Osteology of the Patagonian ornithopod Talenkauen santacrucensis (Dinosauria, Ornithischia)

Abstract

Talenkauen santacrucensis represents one of the most complete South American ornithopods yet discovered. This dinosaur comes from the Mata Amarilla Formation (Turonian) of Santa Cruz Province, Argentina. The aim of this contribution is to present a detailed description of Talenkauen santacrucensis. Features of the cervical series of Talenkauen, which are shared with other elasmarians, indicate that these dinosaurs have a proportionally longer neck than other ornithopods. These traits were convergently acquired by several saurischian clades. Additionally, some features, including an ornamented labial surface of the mandibular teeth and a sigmoidal greater trochanter of femur, are traits shared by most elasmarians, and may prove to be synapomorphies of this clade. A phylogenetic analysis recovers most Cretaceous Gondwanan ornithopods in the clade Elasmaria. This analysis indicates that Elasmaria was distributed more widely geographically and temporally than previously thought.

Keywords:

• Ornithopoda
• Euiguanodontia
• Elasmaria
• Talenkauen santacrucensis
• Gondwana
• Patagonia

Acknowledgements

We thank our laboratory co-workers Alexis. M. Aranciaga-Rolando, Matías J. Motta, Adriel R. Gentil, Martín D. Ezcurra, Nicolás R. Chimento, Federico Brison-Egli and Julieta Vigliano-Relva for their comments and observations during the writing of the present contribution. Special regards to Susan Gowland for assistance with English. We also thank Marcelo Reguero, who kindly allowed us to review the Trinisaura holotype, and Penélope Cruzado-Caballero, who provided Macrogryphosaurus photographs. Special thanks to Matthew G. Baron, Susannah C. R. Maidment and Paul M. Barrett for their helpful and enlightening comments that notably improved the quality of the manuscript.

Supplemental material

Supplemental material for this article can be accessed here: http://dx.doi.org/10.1080/14772019.2019.1582562.

Associate Editor: Susannah Maidment