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Erlikosaurus (Therizinosauria) cranial anatomy (free pdf)

Ben Creisler

In the new issue of JVP--pdf is in open access:

Stephan Lautenschlager, Lawrence M. Witmer, Perle Altangerel, Lindsay
E. Zanno & Emily J. Rayfield (2014)
Cranial anatomy of Erlikosaurus andrewsi (Dinosauria,
Therizinosauria): new insights based on digital reconstruction.
Journal of Vertebrate Paleontology 34(6): 1263-1291

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.


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