The type species, Arizonasaurus babbitti, was named by Samuel Paul Welles in 1947 on the basis of a few teeth and a maxilla, labelled as specimen UCMP 36232.

[3] The pelvic girdle in Arizonasaurus unites this taxon with Ctenosauriscus, Lotosaurus, Bromsgroveia, and Hypselorhachus.

[4] Together, newly identified pseudosuchian features act as evidence that poposaurids, such as Poposaurus, Sillosuchus, and Chatterjeea, and ctenosauriscids form a monophyletic group that is derived rauisuchians.

[3] Below is a phylogenetic cladogram simplified from Butler et al. in 2011 showing the cladistics of Archosauriformes, focusing mostly on Pseudosuchia:[5] Qianosuchus Arizonasaurus Xilousuchus Hypselorhachis Ctenosauriscus Bromsgroveia Waldhaus Taxon Poposaurus gracilis H Poposaurus gracilis Y Lotosaurus Sillosuchus Shuvosaurus Effigia Arizonasaurus is from the middle Triassic Moenkopi Formation of northern Arizona.

The presence of a poposauroid in the early Middle Triassic suggests that the divergence of birds and crocodiles occurred earlier than previously thought.