Systematics, phylogeny and evolutionary pattern of the hystricognath rodent Eumysops (Echimyidae) from the Plio–Pleistocene of southern South America

The results of a systematic and stratigraphic review of the genus, and of phylogenetic analyses based on both morphology and a combined morphological–molecular dataset in the context of extant representatives, are presented here. Recognised diversity includes four previously described species plus a new one from the late Pliocene.

These species form a well-supported monophyletic clade, sister to the late Miocene † Pampamys and the extant Thrichomys . The position of † Eumysops –† Pampamys – Thrichomys in a major clade including non-‘eumysopine’ echimyids constrains the traditional taxon Eumysopinae only to these three genera. Phylogeny and stratigraphic distribution of † Eumysops species suggest an essentially cladogenetic evolutionary pattern.