (1991) comprises one of the numerous South American elmid genera. It was estab lished on the single, very distinctive species of Jolyelmis auyana Spangler & Faitoute, 1991, which was collected from a cascade on Auyn Tepui. e most striking characteristics of the type species, Jolyelmis auyana, are three distinct longitudinal cari nae on the pronotum and each elytron and also carinae on the metasternum and the rst ventrite (Spangler & Faitoute, 1991). Two additional species, J. derkai niampor & Kodada, 1999, and J. reitmaieri niampor & Kodada, 1999, were discovered in a few small samples from streams crossing the footpath to Mount Roraima . In contrast to the type species, longitudinal carinae on these species are much less pronounced and less distinctive (niampor & Kodada, 1999) . Representatives of four species have been collected: Jolyelmis auyana was collected in Auyn Tepui (Fig. 117C); individuals of J. reitmaieri were found in Cueva de los Pmones; while the new Jolyelmis species specimens came t. b n b nn n

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from various streams on Chur Tepui plateau and the entance to Cueva Charles Brewer. ese were dened as J. spangleri by Kodada et al. (2012), who also described the larva of J. spangleri and J. reitmaieri . Material examined: J. derkai : R1 – 5 ; J. reitmaieri : R1 – 11 , 9 ; J. spangleri : C1 – 3 , C2 – 4 , C4 – 1 , C7 – 12 , 7 , C9 – 1 , 1 unsexed specimen. J. auyana : A2 – 3 adults, 2 larvae; A4 – 4 adults, 7 larvae; A5 – 8 adults, 1 larva. Genus Gyrelmis Hinton, 1940 ere are twelve Neotropical species currently recognized (Kodada & Jch, 2005). Representative of one, probably unde scribed species was collected at Chur Tepui. Material examined: Gyrelmys sp.: C1 – 1 , 1 3.3. HERPETOFAUNA OF THE “LOST WORLD” 3.3.1. Introduction Tepuis result from the erosion of a once extensive plain that was part of Gondwana, comprising South America, Africa and Ant arctica. eir impressive appearance resembles islands towering from their surrounds of pluvial forest and herbaceous savannas, and they are oen surrounded by clouds. In terms of evolution ary history, their isolation transforms the higher tepuis into isolated ecosystems with high speciation and endemism. e life that evolved in each tepui is unique, although some genera, and very occasionally, some species are shared with other tepuis. With regard to herpetofauna, each genus possesses one or more endemic species in each tepui. e herpetofauna of the tepuis is impoverished compared with its surrounding, which include endemics of the Guyana Shield with Amazon elements of wide distribution. In this part, we examine only a minimum selection of species inhabiting the summits of selected tepuis all over 1,000 m (Tab. 13). ere are some lower tepuis ranging from 650 m to 1,500 m a.s.l., but these generally have forested summits with few endemic elements. It is considered that endemic species exist only on the higher tepuis at 2,000 to 3,000 m a.s.l., without the possibility of existing elsewhere. Species above 1,000 m altitude are only considered here because Autana is a low tepui with 1,450 m summit, and fauna changes signicantly between its base and its summit. In all other respects, the higher tepuis in Bolvar State are usually treated dierently with highland fauna above 1,500 m being considered dierent to those below (see MacCulloch et al. 2007). While the eastern tepuis contain common lowland species to 1,000 m, only tepui summits of at least 2,000 m are considered here; with the single exception of Autana. 3.3.2. History of herpetological collections in the “Lost World” Expeditions to these remote sandstone tables, and especially their summits, are logistically dicult, expensive, and therefore scarce. Early explorations began at the end of the 19 th century, in 1894 and 1898, when E. Im urn and H. Perkins, and then F.V. McConnell and J.J. Quelch, ascended Roraima and collected botanical specimens. Some reptile and amphibian samples col lected on the slopes and summit went to the British Museum, where they were described by Georges Boulenger (1900). us, the rst described tepui species originated from the slopes and summit of Roraima. ese were: Oreophrynella macconelli, O. quelchii , Otophryne robusta, Riolama leucosticta (Fig. 121F), Neu sticurus rudis and Pristimantis marmoratus . Although Roraima is the most visited tepui, only two species of herps have been described since 1900, Anomaloglossus praderioi and A. roraima , although we know at least one additional species of Pristiman tis that is being described (McDiarmid & Donnelly, 2005; C. Barrio-Amors, in prep.). e rst specimens from the Auyn Tepui were collected during the Phelps Expedition with the American Museum of Natural History (AMNH) in 1937-38 (Roze, 1958 a ; Myers, 1997; Myers & Donnelly, 2008), and these laer authors also presented data from AMNH collections. e Chimant Massif was explored for the rst time by the Museum of Natural History of Chicago in 1955. e expedition led by botanist Julian Steyermark was able to access this massif only by foot. Roze (1958 b ) reported on herpetofauna, describ ing several new species. Gorzula (1992) presented results from years of collecting. In our three recent expeditions, we have now been able to observe a signicant portion of the herpetofauna inhabiting it. e only existing herpetological reports on Autana are, the description of Stefania breweri (Barrio-Amors & Fuentes, 2003; personal data), and the report of the presence of Cercosaura phelpsorum by Fuentez & Rivas (2000). Modern explorations of these tepuis began in the 1960s, when helicopters were used for the rst time to reach the otherwise inaccessible summits. Charles Brewer-Caras, the Michelangeli brothers, Oo Huber and a few other scientists are responsible for revealing some of the mysteries of the “Lost World” to the academic community, especially regarding its biota. However, the most fruitful herpetological collector in the tepui area has certainly been Stefan Gorzula, who used EDELCA helicopters in the 1980s to explore a great part of the sandstone summits of Bolvar and Amazonas states (Gorzula & Searis, 1999). Other herpetologists who have published their collections from Ven ezuelan tepuis are; Jos Ayarzagena, Celsa Searis, Charles Myers, Maureen Donnelly, Roy McDiarmid, Philippe Kok and the authors of this part of the volume. e following ve tepuis are described as examples: Autana, Auyn, Chimant, Roraima and Sarisariama (Tab. 13). 3.3.3. Results Cerro Autana e Autana sacred mountain has a peculiar shape (Fig. 118A). Due to its unique “tree stump” form, it has been worshipped from remote times by the Piaroa natives as the tree of life. e Piaroa and the Hiwi call it “Wahari-Kuawai” and “Caliebirri-nae” respectively (Brewer-Caras, 1972, 1976 a ). is small tepui is located 90 km to the South of Puerto Ayacucho in the Amazo nas State. It is composed of pink sandstone and runs south to –

