A new echimyid genus (Rodentia, Caviomorpha) in Central Argentina: uncovered diversity of a Brazilian group of mammals in the Pleistocene

We describe a new extinct spiny rat, Proclinodontomys dondasi n. gen. n. sp. (Rodentia, Caviomorpha, Echimyidae), represented by a noteworthy-preserved skull and mandible from the early-middle Pleistocene outcrops at the coastal cliffs of southeastern Buenos Aires Province (Central Argentina). Phylogenetic analyses allow us to propose that the new species described here and the already known Eurzygomatomys mordax (Winge), represent a new genus closely related to the living Euryzygomatomys spinosus and Clyomys laticeps. The new genus differs from Euryzygomatomys and Clyomys by having much more procumbent upper incisors, a more developed fossa for the M. temporalis, more flared and laterally expanded zygomatic arches, frontal less markedly expanded posteriorly, jugals much deeper anteriorly than posteriorly, with the dorsal border descending more abruptly posteriorly, smaller orbital cavity, and external auditory meatus relatively smaller and slanted upward and backward. Several features ...