Morphological diagnosis and geographic distribution of Atlantic forest red-rumped mice of the genus Juliomys (Rodentia: Sigmodontinae)

Abstract

Recognition and identification of red-rumped mice of the genus Juliomys González, 2000 has been a problem among many mammalogists, and specimens of this genus are commonly confused with other Atlantic Forest sigmodontine rodents. Herein we provide an expanded diagnosis for the genus based on the analyses of the three living species of Juliomys, and provide morphological comparisons to the small bodied and bright colored rodents Rhagomys rufescens (Thomas, 1886) and Oligoryzomys flavescens (Waterhouse, 1837), which occur in sympatry with Juliomys spp. in forested areas of southeastern Brazil. These taxa are superficially similar, and are therefore commonly misidentified in the field and museum collections. We also provide morphometric data and a key to the living species of Juliomys, and an updated distribution map of the genus and its species. © 2011 Sociedade Brasileira de Zoologia.