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t. b n b nn n Tab. 13: Composition of the tepui herpetofauna treated in the text. It remains extremely complicated to formulate a list which includes all species inhabiting dierent altitudes. The inferior limit for Autana and Sarisariama is 1,000 m. a.s.l. For Auyn, Chimant and Roraima we consider the inferior limit at 1,500 m. a.s.l. Auyn Chimant Autana Roraima Sarisariama Amphibians Oreophrynella cryptica + O. macconelli + O. quelchii + Rhaebo guatus + Rhinella granulosa + Centrolene gorzulai + Hyalinobatrachium mesai + H. cappellei + + H. taylori + Anomaloglossus rufulus + A. moei + A. praderioi + A. roraima + A. tepuyensis + Dendrobates leucomelas + Stefania breweri + S. ginesi + S. riae + S. roraimae + S. schuberti + Hypsiboas a. crepitans + H. jimenezi + + H. roraima + + H. sibleszi + + + H. tepuianus + + Myersiohyla kanaima + Osteocephalus taurinus + Tepuihyla edelcae + + T. warreni + Ceuthomantis duellmani + Pristimantis auricarens + P. marmoratus + + P. sarisarinama + P. muchimuk + Pristimantis sp. 1 + Leptodactylus cf. lithonaetes + L. longirostris + + L. rugosus + L. sabanensis +

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– Auyn Chimant Autana Roraima Sarisariama Pseudopaludicola sp. + Otophryne robusta + + O. steyermarki + + Reptiles Gonatodes superciliaris + Norops carlostoddi + N. chrysolepis + + N. eewi + + N. ortonii + Plica a. plica + Tropidurus bogerti + T. hispidus + Tropiduridae sp. + Mabuya nigropunctata + + Anadia mcdiarmidi + Euspondylus auyanensis + Arthosaura montigena + A. tyleri + A. versteegii + Arthosaura sp. + Cercosaura phelpsorum + + Neusticurus rudis + + + + N. tatei + N. racenisi + Riolama leucosticta + Epictia albions + + Anilius scytale “phelpsorum” + Atractus guerreroi + A. steyermarki + Chironius fuscus + + Eryththrolampus aesculapii + Leptodeira annulata + + Mastigodryas boddaerti + Liophis ingeri + L. lineatus + L. torrenicola + L. trebbaui + + L. reginae a. semilineata + Pseustes poecilonotus + amnodynastes chimanta + Bothriopsis taeniata + +

