First hadrosaurid dinosaur remains from Neuquén province

CRUZADO-CABALLERO, PENÉLOPE; FILIPPI, LEONARDO S.; BARRIOS, FRANCISCO; MÉNDEZ, ARIEL H.; PAULINA-CARABAJAL, ARIANA; PREVITERA, MARÍA ELENA; GARRIDO, ALBERTO C.

Villa El Chocón

Jornada; III Jornadas de Paleontología de la Cuenca Neuquina; 2021

Museo Municipal "Ernesto Bachmann"

In the hadrosaur clade, paleobiodiversity continually fluctuates with the emergence of new taxa. But these occur mainly in the continents of the Northern Hemisphere. With respect to the southern record, it is poorer both in paleobiodiversity and in new finds, which have been produced exclusively in Argentina, Chile, and Antarctica. Of these, the Argentine record is the most abundant of all, which is distributed among the provinces of La Pampa, Río Negro, Chubut, and Santa Cruz. Here we present the first remains found in the vicinity ?Cerro Overo-La Invernanda? area near the city of Rincón de los Sauces, where continental sediments of the Allen Formation (Maastrichtian, latest Cretaceous) crop out. The Upper Cretaceous formations in this area have long been shown to be very fossil-rich, but to date no ornithopod remains with a Maastrichtian age have been found. The new rest found (MAU-Pv-CO-667) is a vertebral centrum corresponding to a middle cervical vertebra. Despite the poor state of preservation, it allows us to recognize the characteristics of the Hadrosauridae clade: heart-shaped articular surfaces with the anterior one strongly opisthocoelic, and a centrum wider than height with a length similar to the height. Because the cervical vertebrae are indistinct from those of all other hadrosaurids, MAU-Pv-CO-667 cannot be assigned beyond indeterminate hadrosaurid. These new fossils represent the first record of this dinosaur group for the province of Neuquén and fill a gap in their paleobiogeographic distribution, as Neuquén is the only Patagonian province that remained without hadrosaurid record.