Paleoclimatic implications of the presence of Clyomys (Rodentia, Echimyidae) in the Pleistocene of central Argentina

The presence of the Echimyidae Eumysopinae Clyomys in Ensenadan (Early-Middle Pleistocene) sediments cropping out northeast of Mar del Plata and south of Necochea (costal region of Buenos Aires province, Argentina) is reported. This is the first citation of Clyomys in Argentina and the first post-Pliocene record of echymids at this latitude. These remains represent a species closely related to the extant representatives of the genus, which live at least 1600 km north of the new localities. These fossils suggest that a southward expansion of the Brazilian fauna occurred during a warm and humid pulse in the Pleistocene.