AMPHIBIAWEB
Eurycea spelaea
Grotto Salamander, Ozark Blind Cave Salamander
Subgenus: Typhlotriton
family: Plethodontidae
subfamily: Hemidactyliinae

© 2006 Michael Graziano (1 of 20)

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Conservation Status (definitions)
IUCN (Red List) Status Least Concern (LC)
See IUCN account.
NatureServe Status Use NatureServe Explorer to see status.
CITES No CITES Listing
Other International Status None
National Status None
Regional Status None

   

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Description
A cave-dwelling salamander. This is the only known blind, troglobitic salamander which undergoes a complete metamorphosis. Adults are white, pinkish white, or light brown on the dorsum and venter. The reduced eyes are dark spots visible through the partially fused eyelids. Adults are 36-70 mm snouth to vent length (75-135 mm total length) with 16-19 costal grooves. Sexually mature males have a slightly swollen upper lip and a pair of cirri (papilla-like extensions from the upper lip). Like many other plethodontid salmanders, males also have a mental gland, a raised area on the chin used in courtship. Hatchlings are 13 mm snout to vent length (17 mm total length). The larvae have bushy gills and a moderately high dorsal tail fin. Larvae are lightly pigmented (tan dorsally, often weakly stippled or mottled) and have functional eyes. The eyes become atrophied and the eyelids fuse at metamorphosis (Brandon 1970; 1971; Petranka 1998; Besharse and Brandon 2005).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: United States

U.S. state distribution from AmphibiaWeb's database: Kansas, Missouri

View distribution map using BerkeleyMapper.
Restricted to two plateaus in the Ozark region of southern Missouri, extreme southeastern Kansas, and adjacent areas in Arkansas and Oklahoma. Missouri distributions in 25 counties were mapped by Johnson (2000). Adults are not known outside of the twilight and dark zones of caves and sinkholes, but larvae are found in cave entrances and springs as well as nearby creeks. Adults may be found in water or on moist vertical rock walls which extend out of the water. Sandy or gravelly substrates are preferred by the larvae (Hendricks and Kezer 1958; Brandon 1970, 1971; Petranka 1998; Trauth et al. 2004).

Life History, Abundance, Activity, and Special Behaviors
Courtship has not been described. Mating occurs from late spring through summer. Oviposition likely occurs from late summer to fall when females disapper from the surface. Oviposition sites have not been documented, but presumably are in rocky crevices. Female attendance of eggs is likely. Clutch size from one female was 13 (Brandon 1971; Petranka 1998). The larval period lasts from 1-3 years (Brandon 1971).

Grotto salamanders are most active during spring and summer months when moisture levels in caves are high, food is abundant, and courtship is taking place. Adults feed on aquatic and terrestrial invertebrates, including flies, mosquito larvae and beetles. Adults may function as a top predator in some cave systems. Predators have not been reported although larvae are likely to be vulnerable to crayfish (Brandon 1971; Petranka 1998).

The grotto salamander is most abundant in caves that harbor high numbers of bats (Hendricks and Kezer 1958; Bonett and Chippindale 2004; Brandon 1971). From late April to October, and particularly during the summer, gray bats (Myotis grisescens) make use of caves as maternity roosts (Hendricks and Kezer 1958; Bonett and Chippindale 2004; Brandon 1971). Bats deposit feces (guano) within the cave, leading to an increase in invertebrates associated with the guano. Grotto salamander larvae eat isopods, fly larvae, and snails (Brandon 1971; Petranka 1998), but in a highly unusual move for animals that are normally thought of as strictly carnivorous, grotto salamander larvae also consume bat guano (Fenolio et al. 2006). Bat guano is a source of high nutrition in a resource-poor environment (the cave) since bats have short digestive tracts and fast digestion times and do not extract the full nutritive value of food items. Guano has been found to contain twice the protein content and about two-thirds the calories of an equivalent volume of Big Mac hamburger (Fenolio et al. 2006). Microbial biofilms on the guano may provide extra nutritive value (Fenolio et al. 2006). The nutritive value of guano was found to be higher in terms of protein content, caloric density, and essential mineral content than a potential prey item, cave-dwelling gammarid amphipods (Fenolio et al. 2006).

