Upper Cretaceous vertebrates from El Anfiteatro area, Río Negro, Patagonia, Argentina

The first vertebrate remains from the Upper Cretaceous locality El Anfiteatro (northern Río Negro, Patagonia, Argentina) are described. Fossil remains were recovered in beds of Cerro Lisandro, Portezuelo, and Plottier formations. From the Cerro Lisandro Formation, remains of large fishes, dipnoans, titanosaur sauropod dinosaurs, and a variety of theropod dinosaurs (cf. Carcharodontosauridae, cf. Spinosauridae, cf. Abelisauria and Coelurosauria indet.) are reported. The Plottier Formation, in turn, has yielded remains of Chelidae turtles, crocodyliforms, titanosaur sauropods, theropods (cf. Carcharodontosauridae, Coelurosauria indet., cf. Unenlagiinae), and ornithopods. To date, the Portezuelo Formation has been the less prolific of all. Except for the record of a possible spinosaurid in the Cerro Lisandro Formation, the rest of the evidence obtained from El Anfiteatro is congruent with the record of other Patagonian sites where the Limayan and Neuquenian tetrapod associations were established.