A Multigene Phylogeny for Oecomys (Rodentia: Cricetidae: Sigmodontinae) with Descriptions of New and Revalidated Taxa and a Partial Species-Group Classification

We report phylogenetic analyses of a multigene dataset for 24 species of the Neotropical cricetid genus Oecomys, including one new species from western Amazonia (O. hiceae) and a revalidated trans-Andean species (O. trabeatus). In addition, we analyze sequence data from four species that have not previously been included in any molecular analysis (O. flavicans, O. phaeotis, O. speciosus, and O. trinitatis sensu stricto) and from historical specimens of O. concolor (a species represented in previous analyses by sequences of problematic homology). Our results provide strong support for a monophyletic Rutilus Group (including O. hiceae, O. rutilus, O. trabeatus), a Bicolor Group (O. bicolor, O. cleberi, O. nanus, O. jamari, O. phaeotis), and a Mamorae Group (O. franciscorum, O. mamorae). We tentatively recognize two other clades that are less strongly supported by our analytic results but that seem to merit heuristic recognition: a Concolor Group (O. concolor, O. speciosus) and a Trinitatis Group (O. catherinae, O. flavicans, O. matogrossensis, O. rex, O. trinitatis). Future taxonomic progress will require sequence data from additional genes, revisionary studies of still problematic species (e.g., O. bicolor, O. trinitatis), and fresh collections from hitherto poorly surveyed regions.