New evidence of Ceratosaurus (Dinosauria: Theropoda) from the Late Jurassic of the Lusitanian Basin, Portugal

Abstract

A theropod assigned to Ceratosaurus was previously reported from the Portuguese Lusitanian Basin based on a limited number of elements of a single individual. Here, we describe newly discovered elements that likely pertain to same, earlier described, specimen. The new elements provide additional evidence that the range of Ceratosaurus spanned from what is now North America into Europe. Previously, some differences were noted between the Portuguese specimens and the North American Ceratosaurus. We consider these differences to be trivial and attribute them to individual variation and/or ontogeny. The following set of features (lesser trochanter positioned low on the femur; crista tibiofibularis obliquely oriented with respect to the axis of the femoral shaft; infrapopliteal ridge present posteriorly on the femur; large cnemial crest; and medial condyle of the tibia continuous with proximal end) indicate that the Portuguese specimen is assignable to Ceratosaurus. This record constitutes one of the scarce evidence of basal ceratosaurian theropods in the Late Jurassic of Europe. Despite the abundance, diversity and wide geographical distribution of ceratosaurs during the Late Cretaceous, its early evolutionary history remains poorly understood. The Portuguese specimens constitute an important evidence for the knowledge of the paleobiogeographic evolution of the clade during the Late Jurassic.

Keywords::

• Ceratosauria
• Lusitanian Basin
• Late Jurassic
• paleobiogeography

Acknowledgements

This research was conducted in Laboratório de Paleontologia e Paleoecologia, Sociedade de História Natural, Apartado 25, 2564–909 Torres Vedras, Portugal. We acknowledge J. Joaquim for field assistance; I. Gromicho for the illustrations of the bones; and L. Chiappe, L. Ivy, K. Carpenter, R. Scheetz, B. Britt, M. Getty, M. Loewen, R. Irmis, D. Chure, S. Chapman, P. Jeffery and R. Castanhinha for providing specimens during their institution's collections. We appreciate the comments of the two referees that have greatly improved the manuscript.

Notes

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Additional information

Funding

This work was supported by the Fundação para a Ciência e Tecnologia [grant number PTDC/CTE GEX/67723/2006], Jurassic Foundation, Fundação Luso-Americana para o Desenvolvimento [grant number L07-V-22/2010] and Synthesys [grant number GB-TAF-2160]; Câmara Municipal de Torres Vedras.