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Biomechanics of Dromaeosaurid Dinosaur Claws: Application of X-Ray Microtomography, Nanoindentation, and Finite Element Analysis
Article first published online: 26 AUG 2009
Copyright © 2009 Wiley-Liss, Inc.
The Anatomical Record
Special Issue: Unearthing the Anatomy of Dinosaurs: New Insights Into Their Functional Morphology and Paleobiology
Volume 292, Issue 9, pages 1397–1405, September 2009
How to Cite
Manning, P. L., Margetts, L., Johnson, M. R., Withers, P. J., Sellers, W. I., Falkingham, P. L., Mummery, P. M., Barrett, P. M. and Raymont, D. R. (2009), Biomechanics of Dromaeosaurid Dinosaur Claws: Application of X-Ray Microtomography, Nanoindentation, and Finite Element Analysis. Anat Rec, 292: 1397–1405. doi: 10.1002/ar.20986
- Issue published online: 26 AUG 2009
- Article first published online: 26 AUG 2009
- Manuscript Received: 9 JUN 2009
- Manuscript Accepted: 9 JUN 2009
- Engineering and Physical Sciences Research Council in the United Kingdom (finite element modeling). Grant Numbers: EP/F055595/1, EP/D037867/1
- finite element analysis
Dromaeosaurid theropod dinosaurs, such as Velociraptor, possess strongly recurved, hypertrophied and hyperextensible ungual claws on the pes (digit II) and manus. The morphology of these unguals has been linked to the capture and despatching of prey. However, the mechanical properties or, more importantly, the mechanical potential of these structures have not been explored. Generation of a 3D finite element (FE) stress/strain contour map of a Velociraptor manual ungual has allowed us to evaluate quantitatively the mechanical behavior of a dromaeosaurid claw for the first time. An X-ray microtomography scan allowed construction of an accurate 3D FE mesh. Analogue material from an extant avian theropod, the pedal digit and claw of an eagle owl (Bubo bubo), was analyzed to provide input data for the Velociraptor claw FE model (FEM). The resultant FEM confirms that dromaeosaurid claws were well-adapted for climbing as they would have been resistant to forces acting in a single (longitudinal) plane, in this case due to gravity. However, the strength of the unguals was limited with respect to forces acting tangential to the long-axis of the claw. The tip of the claw functioned as the puncturing and gripping element of the structure, whereas the expanded proximal portion transferred the load stress through the trabeculae and cortical bone. Enhanced climbing abilities of dromaeosaurid dinosaurs supports a scansorial phase in the evolution of flight. Anat Rec, 292:1397–1405, 2009. © 2009 Wiley-Liss, Inc.