Crurotarsi

The Crurotarsi are one of the two main groups of archosaurs. It includes the archosaurs (living today are crocodiles and birds). It also includes all their ancestors and relatives right back to the early Triassic period, including the Pseudosuchia.Sereno, Paul 1991. Basal archosaurs: phylogenetic relationships and functional implications. Journal of Vertebrate Paleontology 11 (Suppl. 4): 1–51.

Crurotarsi:
 Avemetatarsalia
 †Pterosauria
 †Dinosauria
 Aves (birds)
  The crocodile line Pseudosuchia
 †Phytosauria: semi-aquatic long-snouted types
 †Aetosauria: quadrupedal armoured herbivores
 †Ornithosuchidae: look rather like dinosaurs
 Crocodylomorpha (Crocodilia and their ancestors)
 †Rauisuchia ? uncertain group, includes some large-bodied quadrupedal predators

Both main groups of Archosaurs are defined by features of their ankle joints.Sereno P.C. & Arcucci A.B. 1990. The monophyly of crurotarsal archosaurs and the origin of bird and crocodile ankle joints. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen 180: 21–52. Nesbitt S.J. 2011. The early evolution of archosaurs: relationships and the origin of major clades. Bulletin of the American Museum of Natural History 352: 1–292. 

 References 

Category:Archosaurs