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Evolutionary biomechanics: hard tissues and soft evidence?

Broyde, Sarah; Dempsey, Matthew; Wang, Linjie; Cox, Philip G.; Fagan, Michael; Bates, Karl T.


Sarah Broyde

Matthew Dempsey

Linjie Wang

Philip G. Cox

Michael Fagan

Karl T. Bates


Biomechanical modelling is a powerful tool for quantifying the evolution of functional performance in extinct animals to understand key anatomical innovations and selective pressures driving major evolutionary radiations. However, the fossil record is composed predominantly of hard parts, forcing palaeontologists to reconstruct soft tissue properties in such models. Rarely are these reconstruction approaches validated on extant animals, despite soft tissue properties being highly determinant of functional performance. The extent to which soft tissue reconstructions and biomechanical models accurately predict quantitative or even qualitative patterns in macroevolutionary studies is therefore unknown. Here, we modelled the masticatory system in extant rodents to objectively test the ability of current muscle reconstruction methods to correctly identify quantitative and qualitative differences between macroevolutionary morphotypes. Baseline models generated using measured soft tissue properties yielded differences in muscle proportions, bite force, and bone stress expected between extant sciuromorph, myomorph, and hystricomorph rodents. However, predictions from models generated using reconstruction methods typically used in fossil studies varied widely from high levels of quantitative accuracy to a failure to correctly capture even relative differences between macroevolutionary morphotypes. Our novel experiment emphasizes that correctly reconstructing even qualitative differences between taxa in a macroevolutionary radiation is challenging using current methods. Future studies of fossil taxa should incorporate systematic assessments of reconstruction error into their hypothesis testing and, moreover, seek to expand primary datasets on muscle properties in extant taxa to better inform soft tissue reconstructions in macroevolutionary studies.


Broyde, S., Dempsey, M., Wang, L., Cox, P. G., Fagan, M., & Bates, K. T. (2021). Evolutionary biomechanics: hard tissues and soft evidence?. Proceedings of the Royal Society B: Biological Sciences, 288(1945), Article 20202809.

Journal Article Type Article
Acceptance Date Jan 20, 2021
Online Publication Date Feb 17, 2021
Publication Date Feb 24, 2021
Deposit Date Feb 19, 2021
Publicly Available Date Feb 19, 2021
Journal Proceedings of the Royal Society B: Biological Sciences
Print ISSN 0962-8452
Electronic ISSN 1471-2954
Publisher The Royal Society
Peer Reviewed Peer Reviewed
Volume 288
Issue 1945
Article Number 20202809
Keywords Macroevolution; Rodent mastication; Biomechanics; Multi-body dynamics; Finite element analysis
Public URL


Published article (1.2 Mb)

Copyright Statement
© 2021 The Authors. Published by the Royal Society under the terms of the Creative Commons AttributionLicense, which permits unrestricted use, provided the original author and source are credited.

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