Crurotarsi is a clade of archosauriform reptiles that includes crocodilians and stem-crocodilians and possibly bird-line archosaurs too if the extinct, crocodile-like phytosaurs are more distantly related to crocodiles than traditionally thought.

This traditional definition of Crurotarsi assumed that phytosaurs were crown-group archosaurs and more closely related to crocodilians than to birds.

[1] According to two studies published in 2011 by Nesbitt and coworkers, using either of these definitions leads to the inclusion of all other true archosaurs in Crurotarsi, due to the possibly basal phylogenetic position of the phytosaurs.

A more definitive group is Pseudosuchia, which is defined as all archosaurs closer to crocodiles than to birds (matching the traditional content of Crurotarsi).

Arcucci named Crurotarsi in 1990, defining it as "Parasuchia [phytosaurs], Ornithosuchidae, Prestosuchus, Suchia, and all descendants of their common ancestor".

[7] Below is a cladogram after Nesbitt & Norell (2006) and Nesbitt (2007) with Crurotarsi in its traditional sense encompassing just crocodile-line archosaurs:[8][9] †Euparkeria †Proterochampsidae to Avemetatarsalia †Phytosauria †Aetosauria Crocodylomorpha †Ornithosuchidae †Rauisuchidae †Prestosuchidae †Arizonasaurus †Lotosaurus †Sillosuchus †Shuvosaurus †Effigia Cladogram after Brusatte, Benton, Desojo and Langer (2010):[10] †Erythrosuchus †Euparkeria †Proterochampsidae to Avemetatarsalia †Phytosauria †Aetosauria †Gracilisuchus †Erpetosuchus Crocodylomorpha †Revueltosaurus †Ornithosuchidae Arganasuchus Fasolasuchus Stagonosuchus Ticinosuchus Saurosuchus Batrachotomus Prestosuchus Tikisuchus Rauisuchus Postosuchus Teratosaurus Yarasuchus Qianosuchus Arizonasaurus Bromsgroveia Lotosaurus Poposaurus Sillosuchus Shuvosaurus Effigia In 2011, Sterling J. Nesbitt found phytosaurs to be the sister taxon of Archosauria, and therefore not crocodile-line archosaurs.