Abstract
The mid-Araguaia River basin in central Brazil is considered a priority area for biodiversity conservation, and Parque Es-tadual do Cantao (PEC) is one of the most important protected areas in this ecotone between Cerrado and Amazonia. This area suffers an intensive human pressure with high rates of deforestation, and still remains poorly studied in terms of biodiversity. From June 2007 to November 2008 we sampled small mammals from both banks of the mid-Araguaia River, in the states of Tocantins andPara. Data are given about morphological traits, geographic distribution and natural history of 22 species of small non-volant mammals (eight marsupials and 14 rodents) surveyed at PEC and its surroundings. We also present mitochondrial phylogenetic analyses that allow species identification within the genera: Oecomys, Oligory-zomys and Rhipidomys, and delineate an undescribed species of Thrichomys. Based on morphologic and molecular data, we describe a new species of Rhipidomys previously assigned toR. nitela, which is apparently endemic to the Araguaia-Tocantins basin in the Cerrado. Additionally, our phylogenetic analyses provide support for the role played by the Ara-guaia River as an important geographic barrier for two sister species of Rhipidomys.
NSTL