Comparative biomechanical analysis demonstrates functional convergence between slender-snouted crocodilians and phytosaurs

B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, Germany
School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
Department of Animal Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
School of Earth Sciences, University of Bristol, Bristol, United Kingdom
DOI
10.7287/peerj.preprints.27476v1
Subject Areas
Computational Biology, Evolutionary Studies, Paleontology
Keywords
Finite element analysis, Beam theory, Ebrachosuchus neukami, 3D visualisation
Copyright
© 2019 Lemanis et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Lemanis R, Jones AS, Butler RJ, Anderson PSL, Rayfield EJ. 2019. Comparative biomechanical analysis demonstrates functional convergence between slender-snouted crocodilians and phytosaurs. PeerJ Preprints 7:e27476v1

Abstract

Morphological similarities between the extinct Triassic archosauriform clade Phytosauria and extant crocodilians have formed the basis of long-proposed hypotheses of evolutionary convergence. These hypotheses have informed the reconstructions of phytosaur ecology and biology, including feeding preferences, body mass, soft tissue systems, mating behaviours, and environmental preferences. However, phytosaurs possess numerous cranial apomorphies that distinguish them from modern crocodilians and potentially limit ecomorphological comparisons. Here, we present the first computational mechanical comparison of phytosaur cranial strength to several extant crocodilian taxa using two biomechanical approaches: beam theory and finite element analysis. We demonstrate mechanical convergence between the slender-snouted phytosaur Ebrachosuchus neukami and modern slender-snouted crocodilians. We provide evidence that the phytosaurian premaxillary palate is functionally equivalent to the crocodilian secondary palate. The premaxillary palate is associated with greater resistance to biting induced stress, lower strain energy, higher resistance to bending and torsion, as well as increased performance under tension. In all tests, Ebrachosuchus performed worse than all tested crocodilians, showing higher stress under equivalent loading conditions. These findings have implications for the proposed feeding ecology of slender-snouted phytosaurs and corroborate previous broad assessments of phytosaur ecology based on morphological comparisons to crocodilians; however, we urge caution in overextending those assessments given the current paucity of comparative functional data.

Author Comment

This is a preprint submission to PeerJ Preprints

Supplemental Information

Von Mises Stress Values (MPa) for Three Biting Regimes

DOI: 10.7287/peerj.preprints.27476v1/supp-1

Maximum Principal Stress Values (MPa) for Three Biting Regimes

DOI: 10.7287/peerj.preprints.27476v1/supp-2