The Ctenomys population from Anillaco, La Rioja Province, Argentina has been the subject of detailed studies of circadian rhythms, vocalization, ecology and spatial dynamics. However, the taxonomy and systematics of this population as well as populations of Ctenomys inhabiting Andean areas of this province is unknown. In this study, we present the phylogenetic relationship of the “Anillaco tuco-tuco” as well as of two other populations of Ctenomys, all distributed in the northern portion of La Rioja Province, Argentina. Based on molecular analyses and morphological comparisons, we reached to the conclusion that the “Anillaco tuco-tuco” population corresponds to the species Ctenomys famosus. In addition, an undescribed species, member of the “mendocinus” lineage of Ctenomys, is recognized in the Andean portions of the province.

The mammals of La Rioja, eight decades after Yepes. the mammals of the Province of La rioja are poorly known, due to the lack of systematic sampling and little interest in its survey. the single list of mammals was elaborated by José Yepes in 1936 mostly from materials collected by him in field trip conducted in several localities, including Sanagasta, Patquía, Famatina, Villa unión and La Sierra de Velasco. Here we present the first update to the list of Yepes, using the available literature, as well as the specimens collected by him and housed at the Museo Argentino de ciencias naturales "Bernardino rivadavia". the species listed account 70, showing an important increment from the 23 recorded by Yepes. However, since a large area of the province is still unexplored, we can expect future additions.