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. 2022 Jul 12:10:e13731.
doi: 10.7717/peerj.13731. eCollection 2022.

Estimating bite force in extinct dinosaurs using phylogenetically predicted physiological cross-sectional areas of jaw adductor muscles

Manabu Sakamoto  1
Affiliations

Estimating bite force in extinct dinosaurs using phylogenetically predicted physiological cross-sectional areas of jaw adductor muscles

Manabu Sakamoto. PeerJ. .

Abstract

I present a Bayesian phylogenetic predictive modelling (PPM) framework that allows the prediction of muscle parameters (physiological cross-sectional area, A Phys) in extinct archosaurs from skull width (W Sk) and phylogeny. This approach is robust to phylogenetic uncertainty and highly versatile given its ability to base predictions on simple, readily available predictor variables. The PPM presented here has high prediction accuracy (up to 95%), with downstream biomechanical modelling yielding bite force estimates that are in line with previous estimates based on muscle parameters from reconstructed muscles. This approach does not replace muscle reconstructions but one that provides a powerful means to predict A Phys from skull geometry and phylogeny to the same level of accuracy as that measured from reconstructed muscles in species for which soft tissue data are unavailable or difficult to obtain.

Keywords: Biomechanics; Bite force; Dinosaurs; Phylogenetic comparative methods; Phylogenetic predictive modelling; Physiological cross-sectional area.

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Conflict of interest statement

The author declares that he has no competing interests.

Figures

Figure 1
Figure 1. Jaw adductor muscles and functional muscle groupings in extant archosaurs.
(A) Attachment sites for jaw adductor muscles are depicted on a skull of a herring gull (Larus fuscus). Abbreviations are as follows: mAME, M. adductor mandibulae externus; mPSTs, M. pseudotemporalis superficialis; mPSTp, M. pseudotemporalis profundus; mAMP, M. adductor mandibulae posterior; and mPT, M. pterygoideus. Adductor muscle anatomy is then depicted for: (B) all adductor muscles; (C) temporal muscle group (mAME + mPSTs); (D) the quadrate muscle group (mPSTp + mAMP); and (E) the pterygoid muscle group (mPT).
Figure 2
Figure 2. Relationships between physiological cross-sectional areas and skull width in the PPM training set (N = 59).
Relationships between physiological cross-sectional areas APhys for each of the three muscle groups and skull width (WSk) are shown for extant (blue) and extinct (red) archosaurs in the PPM training set (N = 59): (A) temporal muscle group (mTemp); (B) quadrate muscle group (mQuad); and (C) pterygoid muscle group (mPt).
Figure 3
Figure 3. Phylogeny of extant and extinct saurians (N = 59) used in the phylogenetic predictive modelling.
The extant portion of the tree was taken from the TimeTree of Life and extinct tips inserted at the relevant positions.
Figure 4
Figure 4. Schematic depiction of a static lever model to estimate bite force in extinct dinosaurs.
Bite force (FBAnt and FBPost) was estimated in extinct dinosaurs using a static lever model as shown on a skull and mandible reconstruction of Deinonychus (author’s own work). FBAnt, anterior bite force; FBPost, posterior bite force; FTemp, temporal group muscle force; FQuad, quadrate group muscle force; FPt, pterygoid group muscle force.
Figure 5
Figure 5. Relationship between bite force and skull width.
The relationship between bite force and skull width is shown for estimates based on predicted APhys (light green) and those based on muscle reconstructions (pink).
See this image and copyright information in PMC

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Grants and funding

The author received no funding for this work.

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