On the verge of extinction in Mexico today: Field observations of Ambystoma ordinarium and Ambystoma flavipiperatum with remarks on their habitat and conservation

Abstract

Mexico is a hotspot of salamander diversity and harbours 18 species of the genus Ambystoma (Amphibia: Urodela) widely distributed from the Sierra Madre Occidental to the Trans-Mexican Volcanic Belt. These species are highly threatened by various factors and some of them are considered nearly extinct in the wild. The Michoacán stream salamander, Ambystoma ordinarium and the yellow-peppered salamander, A. flavipiperatum are two endemic and scarce species from Mexico living in isolated and declining populations. Few observations have been made on them in their natural habitat since their original description. Here we report new data regarding the biology and habitats of A. ordinarium observed at Rio Bello, 2,120 m a.s.l., Morelia city, Michoacán state, and for A. flavipiperatum at Sierra de Quila, 2,165 m a.s.l., 100 km south from Guadalajara city, Jalisco state. For A. ordinarium we found one neotenic adult male and two dead adult females in a small shallow stream located within a fragmented fir, oak and pine forest. For A. flavipiperatum we recorded an adult male and a female both neotenic, one clutch of eggs, and eleven larvae inhabiting a slow-moving stream located through a riparian habitat surrounded by large pineoak forest. Our observations confirm that both species are highly endangered, capable of facultative neoteny and occur in small slow-moving streams surrounded by coniferous forests. We discuss their morphology, geographical distribution and conservation status.