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north for approximately 2.5 km 2 , culminating in its northern tower at 1,450 m. a.s.l. It is located at 04 52‘ N, 67 27‘ W. e Autana appears to be the remainder of the Sipapo-Cuao Mas sif which borders it, and geologically, it is part of the Roraima Supergroup (Colve, 1972, 1973). e vegetation at its summit is composed of a tepui grassy meadow, and the bushes there contain the dominant Kunhardtia rhodanta and Brocchinia hechtioides plants. e predominant temperature range at the summit is between 18 and 24 C. Few scientic expeditions have been carried out on the sum mit, and most of these have been by TV crews, as witnessed in the famous 1973 documentary by Flix Rodrguez de la Fuente for TVE (Spanish Television). Another expedition was carried out by the Radio Caracas TeleVision for its “Expedition” series, and this episode was called “Autana, the tree of life”. However, it was Brewer-Caras’s 1971 exploration expedition, with its mapping of the sandstone cave crossing the north tower of Autana, that have made Autana famous and created excitement throughout the scientic community. In his rst expedition in February 1971, Carlos Julio Naranjo collected a tree-frog that was described 32 years later, and eponymously named Stefania breweri aer Brewer. However, its morphological description remains the only thing known about this species, because there was only a single specimen, and despite all eorts it has never been sighted since (Barrio-Amors & Fuentes, 2003). It is interesting to note that Flix Rodrguez de la Fuente’s 1973 lm mentioned some specimens to be identied by the Spanish naturalist Dr. Javier Castroviejo. Although such identication was never performed, that documentary did highlight a speci men similar to the one collected later in 2000, and identied by Oswaldo Fuentes as Leptodactylus cf. lithonaetes . e only exhaustive scientic expedition to the Autana sum mit forms part of a work that is still in preparation, and this is based on the study of herpetofauna collections from the Cuao-Si papo Massif, including Sipapo, Cuao, Autana and Lago Leopoldo or “Paraka-Wachoi” Lake. ese collections were carried out in Lago Leopoldo and the Autana summit by Oswaldo FuentesRamos (OFR), aer the invitation of Charles Brewer-Caras in 2000. is expedition also included investigations in the Cuao-Sipapo Massif lowland areas and the Autana surrounds made by OFR and Cesar Barrio-Amors (CLBA), together with Santiago Castroviejo and Fernando Rojas. Since only the material collected by OFR at the summit of the Autana is of interest in this present work, the following specimens collected during that April 2000 expedition are recorded here; (1) Leptodactylus lithonaetes Heyer, 1995. Only several males observed, darker than in surrounding lowlands, under small stones, active near small pools; (2) Stefania breweri , despite an extensive day and night search, the only known endemic Autana frog, Stefania breweri , was not found; (3) Plica a. plica (Lin naeus, 1758) collected on a rock on the southern side (the species is a common element in pluvial forests throughout the entire Amazon); and (4) Cercosaura phelpsorum (Lancini, 1968) siing sunbathing one morning at the base of a Brocchinia hechtioides on the edge of a cli (Fuentes & Rivas, 2000). is was its rst sight ing outside its typical locality of Cerro Yav (Myers & Donnelly, 1996). Taxonomic controversy currently remains concerning the small tepui lizards Cercosaura goelei and C. phelpsorum , and this will most likely continue until new specimens from several tepuis are collected and their DNA analyzed. Two snakes were also collected on Autana’s summit: Liophis reginae a. semiline ata with dark colouration and Epictia albions , collected under a small rock on the edge of the Cerro Autana. Auyn Tepui Auyn Tepui, located at 05 55‘ N, 62 32‘ W, is without doubt the tepui which has aracted the most aention throughout the scientic world (Fig. 118B, C). It covers 715 km 2 , and reaches 2,450 m. a.s.l. in height, and despite being the most studied tepui, the complexity and diversity of its ora and fauna en sures that decades will pass before its herpetofauna is completely identied and understood. is tepui is also reknowned for the information contained in Myers & Donnelly (2008) whose work remains an excellent reference for details of its macro and microhabitats, and also for its herpetofauna. e history of the interest in Auyn Tepui begins with Jimmy Angel’s romantic and exaggerated histories and the bold eorts to nd a fabulous mine of gold at its summit. In his aerial exploration, Angel glimpsed the highest waterfall in the world, and named it eponymously. When Angel’s plane accidentally landed on the tepui summit in 1936, Gustavo Heny, Miguel Delgado and the Angel couple discovered that the only way to descend the tepui was exactly the same that remains used today, on foot. e rst specimens from there were collected during the AMNH and William Phelps expedition in 1937 – 1938. In 1956, a Universidad Central de Venezuela expedition collected further specimens and also in stalled a Simn Bolvar statue which remains clearly visible on the summit. Roze (1958 a ) described Tropidurus bogerti (Fig. 119A) present on the summit and Neusticurus racenisi and Lio phis trebbaui on the slopes. Frogs known to inhabit the tepui summit are; Oreophrynella cryptica , Stefania shuberti, Tepuihyla edelcae, (Fig. 119F) Hypsiboas jimenezi, H. roraima, Centrolene gorzulae (Fig. 120B), Hyalinobatrachium cappellei, Pristimantis auricarens, P. marmoratus (Fig. 119C), Leptodactilus rugosus (Fig. 119D), and Anomaloglossus tepuyensis (Fig. 119B). Barrio-Amors et al. (2011) considered the recently described frog Hypsiboas angelicus Myers & Donnelly 2008 to be synonymous with H. roraima . e CLBA visit in 2007 provided precise species data t. b n b nn n Auyn Chimant Autana Roraima Sarisariama Bothrops atrox + + Crotalus durissus ruruima + Known total 35 23 6 21 20

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– Fig. 118: A – Cerro Autana (in front) and Sipapo Massif (in the background). B – The Salto Angel on Auyn Tepui. C – Surface of the meseta on Auyn Tepui. D – The aerial view of Chur Tepui from the west (Chimant Massif). E – The aerial view of Roraima from the north. F – Sinkholes (Simas) on Sarisariama.

