Description
Adult Dermophis oaxacae are medium-sized (total lengths to 454 mm), somewhat robust caecilians with relatively large heads, subterminal mouths, and eyes that lie beneath a layer of skin. Unlike other members of the genus, they lack splenial teeth. Primary and secondary annular counts are high and nearly equal, suggesting that the species may be basal in the genus (more derived caecilians are characterized by reduction to loss of secondary annuli; several species of Dermophis have reduced numbers of secondaries).

Coloration in life is blue-black; ethanol-preserved specimens are brown-violet, with the dorsum darker than the venter (see the type description). Taylor (1968) described the color of a preserved specimen, noting that it was "generally brownish, growing somewhat violet-brown posteriorly...Ventrally the color is very light, somewhat olivebrown...the primaries and secondaries are darker on the anterior part of the annulus, lighter posteriorly...the vent area is whitish and there are vague lighter areas at tentacles and nostrils."

The species resembles D. mexicanus, with which it is sympatric, but is distinguished from it by having higher numbers of primary annuli (119 - 135 vs. 99 - 112) and secondary annuli (107 - 133 vs. 51 - 79); the number of secondary annuli is 80 - 98% that of primary annuli in D. oaxacae, in contrast to 44 - 71% in D. mexicanus. The tentacle is somewhat closer to the eye than to the nostril compared with D. mexicanus (but these measurements apparently vary with age). The species is somewhat smaller than D. mexicanus, reaching a maximum reported total length of 454 mm, in contrast to the 600 mm of D. mexicanus.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Mexico

View distribution map in BerkeleyMapper.

Dermophis oaxacae is endemic to México, occurring in Jalisco, Michoacán, Guerrero, Oaxaca, and Chiapas (Alvarez and Martin 1967, Casas-Andreu et al.1996, Dunn 1942, Erwin 1973, Lafrentz 1928, Mertens 1930, Savage and Wake 1972, Smith and Taylor 1948, 1938, Taylor and Smith 1945). Their habitats range from sea level to 2100 m, the latter in Michoacán. Animals have been found primarily associated with cultivated (agricultural) areas once dominated by tropical deciduous forest, tropical scrub, and tropical evergreen forest, but also in those habitats and in pine-oak forest. In Oaxaca, the species occurs in the lowlands of the Sierra Madre del Sur and the Planicie Costera del Pacifico (Casas-Andreu et al. 1996), so vegetation is of low stature and is xerophyllic. Lafrentz (1928) reported that the type specimen was collected from the "dungheap of the mule stable", and that the common name is "metlapil."

Life History, Abundance, Activity, and Special Behaviors
Little is known about the natural history of Dermophis oaxacae. Its dietary habits and other aspects of its ecology and life history are inferred to be similar to those of the closely related D. mexicanus (see Wake 1980 and Wake 1983).

Dermophis mexicanus is a terrestrial burrower, is live bearing and has a long gestation period of about a year (Wake 1980).

Trends and Threats
The species is known form only approximately 30 specimens, and apparently has not been collected anywhere in Mexico since 1972 (Wake 1998). An effort must be made to locate any remaining populations and to establish a monitoring and conservation program (Wake 1998).

Possible reasons for amphibian decline

General habitat alteration and loss
Intensified agriculture or grazing

Comments

References

Alvarez, T. and Martin, E. (1967). ''Zitacuaro, Michoacan, una localidad mas nortena para Dermophis multiplicatus oaxacae (Amphibia: Caeciliidae).'' Acta Zoologica Mexicana, 9(2), 1-4.

Casas-Andreu, G., Mendez-de la Cruz, F.R., and Camarillo, J.L. (1996). ''Anfibios y reptiles de Oaxaca. Lista, distribucion y conservacion.'' Acta Zoologica Mexicana, 69, 1-35.

Dunn, E. R. (1942). ''The American caecilians.'' Bulletin of the Museum of Comparative Zoology, 91(6), 439-540.

Erwin, D.B. (1973). ''Dermophis oaxacae (Oaxacan Caecilian).'' HISS NewsJournal, 1, 98.

Lafrentz, K. (1928). ''Reisebrefe aus Mexiko.'' Blätter für Aquarien und Terrarienkunde, 39, 115-116.

Mertens, H. (1930). ''Bemerkungen über die von Herrn Dr. K. Lafrentz in Mexiko gesammelten Amphibien und Reptilien.'' Abhandlungen und Berichte des Museums für Naturkunde, Heimatk. Vorg. Magdeburg, 6, 153-155.

Savage, J.M. and Wake, M.H. (1972). ''Geographic variation and systematics of the Middle American caecilians, genera Dermophis and Gymnophis.'' Copeia, 1972(4), 680-695.

Smith, H.M. and Taylor, E.H. (1948). ''An annotated checklist and key to the Amphibia of Mexico.'' United States National Museum Bulletin, 194, iv + 118.

Taylor, E.H. (1938). "Concerning Mexican salamanders." University of Kansas Scientific Bulletin, 25, 259-312.

Taylor, E.H. (1968). The Caecilians of the World. A Taxonomic Review. University of Kansas Press, Lawrence, Kansas.

Taylor, E.H. and Smith, H.M. (1945). ''Summary of the collections of amphibians made in Mexico under the Walter Rathbone Bacon Traveling Scholarship.'' Proceedings of the U.S. National Museum, 95, 521-613.

Wake, M. H. (1998). ''Dermophis oaxacae (Mertens).'' Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles, 661.1-661.2.

Wake, M.H. (1980). "Reproduction, growth, and population structure of the Central American caecilian Dermophis mexicanus (Amphibia: Gymnophiona)." Herpetologica, 36, 244-256.

Wake, M.H. (1983). ''Gymnopis multiplicata, Dermophis mexicanus, and Dermophis parviceps(soldas, suelda con suelda, dos cabezas, caecilians).'' Costa Rican Natural History, D. H. Janzen, eds., University of Chicago Press, Chicago, Illinois, 400-401.

Species Account Citation: AmphibiaWeb 2024 Dermophis oaxacae: Oaxacan Caecilian <https://amphibiaweb.org/species/1878> University of California, Berkeley, CA, USA. Accessed Nov 6, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 6 Nov 2024.

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