 Aetosaurs ( aetosaur / <unk> / ; order name Aetosauria / <unk> / ; from Greek , <unk> ( aetos , " eagle " ) and σαυρος ( 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 <unk> 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 . 
