29 Observation of the Catfish Chaetostoma microps Climbing in a Cave in Tena, Ecuador Georey Hoese 1 Aaron Addison 2 eolos Toulkeridis 3,4 Rickard Toomey III 5 1 Texas Speleological Survey, 2605 Stratford Drive, Austin, Texas, USA 2 Washington University in St. Louis CB, 169, St. Louis, MO, USA 3 Universidad de las Fuerzas Armadas ESPE, Sangolqu, Ecuador 4 Centro Panamericano de Estudios e Investigaciones Geogrcas (CEPEIGE), Quito, Ecuador 5 Mammoth Cave Inter national Center for Science and Learning Mammoth Cave National Park, USA Corresponding author: Georey Hoese ( firstname.lastname@example.org ) Academic editor: O. Moldovan |Received 2 March 2015|Accepted 11 April 2015|Published 16 April 2015 http://zoobank.org/94F70D72-E11D-4FC1-858D-8311F5F1007E Citation: Hoese G, Addison A, Toulkeridis T, Toomey R III (2015) Observation of the Catsh Chaetostoma microps Climbing in a Cave in Tena, Ecuador. Subterranean Biology 15: 29. doi: 10.3897/subtbiol.15.4809 Abstract As part of a mapping and preliminary ora and fauna inventory of hypogean life in caves, developed in Cretaceous limestones in the sub-andean zone of Ecuador, we were able to observe a number of catsh climbing a steep owstone waterfall in the dark zone of a cave. e waterfall was a minor infeeder to the small stream that owed through the cave. On investigation the sh were determined to be Chaetostoma microps Gnther, 1864 (Siluriformes Loricariidae), a detritivorousherbivorous neotropical freshwater catsh, endemic to the upper reaches of the Amazon basin in Ecuador. We document the observation of this species exhibiting climbing behavior as well as the rst observation of the family exhibiting climbing behavior in a cave. We also document the sympatry of this species and Astroblepus pholeter Collette, 1962 (Siluriformes Astroblepidae). Keywords Catsh, Karstic caves, Ecuador Subterranean Biology 15: 29 (2015) doi: 10.3897/subtbiol.15.4809 http://subtbiol.pensoft.net Copyright Geoffrey Hoese et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0) which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. RESEARCH ARTICLE Subterranean Biology Published by The International Society for Subterranean Biology A peer-reviewed open-access journal
30 Observations Mapping and documenting caves was conducted in the vicinity of Tena, Napo Dis trict, Ecuador. Our team visited a number of caves, of which several had sucient inow through subterranean infeeders to maintain small amounts of stream ow, with occasional larger pools of standing or slowly owing water. A number of scattered indi vidual sh of three distinct types were observed. Two small (3 cm) catsh were seen, one with little to no obvious pigment and very reduced eyes, and another of similar size, but pigmented and with normal eyes. In two larger pools we also had very brief observations of a generally fusiform, highly reective sh estimated to be from 5 cm in size. ese last observations were very brief and insucient for any attempt at identication. As we had no permit and were not equipped for collection, we did not capture any sh from the streams or pools. e unpigmented catsh were taken out of the water and we were able to make close observation as well as to take some photo graphs of them. Based on the general appearance we determine them to be Astroblepus pholeter Collette, 1962. e pigmented catsh were more skittish, and we were unable to make any close observations. In a later cave however, we were quite surprised to nd them in a context that allowed for more detailed observation, climbing out of the stream in a relatively small amount of owing water originating higher in the cave wall. e sh were observed climbing a owstone waterfall originating in an area of two to three irregularly shaped openings on the east side of the main passage about 3 meters above the stream level in the main passage. ese openings are of approximately 40 cm wide and 10 cm high with water owing through the lower third or less, owing from a small pool 5 cm deep that cannot be accessed or observed for more than one meter. Total ow was estimated to be in the range of 5 liters per second, which spread pri marily in sheet ow of 0.5.5 cm thick down a owstone formation about 1.5 meters, to a ledge with small pools with a total area of about 1 square meter. is continued down a the lower, larger portion of owstone in sheet ow, continuing for approximately another 1.5 meters to stream level. Slope on the owstone sections ranged from slightly overhung to horizontal, with a least sloping path requiring signicant sections of 70 degree slope to be traversed, and the more direct path having near vertical sections (Fig. 1). Two individuals were observed on the lower part, above a near vertical section of the owstone about 1 meter above the stream, and three individuals were on the upper part within 10 cm from the inow source on a near vertical section. One of the in dividuals on the lower section quickly spooked and dropped o the wall into the water below. Photographs and video were acquired of the second lower individual, which re acted to our presence and made a number of movements across the owstone, primar ily horizontal with some loss of elevation (Fig. 2). A video of the movement of the sh across the owstone may be seen at http://www.youtube.com/watch?v=YyzPZfCbC-s We attempted to capture this individual for identication, but lacking nets the at tempt by hand was unsuccessful. Subsequently one of the individuals near the top of the owstone was captured using a glove. It was photographed (Fig. 3) and released alive and in good condition in the pool.
