Pseudochampsa

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Pseudochampsa is an extinct genus of crocodile‑like archosauriform from the Late Triassic of Argentina. It contains a single species, Pseudochampsa ischigualastensis, which lived in the Carnian to earliest Norian stages and was found in the Ischigualasto Formation of northwestern Argentina.

Discovery and naming
The holotype skull and skeleton of Pseudochampsa ischigualastensis is known from specimen PVSJ 567, discovered at Valle Pintado in the Ischigualasto Basin. It comes from the Cancha de Bochas Member of the Ischigualasto Formation. The species was first described in 2012 as Chanaresuchus ischigualastensis, but in 2014 it was moved to its own genus, Pseudochampsa, giving the new combination Pseudochampsa ischigualastensis. The name Pseudochampsa means “false crocodile,” referring to its crocodile‑like body shape, and ischigualastensis refers to the Ischigualasto Formation where it was found.

What it was like
Pseudochampsa is known from a nearly complete and articulated skeleton that includes a skull, jaws, most of the backbone, ribs, gastralia, the shoulder girdle, both arms, a partial pelvis, and the hind limbs. It shows a crocodile‑like body typical of proterochampsids, a group of Triassic archosauriforms. The skull and skeleton reveal features that set it apart from closely related animals and helped scientists understand its place in the family tree.

Etymology and type species
The type species is Pseudochampsa ischigualastensis. The genus name combines Greek roots meaning “false” and “crocodile,” highlighting its crocodile‑like appearance, while the species name points to the Ischigualasto Formation.

Description and distinguishing traits
When first described, some features were used to group the animal with Chanaresuchus. Later work showed that those traits were not exclusive to that genus, and that Pseudochampsa has its own distinctive combination of characteristics. Among these are skull and jaw features and particular details of the vertebrae and osteoderms that differentiate it from other proterochampsids. In short, Pseudochampsa has a unique set of traits that justified placing it in its own genus rather than with Chanaresuchus.

Phylogeny
Phylogenetic analyses place Pseudochampsa within Proterochampsia and Proterochampsidae, a group of Triassic archosauriforms. In the 2014 study that reassessed its status, Pseudochampsa and the related species were placed in a polytomy with Gualosuchus, meaning their exact relationships are not fully resolved. This work also supported moving Pseudochampsa away from Chanaresuchus, reinforcing its status as a separate genus within Proterochampsidae.

Significance
Pseudochampsa adds to our understanding of Triassic reptiles in South America and helps clarify the diversity of proterochampsids in the Ischigualasto ecosystem. Its discovery and reclassification highlight how new analyses can change how we group ancient reptiles and how they are related to each other.