Snakes from a transitional area between Cerrado and Atlantic Forest in southeastern Brazil

Abstract

The snakes fauna composition of the municipalities of Ouro Preto, Mariana, and Itabirito, in Minas Gerais, Brazil, was studied. The study area is located on the southern region of the Espinhaço Mountain Range, presenting an altitude tropical climate, and the vegetation is characterized as an ecotone between Cerrado and Atlantic Forest biomes. A survey of snakes was carried out between the period of june 2000 and May 2003 using direct encounters plus 12 fixed collecting stations, collections museum voucher analyses, and literature. A total of 58 species were recorded belonging to 32 genera of the families Colubridae (50 species), Viperidae (4), Elapidae (2), Tropidophiidae (1), and Leptotyphlopidae (1). Thirty- seven species were collected during this study, 20 were registered only as museum voucher, and just one in literature. Some species presented morphological variations or uncertain taxonomic status. The study area presented high snake species richness, placed among the five richest areas of Brazil. The studied fauna revealed more similar to other Cerrado areas as it is composed by 43 species reported for Cerrado, 39 for Atlantic Forest, and 24 for both biomes. Two hundred and ten specimens were collected, of which Bothrops neuwiedi presenting the highest encouter frequency (14.29%). Seven species and a genus had a known geographic distribution significantly extended. The conservation status of ten species precludes a better evaluation as some of them might represent isolated populations. Most of the species were recorded from local conservation units. We also provide an identification key for the snakes recorded in the study area.