Range extension of the endangered rodent Rhipidomys tribei (Cricetidae: Sigmodontinae) in Southeastern Brazil

ABSTRACT The arboreal rodent Rhipidomys tribei Costa, Geise, Pereira & Costa, 2011, which is endemic to Southeast Brazil, is a sparsely documented species, with only five confirmed published records, mainly in the mountainous areas of the Atlantic Forest and the transitional semi-deciduous zones adjacent to the Cerrado biome. We report a new locality for R. tribei within the Itatiaia National Park, in the municipality of Itatiaia, state of Rio de Janeiro, Brazil, within the Mantiqueira Mountains range, where we captured six individuals. This discovery significantly expands the known geographic range of this rare and endangered species. Taxonomic identification was confirmed by cytogenetic and mitochondrial cytochrome b gene analyses. Our results support the Meridional Mantiqueira Mountains as a new habitat for R. tribei, extending its range approximately 300 km southward into Rio de Janeiro. This identification is significant because R. tribei remains unrecorded in the neighboring lowlands and Serra do Mar Mountains, where its sister species, Rhipidomys itoan Costa, Geise, Pereira & Costa, 2011, is found.