DICRAEOSAURID TEETH FROM THE MULICHINCO FORMATION (VALANGINIAN, LOWER CRETACEOUS), NEUQUÉN, ARGENTINA

WINDHOLZ, G.J.; BAIANO, M.A.; MESO, J.G.

Corrientes

Congreso; XXXII Jornadas Argentinas de Paleontología de Vertebrados; 2019

Asociación Paleontológica Argentina

Available information about dental morphology of dicraeosaurid sauropods is scarce worldwide, only known from the Upper Jurassic Dicraeosaurus Janensch, 1914 and Suuwassea Harris and Dodson, 2004; and isolated teeth from the Lower Cretaceous putatively referred to Amargasaurus Salgado and Bonaparte, 1991. Here we report three teeth collected associated with a partially articulated dicraeosaurid skeleton from the Mulichinco Formation (Valanginian, Lower Cretaceous) in the locality Pilmatué, Neuquén province. The general morphology of the teeth indicates affinities with Diplodocoidea, based on a cylindrical middle crown, with a sub-circular cross section. Unfortunately the teeth lack the typical wear facet, precluding a comparison with other diplodocoids, dicraeosaurid, or even titanosaurian teeth. However, the specimens here described differ from rebbachisaurid teeth due to the oval shape in cross section from the middle crown to the apex. The crown here described lack of longitudinal grooves on the lingual aspect of the teeth, as in other Flagellicaudata teeth. The enamel is asymmetric, forming a thicker labial layer, like in Diplodocus Marsh 1878 and Dicraeosaurus. The specimens show an overallresemblance to Dicraeosaurus teeth, based on the curvature of the element and the presence of lateral crests in the crown. These materials plus those communicated in previous meetings from Bajada Colorada Formation represent the oldest dicraeosaurid teeth recorded in the Cretaceous, and provide new morphological information about the dental morphology of this emblematic sauropod group.