A new abelisauroid theropod from northwestern Patagonia

摘要

The Argentinean record of abelisauroid theropods begins in the Early Cretaceous (Ligabueino) and spans most of the Late Cretaceous, from Cenomanian (Ilokelesia, Xenotarsosaurus, and Ekrixinatosaurus) to Campanian-Maastrichtian (Abelisaurus, Carnotaurus, Aucasaurus, and Noasaurus). A fragmentary specimen of a theropod dinosaur was collected in 2000 from the middle section of the Lisandro Formation (Turanian?) at Cerro Bayo Mesa, Neuquen Province, Argentina. The fossil-bearing level, which is part of the Lisandro Formation that also yielded the remains of the basal ornithopod Anabisetia saldiviai, corresponds to a reddish, massive mudstone linked with fluvial channel deposits. The theropod identified as MCF-PVPH-237 is an abelisauroid theropod that increases our knowledge about the evolution of South American Abelisauroidea and is the first record of this clade from the Lisandro Formation.