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

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

San Luis

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

Asociación Paleontológica Argentina y Universidad Nacional de San Luis

The record of Abelisauridae from Patagonia (formed by successive less inclusive clades such as Brachyrostra, Furileusauriaand Abelisaurinae) is the most abundant and diverse among the different groups of theropods that inhabited that regionduring the Upper Cretaceous, with more than two dozen of specimens. This record clearly shows a sequence from morebasal to more derived forms of this theropod lineage. In the lower formations of the Upper Cretaceous (Candeleros, Huinculand Cerro Lisandro of the Neuquina basin and Bajo Barreal of the Golfo de San Jorge basin, Cenomanian?Turonian) the recordincludes basal abelisaurids and basal brachyrostrans. In the ?intermediate? formations (Portezuelo, Plottier, Bajo de la Carpaof 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 ofevolutionary patterns in the Patagonian basins (although there is no accurate data on the presence of abelisaurids in theAustral basin). In turn, the study will allow comparisons with other South American basins (e.g., Bauru basin) in order to obtaininformation on vicariance and diversification processes occurring during the Upper Cretaceous in South America. Thisevolutionary pattern should be placed in the context of current phylogenetic models to identify possible replacementsbetween coexisting morphs.