The fossil record of Abelisauridae (Dinosauria, Theropoda) from the Upper Cretaceous of Patagonia

MÉNDEZ, ARIEL H.; GIANECHINI, FEDERICO A.; FILIPPI, LEONARDO S.; JUÁREZ VALIERI, RUBÉN D.

San Luis

Otro; Reunión de Comunicaciones de la Asociación Paleontológica Argentina; 2017

The record of Abelisauridae from Patagonia (formed by successive less inclusive clades such as Brachyrostra, Furileusauria and Abelisaurinae) is the most abundant and diverse among the different groups of theropods that inhabited that region during the Upper Cretaceous, with more than two dozen of specimens. This record clearly shows a sequence from more basal to more derived forms of this theropod lineage. In the lower formations of the Upper Cretaceous (Candeleros, Huincul and Cerro Lisandro of the Neuquina Basin and Bajo Barreal of the Golfo de San Jorge Basin, Cenomanian-Turonian) the record includes basal abelisaurids and basal brachyrostrans. In the ?intermediate? formations (Portezuelo, Plottier, Bajo de la Carpa of the Neuquina Basin, Turonian-Santonian) are recorded brachyrostrans and furileusaurians, while in the higher Cretaceous (Anacleto and Allen formations of the Neuquina Basin, and La Colonia Formation of the Somuncurá Massif, Campanian-Maastrichtian) are documented brachyrostrans, furileusaurians and abelisaurines. This study enables the identification of evolutionary patterns in the Patagonian basins (although there is no accurate data on the presence of abelisaurids in the Austral Basin). In turn, the study will allow comparisons with other South American basins (e.g., Bauru Basin) in order to obtain information on vicariance and diversification processes occurring during the Upper Cretaceous in South America. This evolutionary pattern should be placed in the context of current phylogenetic models to identify possible replacements between coexisting morphs.