NEW TITANOSAUR RECORD FROM THE UNIVERSIDAD NACIONAL DEL COMAHUE CAMPUS OF NEUQUÉN CITY (PATAGONIA, ARGENTINA)

PORFIRI, JUAN; VALIERI JUAREZ, RUBEN; GARRIDO, A.C.; BELLARDINI, F.; DINIZ DOS SANTOS, DOMENICA

Neuquén

Jornada; 2DAS JORNADAS DE PALEOVERTEBRADOS DE LA CUENCA NEUQUINA; 2022

UNCO-APA-Ministerio Culturas Neuquén

The campus of the Universidad Nacional del Comahue is known for the diverse fauna of small-sized tetrapods that comefrom the top of the Bajo de la Carpa Formation, however the record of larger dinosaurs is scarce. Here we report a right ulnareferred to middle-sized sauropod (MUCPv-1558) that was recently founded in the base of the Anacleto Formation(Neuquén Group: Late Cretaceous). The element is almost complete, only lacking the proximal anterolateral process. Thelength of the bone is 585 mm, with a robust index barely exceeding 0.4. In antero-posterior view, the olecranon process isvery low, opposite to the condition of most titanosaurs, and the anteromedial process bears a flat articular surface. Thedistal end is poorly expanded, while the articular surface is subtriangular in-shape in distal view. Several of these charactersare shared with different titanosaur taxa, but the combination of characters seen in MUCPv-1558 is shared with Bonitasaura salgadoi Apesteguía, which comes from equivalent levels of La Bonita locality, Río Negro Province. Additionally, MUCPv-1558 shares with B. salgadoi ulna the distal end morphology, with a concave anteromedial face and a convex posterior face,as well as the development of muscle scar on the anterior face. Although the ulnae are preserved in several titanosaurtaxa, this appendicular element is poorly considered in the phylogenetic analysis for bears scarce diagnostic features. Herewe refer preliminarly MUCPv-1558 to cf. Bonitasaura, which allows to increase the sauropod fossil record in thesoutheastern Neuquén basin.