A THEROPOD DINOSAUR FROM THE LATE JURASSIC CAÑADÓN CALCÁREO FORMATION OF CENTRAL PATAGONIA, AND THE EVOLUTION OF THE THEROPOD TARSUS
Keywords:Theropoda, Tetanurae, Jurassic, Tarsals
AbstractA fragmentary postcranial skeleton from the Late Jurassic (Oxfordian–Tithonian) Cañadón Calcáreo Formation of Chubut, Argentina, represents a new taxon of theropod dinosaur, which is here described as Pandoravenator fernandezorum gen. et sp. nov. This material represents the first Late Jurassic theropod known from Argentina. Pandoravenator fernandezorum is characterized by strongly elongated postzygapophyses in the caudal vertebrae and an unusual tarsal joint, with the astragalus showing two distal tubercles and a very low and laterally inclined ascending process. Phylogenetic analyses indicate that the new taxon is a basal tetanuran, although its exact phylogenetic position within basal tetanurans remains uncertain, due to the fragmentary nature of the remains and the lack of consensus among the different phylogenetic analyses. The tarsus of P. fernandezorum shows an intermediate morphology between that of basal theropods and more derived tetanurans. It is especially noteworthy for the presence of a suture between the distal astragalar condyles and the anteroproximal extension of the astragalus, including the ascending process. This indicates that a separate ossification of the ascending process of the astragalus was present in this taxon, and, in a phylogenetic context, thus provides evidence that the origin of the ascending process and the astragalar body from separate ossifications was already present at the base of Averostra.
How to Cite
Authors publishing in Ameghiniana have the option of making their article freely available online. Authors opting for the Open Access must pay a fee of $300 (US dollars) to cover article-processing costs and to ensure the article is made open access. Please contact the Production Team after the acceptance of your manuscript if you are interested in making your article Open Access. This option implies by default a license Creative Commons Attribution Non-Commercial-NoDerivs License (CC BY NC ND). If your funding institution requires a different licensing option please communicate this to the Production Team after the acceptance of your manusctipt.