Caviomorphs (Mammalia, Rodentia) from the Holocene of Rio Grande do Sul State, Brazil: Systematics and paleoenvironmental context

Abstract

The caviomorph rodents are scarcely known from the Quaternary record of Rio Grande do Sul State, Brazil. This work deals with caviomorphs from two sites, with datings including the Early to Late Holocene. The taxa recorded were: Cavia sp., C. aperea, C. magna, Ctenomys sp., Phyllomys sp., Myocastor coypus, Euryzygomatomys mordax, Dicolpomys fossor, the last two of which are extinct. A new fossil species, Clyomys riograndensis sp.nov. is also described. The stratigraphic distribution of these taxa allows us to suggest a slow and gradual climatic change during the Holocene and a mosaic environment with grasslands and gallery forests, which is indicated by the presence of fossorial animals that typify open areas, coexisting with taxa of forested areas.