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1 November 2014 Cranial Anatomy of Erlikosaurus andrewsi (Dinosauria, Therizinosauria): New Insights Based on Digital Reconstruction
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The skull of Erlikosaurus andrewsi from the Upper Cretaceous Baishin Tsav locality of Mongolia represents the only known three-dimensionally preserved and nearly complete skull of a therizinosaurian. Computed tomographic (CT) scanning of the original specimen and three-dimensional visualization techniques allow the cranial skeleton to be digitally prepared, disarticulated, and restored. Here, we present a detailed description of the restored skull morphology and the individual cranial elements, including visualization of the internal neurovascular and pneumatic structures. Information gained from this study is used in a revised and emended diagnosis for E. andrewsi. A reappraisal of the evolutionary and functional changes in the cranial skeleton as provided by this study supports prior proposals that a keratinous sheath or rhamphotheca was developed early in the evolution of Therizinosauria. Paralleled by the reduction of functional and replacement teeth, this development indicates a shift in the manner of food processing/procurement at the tip of the snout. Extensive pneumatization of the braincase, most evidently developed in E. andrewsi in comparison with other known therizinosaurians, appears to have led to a reduction of the adductor musculature and thus the potential bite force in derived therizinosaurians. In addition, the application of digital data, as presented in this study, introduces a novel way to document fossil data that will allow for morphological and anatomical data to be made widely accessible.

© 2014 by the Society of Vertebrate Paleontology
Stephan Lautenschlager, Lawrence M. Witmer, Perle Altangerel, Lindsay E. Zanno, and Emily J. Rayfield "Cranial Anatomy of Erlikosaurus andrewsi (Dinosauria, Therizinosauria): New Insights Based on Digital Reconstruction," Journal of Vertebrate Paleontology 34(6), 1263-1291, (1 November 2014).
Received: 3 August 2013; Accepted: 1 December 2013; Published: 1 November 2014

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