 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 <unk> , which included all " primitive " crocodilian relatives that lived in the Triassic . With the rise of phylogenetics , aetosaurs were later placed in a group called <unk> , which included many Triassic crurotarsans as well as later crurotarsans , including crocodilians . 
