A new proterochampsid archosauriform from the Middle-Upper Triassic of Southern Brazil

The holotype was excavated at the Linha Várzea 2 (Becker) Site, located in the municipality of Paraíso do Sul, Rio Grande do Sul, Brazil. The fossils from this locality places it within the Dinodontosaurus Assemblage Zone, which is Ladinian to early Carnian in age according to biostratigraphic investigations. The new taxon is the second proterochampsid described from the Pinheiros-Chiniquá Sequence and represents one of the oldest known members of the clade worldwide.

An interesting aspect of R. beckerorum gen. et sp. nov. is its phylogenetic position because it is more closely related to Proterochampsa than to rhadinosuchine proterochampsids. Therefore, the discovery of the new proterochampsid partially fills a long ghost lineage extending from the Middle Triassic to the early Late Triassic. Furthermore, the presence of two proterochampsid species within the Pinheiros-Chiniquá Sequence deposits supports the hypothesis of significant ecomorphological diversity among proterochampsians in Triassic environments.