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Re: [dinosaur] Azhdarchid cervical vertebrae with helical cross struts for strength (free pdf)




News:

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Gigantic flying pterosaurs had spoked vertebrae to support their 'ridiculously long' necks

https://phys.org/news/2021-04-gigantic-pterosaurs-spoked-vertebrae-ridiculously.html

https://www.theguardian.com/science/2021/apr/14/flying-giant-pterosaurs-long-necks-experts

https://www.sciencemag.org/news/2021/04/pterosaur-supported-its-giant-neck-bones-built-bicycle-wheels

https://www.nytimes.com/2021/04/14/science/pterosaurs-necks-azhdarchids.html


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On Wed, Apr 14, 2021 at 9:18 AM Ben Creisler <bcreisler@gmail.com> wrote:

Ben Creisler
bcreisler@gmail.com

A new paper with free pdf:


Free pdf:

Cariad J. Williams, Martino Pani, Andrea Bucchi, Roy E. Smith, Alexander Kao, William Keeble, Nizar Ibrahim & David M. Martill (2021)
Helically arranged cross struts in azhdarchid pterosaur cervical vertebrae and their biomechanical implications.
iScience 102338
doi: https://doi.org/10.1016/j.isci.2021.102338
https://www.sciencedirect.com/science/article/pii/S2589004221003060

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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