Oaxacan Caecilian

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. Unlikeother 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.The species is named for the Mexican state, Oaxaca, in which the type specimen was collected.

D. 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); Taylor, (1938); Taylor and Smith, (1945)). 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."

Little is known about the natural history of Dermophis oaxacae. Its dietary habits and other aspects of its ecology and life history are inferred tobe similar to those of the closely related D. mexicanus (see Wake (1980)and Wake (1983)). D. mexicanus is a terrestrial burrower, is live bearing and has a long gestation period of about a year (Wake 1980).

The species is known form only approximately 30 specimens, and apparentlyhas not been collected anywhere in Mexico since 1972(Wake 1998). An effort must bemade to locate any remaining populations and to establish a monitoringand conservation program (Wake 1998).