Proterotheriidae and Macraucheniidae (Litopterna, Mammalia) from the Pleistocene of Rio Grande do Sul State, Brazil

New materials of the order Litopterna from the late Pleistocene (Lujanian) of Rio Grande do Sul State are presented here. The specimens are an astragalus and calcaneum, assigned to cf. Neolicaphrium recens, and fragments of mandible, humeri, tibia and fibula, astragali, besides vertebrae and metatarsal, all of them attributed to Macrauchenia patachonica. The material described here comes from the municipalities of Santa Vitria do Palmar (Hermenegildo Beach, Chu Creek), Uruguaiana (Touro Passo Creek), Alegrete (Sanga da Cruz Creek) and Pantano Grande (Sanga Borba Creek). The record of these taxa in the Lujanian of Rio Grande do Sul State shows a greater similarity with the fauna in the same latitudinal belt of Argentina and Uruguay than that of the intertropical region.