Taxonomic and conservation status of the elusive Oecomys cleberi (Rodentia, Sigmodontinae) from central Brazil

The arboreal mouse Oecomys cleberi was described in 1981 based on just one specimen from Distrito Federal in central Brazil, and it has not been recorded ever since. Its taxonomic status as a valid species has been questioned and it is currently listed as Data Deficient in terms of conservation status. Here we used ancient DNA methods to obtain a partial mitochondrial cytochrome b gene sequence from the holotype of Oecomys cleberi. Very low levels of genetic divergence (0.6% on average) allowed us to associate sequences from specimens previously identified as O. bicolor to O. cleberi. Comparative analyses of morphological and molecular data confirmed the taxonomic status of O. cleberi as a valid species, and increased our knowledge on its geographic distribution to at least three additional localities in the Cerrado of central Brazil. Cytochrome b sequences of O. cleberi formed a well-supported monophyletic group and diverged 6.8% on average from those of O. bicolor, its sister species from the Amazon. We refined and improved the morphological description of O. cleberi based on the examination of 15 museum specimens, including the holotype, and suggest that other field and museum records of this species may have also been misidentified as O. bicolor. Considering that O. cleberi may be more common and widespread than previously suspected, we suggest the conservation status of Least Concern for this species. However, further studies are needed to understand population trends of O. cleberi, given that it is apparently endemic to the Cerrado biodiversity hotspot.