NEW SAUROPOD INFORMATION FROM ?VALLE DE LOS TITANOS? SITE, CAMPANIAN (UPPER CRETACEOUS), NEUQUÉN BASIN, PATAGONIA, ARGENTINA

BELLARDINI, FLAVIO; WINDHOLZ, G.J.; BAIANO, M.A.; GARRIDO, A.C.; LECUONA, A; POL, DIEGO

Villa El Chocón

Jornada; https://www.peapaleontologica.org.ar/index.php/peapa/article/view/416/710; 2021

MMCH-APA-CONICET

The fieldworks carried out by an italo-argentinian paleontological team to the ?Valle de los Titanos? (General Roca, Río Negro Province, Argentina) discovered several fossiliferous sites in the fluvial outcrops that we preliminarily refer to the lower section of Allen Formation (Campanian). From 2005 to 2010, more than five hundred sauropod bones were recovered from a single fossiliferous layer and housed in the Museo Patagónico de Ciencias Naturales of General Roca. Our preliminary osteological examination of the material from the site ?G? and ?L?, two quarries at 150 m apart each other, allows us to recognize cranial, axial, and appendicular elements of several titanosaurian specimens at different ontogenetic stages. The caudal vertebrae are procoelic and high pneumatized, like seen in Rocasaurus, but lack of the longitudinal septum on ventral surfaces. The scapula MPCN-PV-407 from the site ?G? have a quadrangular acromion process and a posteriorly unexpanded shaft; anteroventrally, the glenoid is medially beveled and strongly ventrally expanded, forming a prominent process, which is absent in the scapula MPCN-PV-243.45 from site ?L? and in any other sauropod known. A fibula from site ?G? (MCPC-PV-242.1) bears a mediodistal fossa, as in Saltasaurus, but it is absent in a fibula from site ?L? (MPCN-PV-243.85). This preliminary analysis suggests the co-existence of at least two titanosaurian morphotypes in the ?Valle de los Titanos? area. Further comparisons with the others titanosaurian taxa from the Allen Formation will allow us to elucidate the composition of the sauropod fauna in the southeast Neuquén Basin during the middle?late Campanian.SESIONES LIBRES