Capybaras (Rodentia: Hystricognathi: Hydrochoeridae) from the late Pleistocene of southern Brazil

The Hydrochoeridae are caviomorph rodents of medium to large size. They are euhypso- dont and elasmodont, with a peramorphic trend to increase the number of M3 prisms from basal to advanced taxa. The diversity of this family was higher during the Miocene/Pliocene, but today they are represented by a single genus, with two species, Hydrochoerus hydrochaeris (Linnaeus, 1766) and H. isthmius GoLdman, 1912. In this paper we described fossil remains assigned to H. hydro- chaeris from Touro Passo Creek (Touro Passo Formation, upper Pleistocene, Lujanian Age) in west- ern Rio Grande do Sul State, southern Brazil. The main charac ters used to assign these specimens to H. hydrochaeris are: M3 with 13 free prisms, upper diastema shorter than the maxillary cheek teeth, rostral area relatively wide, smaller proportion s than Neochoerus Hay, 1926 and larger than H. isthmius. The presence of H. hydrochaeris suggests that in late Pleistocene of western Rio Grande do Sul State, probably existed environments with permanent water bo dies.

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