Multiple species of helminth parasites (protozoans, trematodes, cestoids, nematodes, acanthocephalans) infecting E. spelaea have been noted (Dyer 1975; McAllister et al. 2006).

Trends and Threats
Caves represent a fragile ecosystem vulnerable to disturbance and pollution. Long-term monitoring will be needed to determine population trends of these animals (Petranka 1998). This species occurs within several protected areas, but local threats include degradation of ground water quality; forest clear-cutting is also a threat, as this can affect bat populations (Hammerson 2004).

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities
Drainage of habitat
Subtle changes to necessary specialized habitat
Local pesticides, fertilizers, and pollutants

Comments
First described by Stejneger (1892). This species is unique in that it starts life as a fully sighted larva but then metamorphoses underground into a terrestrial adult that loses its pigment and becomes blind, with the eyelids eventually fusing. Recent molecular studies have shown that it is a close relative of species of the genus Eurycea that occur nearby. It differs strikingly from these species in its larger size and cave-related features, but because it is phylogenetically nested within the Euryea multiplicata complex, Bonett and Chippindale placed it in Eurycea. In an alternative to Linnean classification, the name Typhlotriton could be retained as a clade name, for example in Phylocode. Because mitochondrial DNA sequence divergence within E. spelaea is relatively great, some of the populations might be recognized as distinct species (two additional species were described in the past but now included within E. spelaea).

References
 

Besharse, J. C., and Brandon, R. A. (2005). ''Postembryonic eye degeneration in the troglobitic salamander Typhlotriton spelaeus.'' Journal of Morphology, 144(381-405).  

Bonett, R., and Chippindale, P. T. (2004). ''Speciation, phylogeography, and evolution of life history and morphology in plethodontid salamanders of the Eurycea multiplicata complex.'' Molecular Ecology, 13(5).  

Brandon, R. A. (1970). ''Typhlotriton and T. spelaeus.'' Catalogue of American Amphibians and Reptiles. American Society of Ichthyologists and Herpetologists, 84.1-84.2.  

Brandon, R. A. (1971). ''Correlation of seasonal abundance with feeding and reproductive activity in the Grotto Salamander (Typhlotriton spelaeus).'' American Midland Naturalist, 86(1), 93-100.  

Dyer, W. G. (1975). ''Parasitism as an indicator of food sources in a cave-adapted salamander habitat.'' Bulletin of the Southern California Academy of Sciences, 74, 72-75.  

Fenolio, D. B., Graening, G. O., Collier, B. A., and Stout, J. F. (2006). ''Coprophagy in a cave-adapted salamander; the importance of bat guano examined through nutritional and stable isotope analyses.'' Proceedings of the Royal Society B, 273, 439-443.  

Hendricks, L. J., and Kezer, J. (1958). ''An unusual population of a blind cave salamander and its fluctuation during one year.'' Herpetologica, 14(1), 41-43.  

Johnson, T.R. (2000). Amphibians and Reptiles of Missouri: 2nd Edition. Conservation Commission of Missouri, Jefferson City.  

McAllister, C. T., Bursey, C. R., Trauth, S. E., and Fenolio, D. B. (2006). ''Helminth parasites of the grotto salamander, Eurycea spelaea (Caudata: Plethodontidae), from northern Arkansas and southern Missouri, U.S.A.'' Comparative Parasitology, 73, 291-297.  

Petranka, J. W. (1998). Salamanders of the United States and Canada. Smithsonian Institution Press, Washington and London.  

Stejneger, L. (1892). ''Preliminary description of a new genus and species of blind cave salamander from North America.'' Proceedings of the United States National Museum, 15, 115-117.  

Trauth, S. E., Robison, H. W., and Plummer, M. V. (2004). The Amphibians and Reptiles of Arkansas. The University of Arkansas Press, Fayetteville, Arkansas.



Written by Meredith J. Mahoney, additions by David B. Wake and K. Whittaker (molge AT yahoo.com), Museum of Vertebrate Zoology, UC Berkeley
First submitted 2004-03-20
Edited by Kellie Whittaker (2010-12-30)



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Citation: AmphibiaWeb: Information on amphibian biology and conservation. [web application]. 2014. Berkeley, California: AmphibiaWeb. Available: http://amphibiaweb.org/. (Accessed: Dec 17, 2014).

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