A sauropodomorph tooth increases the diversity of dental morphotypes in the Cañadón Asfalto Formation (Early?Middle Jurassic) of Patagonia.

Abstract

This communication aims to describe an isolated sauropodomorph tooth (MPEF-PV10860) from the Cañadón Asfalto Formation and test its phylogenetic relationships with other sauropodomophs. The novelty of this specimen implies a combination of features present in non-sauropod sauropodomorphs (coarse denticles at 45° with respect to the margin, absent marginal grooves and lingual concavity) and others previously referred as synapomorphic of Sauropoda and subgroups of this lineage (D-shaped cross section, enamel wrinkling). Acomparison with formerly defined sauropod tooth morphotypes from Cañadón Asfaltohighlights major differences in enamel wrinkling, having a simpler and more homogeneous pattern. The crown proportions, compared with other sauropodomorph teeth, retrieves MPEFPV 10860 within the morphospace of sauropods in two different age-ratio scatterplots, and the phylogenetic analysis depicts this specimen in multiple positions within Sauropodiformes but outside Eusauropoda, indicating the presence of both eusauropods and non-eusauropods in the Cañadón Asfalto Formation, being a putative new species.