 Aetosaurs belong to Pseudosuchia, a clade of archosaurs that includes living crocodilians and is characterized by the distinctive structure of the ankle bones. Aetosaurs were traditionally referred to a (now obsolete) group called the thecodonts, which included all "primitive" crocodilian relatives that lived in the Triassic. With the rise of phylogenetics, aetosaurs were later placed in a group called Suchia, which included many Triassic crurotarsans as well as later crurotarsans, including crocodilians.
