Pseudosuchia

Pseudosuchia (from Ancient Greek ψεύδος (pseúdos), meaning "false", and Σοῦχος (Soûkhos), meaning "Sobek") is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs", in contrast to the "bird-line archosaurs" or Avemetatarsalia. Despite Pseudosuchia meaning "false crocodiles", the name is a misnomer as true crocodilians are now defined as a subset of the group.

The clade Pseudosuchia is potentially equivalent to another term, Crurotarsi, even though the latter has a different, node-based definition: "all taxa the least inclusive clade containing Rutiodon carolinensis (Emmons, 1856), and Crocodylus niloticus (Laurenti, 1768)." Many paleontologists of the late 20th century took this proposal for granted, using Crurotarsi as the term for crocodilian ancestors. In 2011, a major revision of Triassic archosaur relations proposed that Rutiodons group, Phytosauria, was not as closely related to other traditional "crurotarsans", at least compared to avemetatarsalians such as pterosaurs and dinosaurs. Under that interpretation, Crurotarsi would be a much broader clade than Pseudosuchia. Other recent studies continue to support a more traditional phylogeny with phytosaurs as an early branch of Pseudosuchia. If the traditional interpretation is maintained, Pseudosuchia and Crurotarsi are roughly equivalent categories.