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Regional patterning in tail vertebral form and function in chameleons (Chamaeleo calyptratus)

Luger, Allison M.; Watson, Peter J.; Dutel, Hugo; Fagan, Michael J.; Van Hoorebeke, Luc; Herrel, Anthony; Adriaens, Dominique


Allison M. Luger

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Dr Peter Watson
Senior Lecturer in Mechanical Engineering

Hugo Dutel

Michael J. Fagan

Luc Van Hoorebeke

Anthony Herrel

Dominique Adriaens


Previous studies have focused on documenting shape variation in the caudal vertebrae in chameleons underlying prehensile tail function. The goal of this study was to test the impact of this variation on tail function using multibody dynamic analysis (MDA). First, observations from dissections and 3D reconstructions generated from contrast-enhanced µCT scans were used to document regional variation in arrangement of the caudal muscles along the antero-posterior axis. Using MDA, we then tested the effect of vertebral shape geometry on biomechanical function. To address this question, four different MDA models were built: those with a distal vertebral shape and with either a distal or proximal musculature, and reciprocally the proximal vertebral shape with either the proximal or distal musculature. For each muscle configuration, we calculated the force required in each muscle group for the muscle force to balance an arbitrary external force applied to the model. The results showed that the models with a distal-type of musculature are the most efficient, regardless of vertebral shape. Our models also showed that the m. ilio-caudalis pars dorsalis is least efficient when combining the proximal vertebral shape and distal musculature, highlighting the importance of the length of the transverse process in combination with the lever-moment arm onto which muscle force is exerted. This initial model inevitably has a number of simplifications and assumptions, however its purpose is not to predict in vivo forces, but instead reveals the importance of vertebral shape and muscular arrangement on the total force the tail can generate, thus providing a better understanding of the biomechanical significance of the regional variations on tail grasping performance in chameleons.


Luger, A. M., Watson, P. J., Dutel, H., Fagan, M. J., Van Hoorebeke, L., Herrel, A., & Adriaens, D. (2021). Regional patterning in tail vertebral form and function in chameleons (Chamaeleo calyptratus). Integrative and Comparative Biology, 61(2), 455-463.

Journal Article Type Article
Acceptance Date Jun 8, 2021
Online Publication Date Jun 10, 2021
Publication Date Sep 8, 2021
Deposit Date Jul 26, 2021
Publicly Available Date Oct 27, 2022
Journal Integrative and comparative biology
Print ISSN 1540-7063
Electronic ISSN 1557-7023
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 61
Issue 2
Article Number icab125
Pages 455-463
Keywords Plant Science; Animal Science and Zoology
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Copyright Statement
© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology.

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