The skull with mandible of a fossil tremarctine bear from Ubajara county, northeastern Brazil, is described and compared to other specimens belonging to the nominal species, Arctodus (Pararctotherium) brasiliensis. It differs from the other almost complete skull, from Minas Gerais State, in having a shorter, more slender rostrum, larger braincase, and smaller teeth. We also propose a phylogenetic hypothesis and correspondent classification for the genera of Tremarctinae, using cladistic methodology. Arctodus and Arctotherium are recognized as separate genera, with the latter including two subgenera, Arctotherium and Pararctotherium. The Ubajara bear is tentatively identified as Arctotherium (P.) brasiliense (comb, nov.).