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on Anomaloglossus tepuyensis, which commonly inhabits rapid creeks with small waterfalls. Since this species is not as agile as other small dendrobatids, they were relatively easy to capture, and Myers & Donnelly (2008) reported a wide variety of paerns amongst them. Several Pristimantis were found in the forested southern slope, and these proved quite dicult to identify. ey were initially considered to be P. pulvinatus by Myers & Donnelly (2008), but a recent work on tepui terraranans by CLBA revealed that they are P. marmoratus which inhabit the slopes of several tepuis in the Guyana Shield. CLBA party searched the summit, looking especially for the rare species Oreophrynella cryptica and Euspondylus auyanensis , but he was unsuccessful in this pursuit. ere was only the one abundant endemic species, Tropi durus bogerti , sighted during the day, and this was extremely dicult to capture because it is a very rapid mover and quickly disapears under heavy slabs. In addition, common species such as Tepuihyla edelcae (Fig. 119F) and Stefania shuberti could also be seen beneath rocks. Moreover, we herein report Norops eewi, previously Chimant endemic, from Auyn (Fig. 119E), waiting for a comprehensive taxonomic solution. Chimant Massif Chimant is a huge masi consisting of 12 dierent tepuis, all connected and biologically related. It is located between 05 05‘– 05 23‘ N, and 61 54‘– 62 15‘ W. Chimant has been one of the most explored tepui massifs in all ambits of the natural history (Huber, 1992; Gorzula, 1992). However, this extensive exploration presents no obstacle to discovering further astonish ing ndings. ese have already included the largest sandstone cave on the planet and the complex system that accompanies it (Brewer-Caras & Audy, 2011). Although its herpetofauna is well characterized, as reported by Roze (1958 b ), Gorzula (1988, 1992), Williams et al. (1996) and Barrio-Amors et al. (2010), unknown species may still exist. For example, CLBA has heard two anuran calls at the summit of Chimant which do not cor respond to any well-known species. e summit of Chimant is enormous at 1,470 km 2 and it is divided into 12 tepuis. It hides valleys, canyons and the most complex system of sandstone caves in the world (Fig. 118D). It is clear that so far we have uncovered only the very surface of its mysteries. e three com mon anuran species located on the summit of this massif are; (1) Stefania ginesi , which doesn‘t call and is quite easily found under rocks or slabs (Fig. 120C); (2) Tepuihyla edelcae , which calls around ephemeral pools aer dark, and hides under slabs and inside the tubes of bromeliad Brochinnia hechtioides during the day (Fig. 120F); and (3) Anomaloglossus rufulus (Fig. 121B) , which is an agile frog which calls during the day following rain, and inhabits shady areas in deep canyons and Bonnetia forests. In spite of this last species’s abundance and its easily heard calls throughout the entire masi, it is extremely dicult to locate and capture (Gorzula, 1988, 1992; and personal observation). Barrio-Amors & Santos (2011) re-described this species and assigned it to the correct genus, which has progressed from the original Dendrobates to Epipedobates and to Allobates, and is now correctly recognized as Anomaloglossus . Although a presence of Otophryne steyermarki has been reported at Chimant summit, unfortunately this anuran has never been heard or seen during our explorations. e most recently described species Pristim antis muchimuk (Fig. 120A) is also extremely rare, and only one specimen has ever been reported (Barrio-Amors et al., 2010). It was surprising that we could not locate some highly expected Pantepui species in Chimant, including Oreophrynella and especially some glass frogs, since there are at least three species of these frogs inhabiting neighbouring tepuis such as Auyn. e reptile most frequently found at the summit is Anadia mcdiarmidi (ex breweri sensu Kok & Rivas, 2011; Fig. 121A) which resides under slabs. Norops eewi has also been reported (but see Myers and Donnelly 2008 for its nomenclatural history) and Norops carlostoddi (Williams et al., 1996). e last taxon is apparently endemic on Chimant. One Arthrosaura is mentioned by Gorzula (1992) as undescribed, but this description is cur rently in the process of clarication by Philippe Kok and CLBA (Fig. 120D). Five snakes have been reported from the summit of the massif. e following two are apparently endemics, Atractus steyermarki and amnodynastes chimanta (Fig. 121C), while a third one, Bothriopsis taeniata lichenosa, is also possibly endemic but its relationships require further study. e remaining two occuring species Liophis trebbaui and Leptodeira annulata are more broadly distributed . e Chimant slopes have not been extensively explored, and it is almost certain that they contain a more varied herpetofauna. Only the following few species have currently been recognized there: Dendrobates leucomelas, Hypsiboas a . crepitans, H. jimen ezi, H. sibleszi, Hyalinobatrachium cappellei, H. taylori, Vitreorana helenae, Leptodactylus a. sabanensis, Rhaebo gutatus, Rhinella cf. humboldti, Norops auratus, Neusticurus rudis (Fig. 120E) , and Dipsas catesbyi. Roraima Since Roraima is more frequently visited by tourists and scien tists because of its easier accessibility by foot, it is surprising that so few studies of its herpetofauna have been made. As previously mentioned, the earliest species to be described from any tepui were from Roraima. Boulenger (1900) named four species from the slopes and two from the summit. Duellman & Hoogmoed (1984, 1992) described the following three species of frogs on the north hillside in Guyana based on collections by Adrian Warren (Warren, 1973): Stefania roraimae, Hypsiboas roraima (Fig. 121D) and Tepuihyla warreni . Surprisingly, S. roraimae and T. warreni have never been ocially reported from Venezuela. Barrio-Amors et al. (2011) commented on the distribution of H. roraima . La Marca (1996) described two dendrobatids from the slopes of Roraima: Anomaloglossus praderioi and A. roraima , while MacCulloch et al. (2007) provide an excellent account of the Roraima herpetofauna. Roraima is a paradigmatic tepui, possibly the best known, and lies between three countries, Brazil, Guyana and Venezuela at 05 12’ N, 60 44‘ W. e summit of Roraima, with a maximum altitude of 2,810 m and a surface of 34 km 2 , is small compared to that of other bigger tepuis (Autana is the only smaller one covered in this work). e slopes of Roraima are covered with a cloudy forest and countless streams. Typical Guyanese her petofauna species exist there, including Hypsiboas sibleszi, Hya linobatrachium cappellei, Anomaloglossus praderioi , Otophryne t. b n b nn n

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– Fig. 119: Species on Auyn Tepui. A – Tropidurus bogerti . B – Anomaloglossus tepuyensis. C – Pristimantis marmoratus. D – Leptodactylus rugosus. E – Norops eewi. F – Tepuihyla edelcae.

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t. b n b nn n Fig. 120: Species on Auyn and Chur Tepui: A – Pristimantis muchimuk (Chur Tepui). B – Centrolene gorzulai (Auyn). C – Stefania ginesi (Chur Tepui). D – Arthrosaura sp. (Chur Tepui). E – Neusticurus rudis (Chur Tepui). F – Tepuihyla edelcae (Chur Tepui).

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– Fig. 121: Species on Chur Tepui, Roraima and Sarisariama: A – Anadia mcdiarmidi (Chur Tepui). B – Anomaloglossus rufulus (Chur Tepui). C – Thamnodynastes chimanta (Chur Tepui). D – Hypsiboas roraima (Roraima). E – Stefania riae (Sarisariama). F – Riolama leucosticta (Roraima).

