Genus Necromys Ameghino, 1889

ULYSES F. J. PARDIÑAS; PABLO TETA; PABLO E. ORTIZ; J. PABLO JAYAT; JORGE SALAZAR-BRAVO

Mammals of South America, Volume 2

The University of Chicago Press

Año: 2015; p. 232 - 247

Necromys is one of the few highly polytypic sigmodontine genera that remains unrevised. With a mid-continental distribution, encompassing more than 5,400 km from Trinidad and Tobago to central Argentina and up to 30 included nominal forms, these mice have presented a continuous challenge for students of rodent systematics. Most contributions on Necromys taxonomy are biased to a single kind of evidence and focused on a limited geographic areas or species coverage. As exemplars, studies on metrics and morphology of Bolivian populations of N. amoenus, N. lactens, and N. lenguarum, the morphometric approaches to geographic variation in N. lasiurus and N. urichi, or the clarification of species boundaries between N. benefactus and N. obscurus from central Argentina and Uruguay deserve special mentioned. Two substantive studies established the baseline for our current understanding of the genus, and the present account of Necromys systematics. The first, which remains basically unpublished, was Reig?s (1972) morphological analyses, with a shortened version of his conclusions appearing in Reig (1987) and partial results presented posthumously in Reig (1994). The second is the molecular phylogenetic analyses of D?Elía, Pardiñas, Jayat, and Salazar-Bravo (2008), based on mtDNA cytochrome b sequences with a broad taxonomic and geographic coverage. The complex taxonomic and nomenclatorial history of Necromys is explained in part by the large geographic distribution of the genus but mostly by the gross morphological similarity of species in the genus to several species of Akodon (Akodontini) and Zygodontomys (Oryzomyini). Seven living and one fossil species are currently recognized in Necromys (Musser and Carleton 2005; D?Elía, Pardiñas, Jayat, and Salazar-Bravo 2008). Isolated in northern South America, Venezuela, Colombia, and Trinidad and Tobago, the N. urichi complex inhabits forests, grasslands, shrublands and montane habitats. Along the eastern Andean ranges and Puna habitats are three species that replace one another from north to south: N. punctulatus, N. amoenus, and N. lactens.