Molecular systematics of the South American marsh rats of the genus Holochilus (Muroidea, Cricetidae, Sigmodontinae)

GUILLERMO D?ELÍA, J. DELTON HANSON, MATTHEW R. MAULDIN, PABLO TETA AND ULYSES F. J. PARDIÑAS

JOURNAL OF MAMMALOGY

ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS

Lugar: Lawrence; Año: 2015

0022-2372

We present a comprehensive systematic study of Holochilus, a sigmodontine genus of large herbivorous and semi-aquatic rodents widely distributed in South America. Remarkably, given its complex taxonomic history and large economic and epidemiological importance, the alpha taxonomy of Holochilus has not benefited from a molecular based approach. The study is based on sequences of 1 mitochondrial and 3 nuclear genes that were analyzed by maximum likelihood and Bayesian inference. Analyses include sequences of specimens from localities from Argentina, Bolivia, Brazil, Colombia, Paraguay, Peru, Suriname, and Uruguay, representing all but 2 of the species currently recognized in the genus. The mitochondrial genealogy, which is the one with the large geographic coverage of Holochilus, recovered 6 species level lineages that form 2 well supported species group: the brasiliensis species group formed by H. brasiliensis, and H. vulpinus and the sciureus species group composed by H. chacarius, H. sciureus, and 2 apparently unnamed forms. Remarkably, in the cytochrome b gene analyses the 2 species groups are not sister to each other; i.e., Holochilus is not monophyletic, although these topologies lack significant support. However, the monophyly of Holochilus was supported by the 3 nuclear genes as well as by the combined analysis of all 4 genes. These genealogical results are the basis of taxonomic and biogeographic considerations.