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robusta , O. steyermarki , Neusticurus rudis and Bothriopsis taeniata . However, it is on the summit where one of the most astonish ing species in the “Lost World” exists. is is the Roraima’s rough toad, Oreophrynella quelchii . Still abundant in the whole summit of Roraima, it is a terrestrial species with a small body, almost entirely black except for yellow ventral parts. It is not certain if this ventral colouration serves as defence the way yellow and black colouring does in other amphibians because Oreophrynella quelchii is best known for its defensive strategy of curling into a ball and rolling downhill to escape danger; other summit Oreophrynella , including O. nigra from Kukenn and Yuruan tepuis have also been observed to use this defensive technique. A further species of Oreophrynella , O. macconelli , exists in the base of the same tepui, and it possibly extended throughout the uplands towards Guyana. is is a rare arboreal species from the Bufonidae family. In addition, a very rarely seen species of Pristimantis is found on the summit (Barrio-Amors & McDiarmid. in prep.), and this is certainly similar to both P. yuruaniensis, described recently from the summit of Yuruan Tepui by Rdder & Jungfer (2007), and P. aureoventris from Wei-Assipu Tepui (Kok et al., 2011). Sarisariama Sarisariama is an immense tepui with maximum altitude of 2,100 m a.s.l. (Steyermark & Maguire, 1972), or 2,350 m a.s.l. (according to McDiarmid & Donnelly, 2005). However, a large part of the summit surface lies at a lower altitude. Its location is 04 30’ N, 64 14’ W, with its summit area of 546 km 2 and a slope area measuring 286 km 2 . e western part of Sarisariama was originally considered part of a larger complex known as Jaua, but now both Jaua and Sarisariama are recognized as separate tepuis. Sarisariama was initially visited by William Phelps and Julian Steyermark in a helicopter, and the rst herpetological specimen, Euspondylus phelpsi, was caught at that time (Lancini, 1968). is species, however, is currently named Cercosaura phelpsorum . While ying over Sarisariama in 1968, Charles BrewerCaras observed some immense sinkholes (simas). He lost a lot of sleep wondering about these phenomena before he organ ized a large expedition in 1974, inviting a variety of scientists to join him. ese included the botanist Julian Steyermark, and two couples, the Phelps who were ornithologist and the orquideologist Dunstervilles. ey were also accompanied by the Uruguayan herpetologist Braulio Orejas-Miranda who worked for the United States National Museum, Smithsonian Institute (USNM). Regreably, no herpetology specimens were collected from the sinkholes and no herpetological report resulted from this expedition. However, based on specimens recovered from other parts of Sarisariama during the expedition, a new species, Stefania riae, was described by Duellman & Hoogmoed (1984) (Fig. 121E). All other specimens from this expedition remain unstudied at the USNM. Four other expeditions exploring the Sarisariama simas aroused scientic interest. One in 1976 was again led by Brewer, where he acted as guide for a group of Japanese shooting a docu mentary lm, and a further one was organized in 1976 by Polish and Venezuelan speleologists (Zawidzki et al., 1976). In 1988, an RCTV crew accompanied scientists from the University Simn Bolvar to lm a documentary on the tepui and its exploration. Led by Omar Linares, they lmed and collected herps which were later studied by Barrio-Amors & BrewerCaras (2008). e most recent scientic expedition occurred in March 2002, when Brewer-Caras again organized an expedition for Japanese TV NHK. is proved to be the most important systematic col lection in Sarisariama, with 34 species reported. ese included the following ve completely new ones; Anomaloglossus moei, Hyalinobatrachium mesai, Hypsiboas tepuianus (Fig. 122B, D ), Pristimantis sarisarinama (Fig. 122C) , and Gonatodes super ciliaris (Barrio-Amors & Brewer-Caras, 2008). Ceuthomantis duellmani described by Barrio-Amors (2010) remains the most recent species published from Sarisariama (Fig. 122A). Table 13 presents species from these ve tepuis recorded above the altitudinal limit of 1,000 m. As colophon, during his 2004 overight of Aprada Tepui which lies between Auyn Tepui and Chimant, Charles Brewer landed with three helicopters in an impressive cave in the wall of the tepui. is cave was subsequenly immortalized as Cueva de El Fantasma (Fig. 13). In the few minutes that he and his companions remained inside this immense 200 metre high cave, they were able to catch frogs jumping in a puddle created by the cave’s waterfall. ese specimens were given to CLBA, who called them Colostethus (= now Anomaloglossus ) breweri in honor to the collector (Barrio-Amors, 2006). 3.4. CONCLUSIONS OF THE FAUNISTIC IN VESTIGATIONS IN THE PANTEPUI “e Lost World” or the “Islands in time” are popular terms used for the mostly inaccesible tops of the tepuis. e tepuis can also be called “Sky islands”, the term used for montane regions isolated from one another by intervening valleys with drastically dierent environmental conditions (Schultheis et al., 2012). Due to the inaccesibility of the tops of the tepuis, zoologists are still lling large gaps in a sparse mozaic of mostly unknown fauna. is is especially true for invertebrates. Despite the fact that our zoological research was only an appendix to the speleological and geological research, it has brought valuable results. In this monograph we summarize and review the results from this and previously investigated land snails, selected groups of aquatic insects and herpetofauna. Our investigations have enabled description of two new land snails from Chur Tepui; Plekocheilus (P.) vlceki and Plekocheilus (Eurytus) breweri (Breure & Schlgl, 2010). e research into aquatic insects has also proven especially fruitful. e short list of three mayy species previously recognized from the Pantepui has been substantially enlarged. Addionally, the six genera of mayies ( Baetodes, Callibaetis, Camelobaetidius, Cloeodes, Spiri tiops and Parakari ) from the family Baetidae and Massartella from the Leptophlebiidae have been reported for the rst time (Derka, 2002; Derka et al., 2009, 2012), one of them, Parakari , is the newly decribed genus (Nieto & Derka, 2011). Moreo ver, four new species ( Massartella devani , Spiritiops tepuiensis , t. b n b nn n

