Diversidade de espécies, variação cariotípica e distribuição dos roedores da Chapada Diamantina, BA

Abstract

The Chapada Diamantina is a vast mountainous plateau in the interior of Bahia state, with altitudes varying from 400 to 2000m. No systematic mammal survey encompassing the total latitudinal and altitudinal ranges of the Chapada Diamantina was attempted so far. Six expeditions were performed in to a total of 18 different sampling localities, between December/2002 and February/2004. Specimens were captured in Sherman and pit-fall traps, karyotyped and prepared as vouchers deposited in the Museu Nacional, Rio de Janeiro. In addition, specimens previously deposited in mammal's collection in Museu Nacional were also analyzed. A total of 19 species of rodents was registered and 12 of them are new registers for the area. All species were characterized on the basis of cranial morphology and pelage coloration. Karyological studies were performed to 14 species but the diploid and fundamental numbers were given to 18 species recorded. The 19 species can be separated in three main groups. a more widespread one, proper of caatinga and agreste habitats, a second one, composed mainly by forms from more densely forested landscapes, and the third group, which usually occurs in altitudinal fields in the rocky outcrops of higher limits of the Chapada Diamantina. A pattern of latitudinal diversity was also observed. Five of the 19 species registered occurs only above 1000m. The Serra do Sincorá (central region) and Morro do Chapéu (north region) presented the most diverse rodents fauna, considering the specimens collected in our surveys. In addition with the species previously deposited in Museu Nacional, the Serra do Sincorá region is the most diverse. Therefore, three areas were considered as potentially areas for preservation in Chapada Diamantina: Mucugê and Palmeiras located in Serra do Sincorá and Morro do Chapéu.