Amphibians and Reptiles of Mexico: Diversity and Conservation

Abstract

The amphibian clade in Mexico consists of 411 species: 250 frogs, 158 salamanders, and 3 caecilians. Reptiles are composed of 1073 species: 58 turtles, 572 lizards, 439 snakes, and 4 crocodiles. Worldwide, Mexico occupies the fifth and second position of species richness of amphibians and reptiles, respectively. Additionally, the level of endemism is markedly high, with 69.8% of the amphibian and 52% of the reptile species occurring only in Mexico. Of the endemic amphibian species, 152 are frogs, 134 are salamanders, and one is a caecilian, whereas for reptiles, 19 are turtles, 297 are lizards, and 242 are snakes. The most speciose Mexican frog families are Hylidae (103 species, 40.1%), Craugastoridae (36 species, 14.1%), Bufonidae and Eleutherodactylidae (34 species each, 13.5%), and Ranidae (27 species, 10.7%). The 158 species of salamanders occurring in Mexico rank this country as the second highest in caudates species diversity (84.8%). Six genera of plethodontid salamanders are endemic to Mexico: Aquiloeurycea, Chiropterotrition, Isthmura, Ixalotrition, Parvimolge, and Thorius. The Mexican species of reptiles are distributed in 40 families (43.9% of the 91 world reptile families). Phrynosomatidae is the most diverse lizard family (26.7% of Mexican lizard species), for snakes is Colubridae (72.7% of Mexican snake species), for crocodiles, the two families (Crocodylidae and Alligatoridae) share two species each, whereas for turtles the most diverse family is Kinosternidae (35% of 58 Mexican turtle species). Mexican amphibians are more threatened than other vertebrate groups with 50% of its species at global risk in comparison with birds (5%), mammals (19%) or reptiles (14%). The Mexican frog families with highest proportion of threatened species are Hylidae (53.4%), Craugastoridae (44.4%), Ranidae (37%), Eleutherodactylidae (32.4%), and Bufonidae (29.4%). Two of the four Mexican salamander families present high levels of species at global risk, Plethodontidae (84.1%) and Ambystomatidae (58.8%). Of the 17 species of Ambystoma, 10 (58.8%) are at global risk and 16 (94.1%) species are endemic to Mexico. Some of these species, such as A. mexicanum of Xochimilco Lake and A. dumerilii in Patzcuaro Lake are emblematic of the Mexican culture and of the Mexican fauna. Among reptiles, turtles are the most endangered group in Mexico, with 29% of species at global risk. Chelonia, Eretmochelys, Caretta, Dermatemys, Dermochelys, and Lepidochelys are the turtle genera with 100% of their species at risk. Of 569 species of lizards registered in Mexico, 57 (10%) are at global risk. Anguidae stands out as a speciose lizard Mexican family (50 species) with high endemicity (80%) and 30% of species at risk. The lizard genera with higher proportion of species at risk are Sauromalus (60%), Uta (57%), Ophisaurus (50%), Ctenosaura (40%), Abronia (38%), and Barisia (29%). Of the 439 snake species in Mexico, 27 (6.2%) are at global risk. Viperidae stands out as a speciose snake family in Mexico (76 species) with high endemicity (56.6%) and with 10.5% of its species at risk. The snake genera with high proportion of species at global risk in Mexico are Botriechis and Mixcoatlus (50% each), Adelophis (50%), and Storeria (33.3%). The main threats facing amphibians and reptiles in Mexico are habitat loss and degradation, environmental pollution, unsustainable use, introduced invasive species, emergent diseases, and global climate change.