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Parakari auyanensis and P. churiensis ) have been descibed (Derka, 2002; Nieto & Derka, 2011, 2012), and the species Fikauneria adusta (Oligoneuriidae) was reported for the rst time from the Pantepui. Other potentially new species from the genera Mas sartella , Miroculis and Hagenulopsis remain in our collections for their formal description and publication. e entire order Plecoptera, represented by three genera Mac rogynoplax , Anacroneuria and Kempnyia, has been reported from the Pantepui for the rst time. Unfortunately, the collected nym phal material does not allow more precise identication and/or new species description. e same is partly true for Trichoptera, where the four fami lies of Calamoceratidae, Hydroptilidae, Odontoceridae and Sericostomatidae, together with the following nine genera, were recorded in the Pantepui for the rst time: Phylloicus (Calam oceratidae), Blepharopus , Macrostemum (Hydropsychidae), Orthotrichia , Oxyethira , Zumatrichia (Hydroptilidae), Oecetis , Nectopsyche (Leptoceridae) and an unidentied genus from Sericostomatidae (Derka & Zamora-Muoz, 2012). New species from various genera have also been collected, and their details will soon be published. We found a new species of unique aquatic orthopteran in habiting Cueva Charles Brewer which Derka & Fedor (2010) have already described as the new species Hydrolutos breweri, and Derka & Fedor (2012) published the description of a female from this species. It aracted the aention of the scientic com munity, and it was the Biofresh Cabinet Freshwater Curiosity in the September issue (hp://cabinetoreshwatercuriosities. com). Despite absence of typical troglobiotic adaptations in colouring and reduction of the eyes, this cave-dwelling species was observed walking and swimming in the stream of Cueva Charles Brewer in Chur Tepui plateau. Recent investigations in the Gran Sabana region and in Puerto Ayacucho region re vealed the presence of the genus Hydrolutos in lowlands below the Pantepui (Derka, unpublished data). Although it is considered an endemic of the Pantepui, and it is widespread in streams in the Guyana highlands and lowlands, it remains quite impervi ous to standard entomological and hydrobiological sampling methodology. Its elusiveness is aided by its nocturnal habits and photophobia, and resultant anity to caves, cavities and other dark well-hidden places which are dicult to access. Coleoptera from the family Elmidae were commonly sampled in the Pantepui streams. e genus Roraima was discovered and the species Roraima carinata described by Kodada & Jch (1999) from the Tun Deuta spring stream on Roraima slope. One undescribed Roraima species was sampled in the entrance of – Fig. 122: Species on Sarisariama: A – Ceuthomantis duellmani. B – Hybsiboas tepuianus (female holotype). C – Pristimantis sarisarinama . D – Hybsiboas tepuianus (male holotype).

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Cueva Charles Brewer and in various streams at Chur Tepui, and a second one in streams at Auyn Tepui. Two Jolyelmis species, J.derkai niampor & Kodada and J. reitmaieri niampor & Kodada, were discovered in a few small samples from the same stream as the Roraima carinata . Individuals of J. reitmaieri were found in Cueva de los Pmones and individuals of the new Jolyelmis species were found in various streams on Chur Tepui plateau, including those at the entrance of Cueva Charles Brewer. ese were described as J. spangleri by Kodada et al. (2012) . Finally, we reviewed and published our own data on herpeto fauna of Autana, Auyn, Chimant, Roraima and Sarisaria ma. e most recently described was the species Pristimantis muchimuk which was discovered on a speleological investigation of Chur Tepui (Barrio-Amors et al., 2010). “e Lost World”, although no longer so “lost”, continues to fascinate all its explorers. Despite having dedicated their whole lives to its exploration, many scientists consider that they have only scratched the surface of its wondrous mysteries. We are certain that there are many more creatures awaiting discovery, and we are excited by the expectation of imminent expansion of the sparse knowledge of Pantepui fauna which currently ex ists. Meanwhile, the investigations reported herein hopefully contribute to beer understanding of the origin and evolution of Pantepui fauna, and lead to eective protection of all evolu tionary treasures inhabiting the “Lost World”. ACKNOWLEDGEMENTS e research was nanced by APVV grant agency (grants No. 0251-07 and 0213-10) and VEGA Agency (grants No. 1/0246/08 and 1/0268/10). e authors are thankful to their friends who are not co-authors of this volume but took part at the expeditions for their assistance (in alphabetic order): Zoltn gh, Ren Alvarez, Ral Arias, Antonio J. Arocha, Ana Bakib, Darko Bakib, Pavol Barab, Richard Bouda, Chayo Brewer Capriles, Roberto Brewer, Luis-Alberto Carnicero, Alfredo Chacn, Leonardo Cri ollo, Robert Dado, Francisco Delascio, Igor Elorza, Marcel Grik, Viliam Guta, Ricardo Guerrero, Zdenko Hochmuth, Erik Kapucian, Frank Khazen (), Mladen Kuhta, Marin Majerk, Vicente Marcano, Peter Masarovi, Federico Mayoral, Peter Medzihradsk, Javier Mesa, Mark Moe, Peter “Becko” Ondrejovi, Jozef Ondruka, Jn Pavlk, Jaroslav Stankovi, Radko Tsler, Alberto Tovar, Ben Williams. Gustv Stibrnyi and Meander s.r.o. Tura n. Bodvou is acknowledged for providing excellent speleological equipment, as well as Gilmonte, ilina and MKB Werke Plus, Liptovsk Mikul for technical support. Comments and suggestions of the following reviewers are warmly acknowledged: ass. prof. Pavel Bella (State Nature Conservancy of the Slovak Republic, Slovak Caves Administration, Lip tovsk Mikul), prof. Anna Vozrov (Comenius University, Bratislava), prof. Juan-Ramn Vidal-Roman (University of La Corua), Ing. Marek Svitok (Technical University, Zvolen), prof. Maria Eugenia Grillet (Univer sidad Central de Venezuela, Caracas), Dr. Ross MacCulloch (Royal Ontario Museum, Toronto), prof. Maureen A. Donnely (Florida International University, Miami), Dr. Fred G. ompson (Florida Museum of Natural History, Gainesville), Dr. Timothy A. Pierce (Carnegie Museum of Natural History, Pisburgh). Language correction was made by Dr. Raymond Mar shall (Sydney, Australia), which is also warmly acknowledged. Personal acknowledgements and dedications: Roman Aubrecht dedicates his work on this book to last prof. Milan Mik, who was his former teacher. His personal thanks go to Ana and Darko Bakib, Javier Mesa, as well as to Erik Kapucian and all the members of the 2009-January expedition to Chimant, for helping him when he broke his arm. Csar Barrio-Amors would like to express his admiration to the rst tepui explorers, who unveiled many of their mysteries in times when helicopters didn’t still exist: E. Im urm, J.J. Quelch, F.V. MacConnell, Joan Mund, Flix Cardona Puig, Gustavo Heny, Jimmie Angel, Julian Steyermark. Abraham Breure is grateful to D.S.J. Groenenberg (Leiden) for assistance in the molecular laboratory and discussion of the results. L.R.L. Simone (Sao Paulo) and F.G. ompson (Gainsville) kindly provided illustra tions of taxa recently described by them. B. Hausdorf (Hamburg) supplied unpublished data that has been included in the phylogenetic analyses. Many thanks to C. Magalhaes (Manaus) for lending material from the collection in his charge. We are grateful to F.J. Borrero (Cincin nati) for discussions on the biodiversity of the Pantepui malacofauna and to A.C. van Bruggen (Leiden) for his critical review of a rst dra of this manuscript; F.G. ompson and T. Pearce reviewed the text and gave useful suggestions. Tom Derka would like to thank to Vladimr Kubovk and Barbora Klementov for their company and help in the eld during the Auyn Tepui expedition. He thanks to Marek Svitok for his company and help during various expeditions to Auyn Tepui, Roraima and other parts of t. b n b nn n

