Stagonolepidid

Aetosaurs Temporal range: Late Triassic, 231.4–203 Ma PreЄ Є O S D C P T J K Pg N
Two Typothorax in their environment
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Suchia
Order:	†Aetosauria Lydekker, 1887
Subgroups
† Aetosauroides † Stagonolepididae † Aetosaurus † Coahomasuchus † Neoaetosauroides † Calyptosuchus † Stagonolepis † Aetobarbakinoides † Typothoracisinae † Desmatosuchinae

Aetosaurs (aetosaur /eɪˌɛtoʊˈsɔːr/; order name Aetosauria /eɪˌɛtoʊˈsɔːriə/; from Greek, (aetos, "eagle") and (sauros, "lizard")) are an extinct order of heavily armoured, medium- to large-sized Late Triassic herbivorous archosaurs. They have small heads, upturned snouts, erect limbs, and a body covered by plate-like scutes. All aetosaurs belong to the family Stagonolepididae. Two distinct subdivisions of aetosaurs are currently recognized, Desmatosuchinae and Aetosaurinae, based primarily on differences in the morphology of the bony scutes of the two groups. Over 20 genera of aetosaurs have been described, and recently there has been controversy regarding the description of some of these genera.

Aetosaur fossil remains are known from Europe, North and South America, parts of Africa and India. Since their armoured plates are often preserved and are abundant in certain localities, aetosaurs serve as important Late Triassic tetrapod index fossils. Many aetosaurs had wide geographic ranges, but their stratigraphic ranges were relatively short. Therefore, the presence of particular aetosaurs can accurately date a site that they are found in.