A new Brazilian Calomys Waterhouse, 1837 species is described based on morphologic and karyologic data. This species is endemic to the Cerrado of Central Brazil and allopatric with all other species of the genus Calomys. Its chromosome complement (2n = 46, AN = 66) is different from those described in other Calomys species. Morphometric analysis significantly distinguished this new species from other Calomys of the Brazilian fauna like C. callosus (Renger, 1830), C. expulsus (Lund, 1841) and C. tener (Winge, 1887) and placed it among the large-sized Calomys.
Brazilian Cerrado; Calomys; karyotype; morphology; new species