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Venezuelan Guayana and for his review of a rst dra of the manuscript. Carmen Zamora-Muoz and Jos Manuel Tierno de Figueroa from the Departamento de Zoologa, Facultad de Ciencias, Universidad de Gra nada, Spain, substantially contributed to the identication of Trichoptera and Plecoptera, respectively. Peter Fedor from the Department of Envi ronmental Ecology, Faculty of Natural Sciences, Comenius University in Bratislava collaborated in Hydrolutos identication and description. Carolina Nieto from CONICET – Instituto de Biodiversidad Neotropi cal, Facultad de Ciencias Naturales e IML, Tucumn, Argentina, greatly contributed to Baetidae (Ephemeroptera) identication and new taxa description. Natuschka M. Lee thanks to Katrin Groissmeier (biology student at TUM) and Dr. Olivier Braissant (collaborator at the university of Basel, Switzerland) for their contributions to the ongoing microbiological investigations. Branislav mda would like to express his special thanks to all his family members, especially to his girlend Bibiana Granc and to his parents, Albeta and Vladimr, for their moral support during his Venezuelan trips. Luk Vlek would like to express his thanks for material and equipment supply to the Speleoklub Tisovec of the Slovak Speleological Society and Mountain Sport Liptovsk Mikul. A special thanks is meant for whole his family supporting him in our struggles. REFERENCES Abeleedo de M.E.J., Angelelli V. & de Benyacar M.A.R., 1968: Sanjuanite, anew hydrated basic sulfateposphate of aluminum. American Mineralo gist , 53, 1-2, 1-8. Ahti T., 1992: La ora: plantas inferiores. In : Huber O. (Ed.): Chimant. Escudo de Guayana, Venezuela. Un Ensayo Ecolgico Tepuyano. Oscar Todtmann Editores, Caracas, pp. 133-138. Amdgnato Ch. & Devriese H., 2008: Global diversity of true and pygmy grasshoppers (Acridomorpha, Orthoptera) in freshwater. Hydrobiologia , 595, 535-543. 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(in Polish) mda B., Brewer-Caras Ch., Audy M., Mayoral F., Bakib D., Vlek L. & Stankovi J., 2010 a : Chur-tepui 2009 (expeditions January/February

