Ctenomys famosus is one of the less known species of the genus, both in systematic and in phylogenetic aspects, as well as in its distribution and natural history. So far the only known specimens of this species are those from the type series, collected at the two localities mentioned in the original description, in La Rioja province, Argentina. We here provide new information about the species as well as some comments about the type locality, and add a new point to its known geographical distribution. In addition, the capture of topotypes allowed us to add unpublished information on molecular, morphological and cranial variables of the species. The phylogenetic analysis of mitochondrial gene cytochrome b sequences positions C. famosus in the context of the existing phylogenetic hypotheses and proposals for the genus as belonging to the "mendocinus group". This information can serve as a basis for future research that favors clarifying the evolutionary panorama of the group at the regional level, as well as for completing the existing relationships within the complex of the Argentine species of the genus.