Species limits and phylogenetic relationships within Necromys (Cricetidae, Sigmodontinae): molecular evidence

D'ELÍA, G.; PARDIÑAS, U.F.J.; SALAZAR-BRAVO, J.; JAYAT, P.

University of Massachusetts at Amherst, Massachusetts, USA

Otro; 86th Annual Meeting of the American Society of Mammalogists; 2006

ASM

In this talk we present the most complete systematic study of sigmodontine mice of the genus <i>Necromys</i>; it is based on sequences of the cytochrome b gene. The analyses include sequences of 58 specimens from 47 localities from Argentina, Bolivia, Brazil, Colombia, Paraguay, Peru, Uruguay and Venezuela representing the following nominal forms: <i>amoenus</i>, <i>benefactus</i>, <i>fuscinus</i>, <i>lactens</i>, <i>lasiurus</i>, <i>lenguarum</i>, <i>obscurus obscurus</i>, <i>obscurus scaglarium</i>, <i>punctulatus</i>, <i>temchuki liciae</i>, and <i>temchuki temchuki</i>.  Our results show a well resolved topology with a broad range of nodal support. Among the results obtained we stress the following. 1) The monophyly of the genus is poorly supported; There is a large polytomy at the base of <i>Necromys</i>; 2) Lowland species form a monophyletic group; 3) Within this clade <i>N. obscurus</i> is sister to the remaining species; 4) Haplotypes recovered from specimens assigned to <i>N. benefactus</i>, <i>N. temchuki</i>, and <i>N. lasiurus</i> form a clade, but these taxa do not form reciprocally monophyletic groups; in addition haplotypes show only reduced geographic structure. These results, discussed together with degrees of genetic variation and patterns of morphologic variation, are the base of taxonomic, nomenclatorial and biogeographic considerations.