271 Cerrophidion tzotzilorum (Campbell, 1985). The Tzotzil Montane Pitviper is endemic to Chiapas, where it is restricted to humid pine oak forest in the Central Plateau physiographic region at elevations from 2,050 to 2,500 m. Its EVS has been established at 19, placing it in the upper portion of the high vulnerability category; this value is the highest for any herpetofaunal species in the state. Interestingly enough, this species has been allocated as Least Concern by the IUCN, but is considered a species of special protection by SEMARNAT. This pitviper is part of a clade of five snake species distributed in the highlands of Mesoamerica from west central Veracruz, Mexico, to central Costa Rica. Its sister species appears to be C. petlalcalensis, the most northerly occurring member of the clade. This individual was found in the vicinity of San Cristóbal de las Casas, in the municipality of San Cristóbal de las Casas, and was photographed at the Zoológico Regional Miguel Álvarez del Toro. ' © Elí García Padilla, courtesy of Antonio Ramírez-Velázquez 271