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Zawidzki P., Urbani F. & Koisar B., 1976: Preliminary notes on the geology of the Sarisariama Plateau, Venezuela, and the origin of its caves. Boletn de la Sociedad Venezolana de Espeleologa , 7, 29-37. AUTHORS OF FIELD PHOTOGRAPHS Aubrecht, Roman: 47A,D,E,F, 49A, 53F, 55D,E,F, 69A, B, C, 96 99D Audy, Marek: 12, 19, 20, 21, 29, 52A-B, 52D, 54A, 68, 77A, 81A, 118D Barab, Pavol: 70D Barrio – Amors, Csar: 118C, 119A-F, 120B-F, 121A-F, 122A-D Brewer – Caras, Charles: title page, 8, 9, 11, 13, 15, 118 AB , EF , Derka, Tom: 7C, 48C, 71B, 116D Kapucian, Erik: 69D, 113A,D, 115E Lnczos, Tom: 7A, 7D, 41A-C, 42A-C, 43A,C,D, 45, 59E,F, 115F, 116A-C, 117B, Majerk, Marin: 27 Federico Mayoral: 104 Medzihradsk, Peter: 10, 28, 31, 32, 33, 34, 46B, 56D, Mesa, Javier: 102A, 120A Schlgl, Jn: 25, 35, 36C, 46A, 47B-C, 48A,B,D,E, 49B-D, 50A-D,F, 52C, 53A-C, 55A,C, 56E, 59B-D,G 64B,F, 69E, 70A-C, 71A,C, 73A,C-D,F, 74C-D, 76A, 77B-C, 81E, 82A-D,F-G, 83D-G, 94D, 100A, 102B, 103A,B Stankovi, Jaroslav: 14, 23, 46C-D, mda, Branislav: 36A, 43B, 48F, 49E-F,H, 51A-B, 53D, 54B, 55B-C, 56A-C-F, 64A, 73B,E, 76B, 77D-F, 81C,D, 82E, 83A-C, 100B-D Vlek, Luk: 3, 7B, 17, 18, 22, 24, 30, 49G, 50E, 53E, 59A, 59H

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– Roman Aubrecht geologist / Department of Geology and Paleontology, Faculty of Natural Sciences, Comenius University, Mlynsk dolina G, SK-842 15 Bratislava, Slovakia / Geophys ical Institute, Slovak Academy of Sciences, Dbravsk cesta 9, SK-845 28 Bratislava, Slovakia / E-mail: aubrecht@fns.uniba. sk / Co-editor of the volume; editor of the geoscientic part. Author of the chapters about speleogenesis and speleothems. Csar Luis Barrio-Amors zoologist / Instituto de Biodiversidad Tropical, Apartado Postal 220-8000, San Jos, Prez Zeledn, San Isidro del Gener al, 11901 Costa Rica / E-mail: cesarlba@ / Author of the chapter about herpetofauna. Abraham S.H. Breure zoologist / Naturalis Biodiversity Center, P.O. Box 9517, NL-2300 Leiden, the Netherlands / E-mail: ashbreure@ / Author of the chapter about gastropod fauna. Charles Brewer-Caras natural scientist / Grupo Espeleolgico de la Sociedad Venezolana de Ciencias Naturales, Caracas, Venezuela / E-mail: / Pioneer explorer of the caves on Venezuelan tepuis, discoverer of several caves, main organizer of the scientic expeditions, the results of which are summarized in this book. Tom Derka zoologist and ecologist / Department of Ecology, Faculty of Natural Sciences, Comenius University, Mlynsk dolina, SK-842 15 Bratislava, Slovakia / E-mail: / Editor of the zoo logical part of the volume. Author of the chapter about insect fauna. Milo Gregor mineralogist / Slovak National Museum, Vajanskho nbr. 2, P.O.BOX 13, 810 06 Bratislava, Slovakia / E-mail: / Main author of the parts about mineralogy of arenites and speleothems. Oswaldo Fuentes-Ramos zoologist / Calle Ibiza # 13, 5-C Fuen girola, 29640 Mlaga, Espaa / E-mail: / Co-author of the chapter about herpetofauna. Jn Kodada / zoologist / Department of Zoology, Faculty of Natural Sciences, Comenius University, Mlynsk dolina, SK-842 15 Bratislava, Slovakia / E-mail: / Contributor to the chapter about insect fauna. AUTHORS OF THE VOLUME

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ubomr Kovik / botanist / Depart ment of Botany, Faculty of Natural Sciences, Comenius University, Rvov 39, 811 02 Bratislava, Slovakia / E-mail: / Contributor to the part about microbial origin of the speleothems. Tom Lnczos hydrogeochemist / Department of Geo chemistry, Faculty of Natural Sciences, Comenius University, Mlynsk dolina-G, SK-842 15 Bratislava, Slovakia / E-mail: / Co-editor of the vol ume. Author of the chapters about climatic conditions and hydrogeochemistry and co-author of the speleogenesis chapter. Natuschka M. Lee molecular biologist and microbiologist / Department of Microbiology, Technische Universitt Mnchen, Emil-Ramann-Str. 4, 85354 Freising, Germany / E-mail: / Contributor to the part about microbial origin of the speleothems. Language and style editor of the geoscientic part. Pavel Lik engineering geologist / Geological Survey of Slovak Republic, Mlynsk dolina 1, SK817 04 Bratislava, Slovakia / E-mail: pavel. / Co-author to the part of rock hardness. Jn Schlgl g eologist and paleontologist / Depart ment of Geology and Paleontology, Faculty of Natural Sciences, Comenius University, Mlynsk dolina – G, SK-842 15 Bratislava, Slovakia / E-mail: schlogl@ / Co-editor of the volume, contributor to the chapters about speleo genesis and speleothems, as well as to the part of gastropod fauna. Branislav mda speleologist and geologist / Speleoclub of Comenius University, Department of Geology and Paleontology, Faculty of Natural Sciences, Comenius University, Mlynsk dolina G, SK-842 15 Bratislava, Slovakia / E-mail: brano.smida@gmail. com / Mapped most of the examined caves. Co-author of the chapter about speleology and contributor to the chapters about speleogenesis and speleothems. Luk Vlek speleologist and geologist / Slovak Spe leological Society, Hodova 11, SK-031 01 Liptovsk Mikul, Slovakia / E-mail: / One of the main explorers who mapped most of the exam ined caves. Author of the chapter about speleology and contributor to the chapters about speleogenesis and speleothems.


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