Northern Patagonia: exploring a contact zone between two widely distributed lineages of Ctenomys (Rodentia: Ctenomyidae)

TAMMONE, MAURO N; PARDIÑAS, ULYSES FJ; LACEY, EILEEN A

Congreso; 100th Annual Meeting of the American Society of Mammalogists; 2021

The South American genus Ctenomys is well represented throughout much of southern Patagonia by the polytypic ?magellanicus? lineage. Two additional lineages, both restricted to the Patagonian Andes, are the monotypic ?sociabilis? and ?maulinus? clades. In comparison, the taxonomy of Ctenomys in northern Patagonia (southern Mendoza, Neuquén and Río Negro Provinces) remains poorly resolved. This region consists of ca. 160,000 km2 of mostly homogenous habitat ranging from the Andes to the Atlantic coast. Descriptions of Ctenomys from this area are restricted to a few specimens studied by Thomas in the early 20th century. Here, we report on phylogenetic relationships among recently sampled populations of Ctenomys from northern Patagonia. Based on mitochondrial sequences and morphological comparisons, our preliminary results indicate that the southern ?magellanicus? lineage extends north along the Andes in steppe habitat to at least Mendoza Province (35°S). To the east is an extensive contact zone between the ?magellanicus? lineage and the widely distributed ?mendocinus? lineage from Central Argentina. In this area, the ?mendocinus? lineage appear not to penetrates far beyond the Colorado and Negro rivers, however this hypothesis require to be confirmed. We propose that these water courses may represent distributional break for lineages of Ctenomys in northern Patagonia. Future phylogeographic analyses should yield additional insights into patterns and processes of diversification among Ctenomys from this still poorly sampled portion of South America.