Proterochampsa barrionuevoi (Archosauriformes: Proterochampsia) from the Late Triassic (Carnian) of Argentina and a phylogenetic analysis of Proterochampsia

A restudy of Proterochampsa barrionuevoi, a proterochampsian archosauriform from the Late Triassic Ischigualasto Formation in Argentina, reveals distinct autapomorphies that diagnose the genus. These include unique cranial features such as prominent dermal sculpturing with ridges and nodular protuberances, a hook-like quadratojugal projection, and specific morphological traits of the premaxilla, maxilla, and angular. The study also identifies Proterochampsa nodosa as a valid species, distinguished by fewer cranial ridges with larger protuberances and other cranial characteristics. Phylogenetic analysis supports the monophyly of Proterochampsia, a group that includes Proterochampsa, Chanaresuchus bonapartei, Gualosuchus reigi, Tropidosuchus romeri, and Cerritosaurus binsfeldi. The temporal separation between basal proterochampsians (Proterochampsa and Cerritosaurus) with earliest records in the Late Triassic and other members (Chanaresuchus, Gualosuchus, Tropidosuchus) from the Middle Triassic suggests a hidden diversity of Proterochampsia in the Middle Triassic.

DILKES, D., & ARCUCCI, A. (2012). Proterochampsa barrionuevoi (Archosauriformes: Proterochampsia) from the Late Triassic (Carnian) of Argentina and a phylogenetic analysis of Proterochampsia. Palaeontology, 55(4), 853–885. Portico. https://doi.org/10.1111/j.1475-4983.2012.01170.x