NEW SAURIAN EVIDENCE FROM CANDELEROS FORMATION (CENOMANIAN; UPPER CRETACEOUS) OF SOUTHERN NEUQUÉN BASIN (EL SAUCE, PATAGONIA, ARGENTINA)

BELLARDINI, F.; BAIANO, M.A.; MANIEL, I.J.; GARRIDO, A.C.; WINDHOLZ G.J.; PINO, D.; MESO, J.G.; CIAFFI, A.; CORI, R.

Congreso; RCAPA 2022; 2022

The fluvial deposits of the Candeleros Formation widely outcrop in the Neuquén Basin, preserving an abundant and diversified saurian fauna of the “Middle” Cretaceous of northern Patagonia. The fossil record of the Candeleros Formation counts with many fossiliferous sites in Rio Negro and Neuquén Provinces; however, most of them come from the upper section of the unit. In this contribution, we report several saurian evidence from a new fossiliferous locality of El Sauce (Picún Leufú, Neuquén Province), where the lower section of the Candeleros Formation outcrops. Recent fieldworks allowed the finding of: several axial and appendicular sauropod remains, an almost complete femur that tentatively refers to an indeterminate, large-sized theropod dinosaur, some isolated plastron elements of indeterminate turtles, and isolated sauropod, pterosaur, and tridactyl dinosaur footprints. The sauropod specimens come from different sites on one laterally extended, fossiliferous level composed by grey, fine sandstones and green to purple mudstones, whereas the theropod femur and the footprints were found on brown coarse sandstones, all of which outcrop at the base of the Candeleros Formations. The diversified faunal composition recorded in the new locality of El Sauce is concordant with the slightly older Lohan Cura Formation, suggesting the persistence of specific paleoenvironmental conditions on the southern Neuquén Basin, at least during the Early-Late Cretaceous transition. Furthermore, this new evidence shows part of the faunal components of Lohancuran tetrapod assemblage, allowing new morphological and taxonomical comparisons with the saurian fauna of the upper section of Candeleros Formation. New data from the Lohan Cura and Candeleros formations will improve the knowledge about the diversification and the paleobiogeographical evolution of the saurian fauna during the Cretaceous of Neuquén Basin.