NEW DICRAEOSAURID (SAUROPODA) REMAINS FROM THE MULICHINCO FORMATION (VALANGINIAN, LOWER CRETACEOUS), NEUQUÉN BASIN, ARGENTINA

WINDHOLZ, G.J.; CORIA, R. A.; BAIANO, M.A.; BELLARDINI, F.; PINO, D.A.; CORIA, L.M.; GUTIERREZ, M.

Córdoba

Jornada; 33as Jornadas Argentinas de Paleontología de Vertebrados.; 2019

A.P.A.

New dicraeosaurid remains collected at the Pilmatué locality (Mulichinco Formation) comprise three articulated mid- to mid-posterior dorsal centra, and a complete right scapulo-coracoid. The centra are heavily eroded and transversely crashed. No pleurocoels are present, whereas in the most distal centrum a shallow lateral depression is present. The natural fractures show that the centra are massive internally, like the dorsal vertebrae of Pilmatueia faundeziCoria, Windholz, Ortega, Currie, 2019, and other dicraeosaurids. In contrast, the dorsal centra of non-dicraeosaurid diplodocoids and basal macronarians are pierced by foraminae, which communicate with the inside of the centra. In the scapula, the dorsal part of the posterior margin of the acromion process is slightly convex, and the distal end of the scapular blade is somewhat expanded, like other flagellicaudatans. The acromial process is placed proximally, above the glenoid position, like in Dicraeosaurus hansemanni Janensch, 1929; Amargasaurus cazaui Salgado and Bonaparte, 1991 and Suuwassea emilieae Harris and Dodson, 2004; and unlike non-dicraeosaurid diplodocoids where the acromial process is located nearly at the midpoint of scapular body. In the element described here, the angle between the acromion process and the coracoid is less than 90°, like in Amargasaurus cazaui. Preliminarily, these new materials are referred to Pilmatueia faundezi(come from the same site and geological formation) expanding the anatomical knowledge of this species.