New data on Abrawayaomys chebezi (Rodentia, Cricetidae), a poorly known South American sylvan rodent

Abstract

Abrawayaomys chebezi is a spiny sigmodontine believed endemic to the Atlantic Forest of Misiones Province, Argentina. The available knowledge is largely restricted to the holotype, the only fully vouchered specimen. Here, we detail a second specimen, a subadult male obtained in the Parque Provincial Urugua-í (Misiones). The morphology of this animal confirms several diagnostic traits of A. chebezi, such as its smaller size relative to Abrawayaomys ruschii, the type species of the genus, and the simplified occlusal structure of its molars. New data on soft anatomy indicate that chebezi has a unilocular-hemiglandular stomach, no gall bladder, and a complex tridigitate penis with an external surface covered by rounded spines. A rich parasite assemblage including fleas and mites was recorded from this animal. A preliminary review of the alpha taxonomy of Abrawayaomys suggests the possible existence of three different species in the genus, one still unnamed.