Proterochampsa barrionuevoi (Reig 1959, PVSJ 77) Late Triassic, ~210 mya,~40 cm skull length, was considered a sister to Proterosuchus and archosaurs. Here, Proterochampsa was derived from a sister to Chanaresuchus and is a sister to Pseudochampsa.

Distinct from Chanaresuchus, the skull of Proterochampsa was further flattened and the postorbital portion of the skull was shortened and compressed. An antorbital fenestra without a fossa was present. The upper temporal fenestrae were reduced. Lateral temporal fenestrae were present. The teeth were elongated and curved.

A recent report on archosaur relations (Brusatte et al. 2010) placed Proterochampsa at the base of the clade that produced dinosaurs and pterosaurs. Ridiculous for dozens of reasons, yet this was one of many such studies with similar results. Unsupportable and illogical results such as these are a direct result of inappropriate exclusions and inclusions in the taxon list resulting in "by default" nestings.

A new report by Trotteyn (2011) reveals much of the missing post-crania. PVSJ 606 was at least twice as large as the holotype. It was found in the Ischigualisto Formation of the Late Triassic.

The skull of the PVSJ 606 was relatively enormous! It was as long as the presacral vertebral column. The various fenestrae were relatively smaller. The premaxilla was shorter and the post-orbital area was more robust. The premaxilla was not squared off. Do these differences, plus the major size difference mean the new specimen is a new species? Probably.

Brusatte SL , Benton MJ , Desojo JB and Langer MC 2010. The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida), Journal of Systematic Palaeontology, 8:1, 3-47.

Reig OA 1959 Primeros datos descriptivos sobre nuevos Reptiles Arcosaurios del Triasico de Ischigualsto (San Juan, Argentina): Revista de la Asociacion Geologica Argentina, tomo 13, n. 4, p. 257-270.

Trotteyn MJ and Haro JA. In Press. The braincase of a specimen of Proterochampsa Reig (Archosauriformes: Proterochampsidae) from the Late Triassic of Argentina. Paläontologische Zeitschrift. Published on-line May 11 2010. DOI 10.1007/s12542-010-0068-7

Trotteyn MJ 2011. Material postcraneano de Proterochampsa barrionuevoi Reig, 1959 (Diapsida: Archosauriformes) del Triásico Superior del centro-oeste de Argentina. Ameghiniana 48:424-446.

Trotteyn MJ 2011. Revisión osteologica, análisis filogenético y paleoecología de proterochampsidae (Reptilia - Archosauriformes). Tesis Doctoral. Instituto y Museo de Cienciea Naturales Universidad Nacional de San Juan. CONICET.

wiki/Proterochampsa