Description of a new species of arboreal rat of the Rhiphidomys fulviventer group, from Venezuela (Rodentia: Cricetidae)

Arboreal rats of the genus Rhipidomys, belong to a taxonomic group of Neotropical distribution, included in the tribe
Thomasomyini. In Venezuela, the Rhipidomys fulviventer group contains four taxa (R. fulviventer, R. tenuicauda, R. venustus,
and R. wetzeli), only found in high elevation cloud forests and lowland rainforests. Because collections to date do not
represent a thorough sampling of their geographic range, taxonomic arrangement of some taxa (e. g., Rhipidomys venustus),
has been controversial. However, new specimens collected in recent years provide novel insights into the biogeographic
variation of the genus Rhipidomys. In this article, we evaluate the taxonomy and geographic distribution of R. venustus
based on a morphometric and morphological review that included integument, skull, teeth and post-cranial skeleton.
Specimens examined cover the entire geographic range of this species. The results showed significant differences between
populations, and supports the recognition of a new species inhabiting cloud forests in the Cordillera de la Costa Central
and the Sistemas de colinas Lara-Falcón, Venezuela. The new species is larger than any of its congeners in the R. fulviventer
group in this country. It shows dorsal and ventral coloration differences and unique qualitative characters associated with
integument, skull and post-cranial skeleton. The geographic distribution of R. venustus is updated, and restricted to the
Cordillera de Mérida. Remarks on the ecology and conservation status of the new taxon are also presented.