Aetobarbakinoides

Aetobarbakinoides is an extinct genus of stagonolepidid aetosaur known from the Late Triassic of Rio Grande do Sul state, southern Brazil. Fossils have been found from the Santa Maria Supersequence of the late Carnian and early Norian stages, making Aetobarbakinoides one of the oldest aetosaurs. The type species, A. brasiliensis, was named in 2012, and is notable for being described primarily by features of the vertebrae; most other aetosaurs are diagnosed by features in bony plates called osteoderms, which are by far the most common material. Although placed in a basal phylogenetic position among aetosaurs, Aetobarbakinoides is closely related to both desmatosuchines and typothoracisines, two derived clades of aetosaurs.

Aetobarbakinoides is known only from the holotype specimen CPE2 168, a partially articulated partial postcranial skeleton which housed at the Coleção Municipal in São Pedro do Sul. It was found near the city of São Pedro do Sul, in the center of Rio Grande do Sul, Brazil. It was collected in the Inhamandá locality, from the Hyperodapedon Assemblage Zone, Sequence 2 of the Santa Maria Supersequence (formerly known as Santa Maria Formation) which dates back to the late Carnian and earliest Norian stages of the Late Triassic. CPE2 168 was assigned by Lucas & Heckert (2001) to Stagonolepis robertsoni. It is the first aetosaur to be diagnosed in its original description without osteoderms, the most common material associated with these reptiles. Along with the genus Aetosauroides from Argentina and Brazil and Stagonolepis robertsoni from Scotland, Aetobarbakinoides is among the oldest aetosaurs. Its presence in South America indicates that aetosaurs had a wide geographic distribution early in their history. Aetobarbakinoides is most closely related to Aetosauroides and Neoaetosauroides. Features of its osteoderms suggest a close relationship with aetosaurines, but its vertebrae are more similar to desmatosuchines.