31 Discussion Loricariids and other sh have been known to climb rocks and waterfalls on surface streams and signicant research has been undertaken on this behavior (Schoenfuss 2003, Blob and Rivera 2008, Blob et al. 2010). Climbing behavior is known from epigean astroblepids and loricariids (Schaefer 2003, Schaefer and Provenzano 2008) Although this observation is of a single location in one cave, it seems a reasonable ex trapolation that it is not an unusual event for the species of these taxa to climb both in surface streams and in other caves. Studies have been done of the anatomical characters loricariids use to climb (Geer inckx et al. 2007) as well as respiratory adaptations that may allow them access in the high levels of carbon dioxide and low oxygen that may be present in cave waters (Brauner et al. 1995, Armbruster 1998, MacCormack et al. 2003, Proudlove 2006). Although these studies provide a basis for speculation, the actual motivation for a given catsh to climb in the cave may be harder to assess. e inow observed was unlikely to have originated from a surface stream. It seems reasonable to assume that it originates from percolating meteoric water, accumulating in a series of larger voids until sucient ow is established to maintain a continuous stream. e interest of the catsh in reaching the headwaters of this ow is unclear. e more obvious possibil ity would be that they merely occupy the physical limits of the range they are capable of reaching, and that the extension of this into caves is coincidental. is suggestion can be extended to include otherwise unrelated behavior, such as spawning, that may provide additional impetus to head upstream. As Chaetostoma have been shown to be Figure 1. Map of Cave showing location of observation (arrows) of the catsh. Location of cave is some 8.3 km east of Tena city, close to the community Guayusa Loma.
32 Figure 2. Chaetostoma microps in situ on owstone wall in sheet ow. Note that the sh is facing up. e slope at this location is estimated to be approximately 75 degrees. more algivorous (Lujan et al. 2012) it seems unlikely that they inhabit the caves for extensive periods. However, owstone features and rocks in cave streams may host microbial lms that could be grazed, providing some nutrition. We would be remiss not to consider that unrecognized benets may have provided selection pressure as an agent in the adaption of caves into their range. ere are a
33 number of possible suggestions, all of which are speculative. In the case of spawning, cave adapted Astyanax mexicana has been shown to be sensitive to water temperature induced spawning (Borowski 2008). However, other climbing shes are known to spawn in the ocean and return to fresh water streams as adults (Fukui 1979, Kin zie 1988). Greater dispersal to small pools in the upper reaches of cave systems may increase survivability in drought conditions. Predators may also be avoided by this behavior, as has been suggested for other taxa (Blob et al. 2010). It does seem reason able to assume that a fair number of the infeeders of the broader river basin where this species is resident have their origins in springs that ow from a number of caves. A correlation of this range to the extent of the geologic range of the karstic members in the area may provide some insight, although insucient data exists at present to make any determinations. In any event, it is clear that further study is needed to understand this behavior. Acknowledgments We would like to thank Dr. Nathan Lujan with the Academy of Natural Sciences of Drexel University and Dr. Jonathan Armbruster with the University of Auburn Figure 3. Chaetostoma microps, lateral view
34 for their assistance with the identication of the sh. Dr. H.D. Hoese of Rockport Texas, and Dr. Douglass Hoese of e Australian Museum provided additional useful references. We thank the anonymous reviewers for suggestions and comments that improved the manuscript. A special acknowledgement goes to the editorial handling of Dr. Oana Moldovan. We would also like to thank our guide, Jose Raul Grefa, and the people of Napo District who graciously allowed us to access their lands and caves. References Armbruster JW (1998) Modications of the digestive tract for holding air in loricariid and scoloplacid catshes. Copeia 1998: 663. doi: 10.2307/1447796 Blob RW, Rivera G (2008) Going with the ow: ecomorphological variation across aquatic ow regimes: an introduction to the symposium. Integr. Comp. Biol. 48(6): 699. doi: 10.1093/icb/icn093 Blob RW, Kawano SM, Moody KN, Bridges WC, Maie T, Ptacek MB, Julius ML, Schoenfuss HL (2010) Morphological selection and the evaluation of potential tradeos between escape from predators and the climbing of waterfalls in the Hawaiian stream goby Sicyopterus stimpsoni Integr. Comp. Biol. 50: 1185. doi: 10.1093/icb/icq070 Borowski R (2008) Breeding Astyanax mexicanus through Natural Spawning. CSH Protoc. pdb.prot5091. doi: 10.1101/pdb.prot5091 Brauner CJ, Ballantyne CL, Randall DJ, Val Al (1995) Air breathing in the armoured catsh ( Hoplosternum littorale ) as an adaptation to hypoxic, acidic, and hydrogen sulphide rich waters. Canadian Journal of Zoology 73(4): 739. doi: 10.1139/z95-086 Collette Bruce B (1962) Astroblepus pholeter a new species of cave-dwelling catsh from eastern Ecuador. Proceedings of the Biological Society of Washington 75: 311314. Fukui S (1979) On the rock-climbing behaviour of the goby, Sicyopterus japonicus Jpn. J. Ichthyol. 26: 84. Geerinckx T, Brunain M, Herrel A, Aerts P, Adriaens D (2007) A head with a suckermouth: a functional-morphological study of the head of the suckermouth armoured catsh Ancistrus cf. triradiatus (Loricariidae, Siluriformes). Belg. J. Zool. 137(1) : 47. Gnther A (1864) Catalogue of the Fishes in the British Museum, vol. 5. Catalogue of the Physostomi, Containing the Families Siluridae, Characinidae, Haplochitonidae, Sternoptychidae, Scopelidae, Stomiatidae in the Collection of the British Museum. Trustees, London, xxii + 455 pp. Kinzie RA III (1988) Habitat utilization by Hawaiian stream shes with reference to commu nity structure in oceanic island streams. Environ. Biol. Fishes 22: 179192. doi: 10.1007/ BF00005380 Lujan NK, Winemiller KO, Armbruster JW (2012) Cryptic trophic radiation within a hyper diverse catsh lineage. BMC Evolutionary Biology 12(124):1. Romero A, Paulson KM (2001) Its a wonderful hypogean life: a guide to the troglomorphic shes of the world. Developments in environmental biology of shes 21: 13.
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