Early archosauromorph remains from the Permo-Triassic Buena Vista Formation of north-eastern Uruguay

EZCURRA, M. D.; VELOZO, P.; MENEGHEL, M.; PIÑEIRO, G.

PeerJ

PeerJ, Inc.

Lugar: San Francisco; Año: 2015 vol. 3 p. 1 - 26

2167-8359

The Permo-Triassic archosauromorph record is crucial to understand the impactof the Permo-Triassic mass extinction on the early evolution of the group and itssubsequent dominance in Mesozoic terrestrial ecosystems. However, the Permo-Triassic archosauromorph record is still very poor in most continents and hampersthe identification of global macroevolutionary patterns. Here we describe cranialand postcranial bones fromthe Permo-Triassic Buena Vista Formation of northeasternUruguay that contribute to increase the meagre early archosauromorph recordfrom South America. A basioccipital fused to both partial exoccipitals and threecervical vertebrae are assigned to Archosauromorpha based on apomorphies or aunique combination of characters. The archosauromorph remains of the BuenaVista Formation probably represent a multi-taxonomic assemblage composed ofnon-archosauriform archosauromorphs and a ?proterosuchid-grade? animal. Thisassemblage does not contribute in the discussion of a Late Permian or Early Triassicage for the Buena Vista Formation, but reinforces the broad palaeobiogeographicdistribution of ?proterosuchid grade? diapsids in Permo-Triassic beds worldwide.