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| Azhdarchid pterosaur in Williams, Pani, Bucchi, ... et Martill, 2021. Illustration: Davide Bonadonna |
Highlights
• Trabeculae in a pterosaur cervical vertebra are helically arranged.
• As few as 50 trabeculae increase the buckling load by up to 90%.
• Subsuming the neural tube into the centrum adds stiffness to the cervical series.
Summary
Azhdarchid pterosaurs, the largest flying vertebrates, remain poorly understood, with fundamental aspects of their palaeobiology unknown. X-ray computed tomography reveals a complex internal micro-architecture for three-dimensionally preserved, hyper-elongate cervical vertebrae of the Cretaceous azhdarchid pterosaur, Alanqa sp. Incorporation of the neural canal within the body of the vertebra and elongation of the centrum result in a “tube within a tube” supported by helically distributed trabeculae. Linear elastic static analysis and linearized buckling analysis, accompanied with a finite element model, reveal that as few as 50 trabeculae increase the buckling load by up to 90%, implying that a vertebra without the trabeculae is more prone to elastic instability due to axial loads. Subsuming the neural tube into the centrum tube adds considerable stiffness to the cervical series, permitting the uptake of heavy prey items without risking damage to the cervical series, while at the same time allowing considerable skeletal mass reduction.
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| Cervical vertebra of Alanqa sp. from the Kem Kem Group of Morocco |
Cariad J. Williams, Martino Pani, Andrea Bucchi, Roy E. Smith, Alexander Kao, William Keeble, Nizar Ibrahim and David M. Martill. 2021. Helically arranged cross struts in Azhdarchid Pterosaur Cervical Vertebrae and their Biomechanical Implications. iScience. DOI: 10.1016/j.isci.2021.102338
