Revisiting the taxonomy of Ctenomys in northern Patagonia: new specimens and integrative new analyses

TAMMONE, MAURO N.; LACEY, EILEEN A.; CUÉLLAR SOTO, ERIKA; VOGLINO, DAMIÁN; PARDIÑAS, ULYSES F.J.

Congreso; 13th International Mammalogical Congress; 2023

Subterranean rodents in the genus Ctenomys are a significant component of mammalian assemblages in northern Patagonia, a mostly arid plateau encompassing about 700,000 km2. Collections in this region during the late 19th and early 20th centuries resulted in the description of several species (e.g., C. emilianus, C. haigi, C. maulinus, C. pontifex). Subsequently, little work has been conducted on the taxonomy of these rodents, particularly for populations inhabiting isolated interior lowlands. To begin addressing these gaps, recent field campaigns have focused on the southern Andes of Mendoza Province and the Atlantic coast of Río Negro Province. Comparisons of mitochondrial cyt-b sequences and cranial morphologies were then used to explore the phylogeographic diversity of ctenomyids in this region and to evaluate their taxonomic placement relative to recognized species of tuco-tucos. These analyses reveal that the mountainous region of northwestern Patagonia contains four distinct lineages of Ctenomys (i.e., maulinus, mendocinus, magellanicus, sociabilis). In contrast, the steppe plateau of northeastern Patagonia is occupied exclusively by members of the magellanicus lineage. This difference likely reflects Quaternary climate changes in Patagonia, where repeated glaciation events had profound impacts. Our findings highlight a potentially key role for montane versus steppe habitats in shaping diversification of tuco-tucos while revealing geographic gaps in sampling of Patagonian ctenomyids that will be the focus of future field campaigns.