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Bite Force Estimation and the Fiber Architecture of Felid Masticatory Muscles
Article first published online: 15 JUN 2012
Copyright © 2012 Wiley Periodicals, Inc.
The Anatomical Record
Volume 295, Issue 8, pages 1336–1351, August 2012
How to Cite
Hartstone-Rose, A., Perry, J. M. G. and Morrow, C. J. (2012), Bite Force Estimation and the Fiber Architecture of Felid Masticatory Muscles. Anat Rec, 295: 1336–1351. doi: 10.1002/ar.22518
- Issue published online: 3 JUL 2012
- Article first published online: 15 JUN 2012
- Manuscript Accepted: 18 MAY 2012
- Manuscript Received: 21 NOV 2011
- bite force;
- fiber length;
- physiological cross-sectional area;
- muscle architecture
Increasingly, analyses of craniodental dietary adaptations take into account mechanical properties of foods. However, masticatory muscle fiber architecture has been described for relatively few lineages, even though an understanding of the scaling of this anatomy can yield important information about adaptations for stretch and strength in the masticatory system. Data on the mandibular adductors of 28 specimens from nine species of felids representing nearly the entire body size range of the family allow us to evaluate the influence of body size and diet on the masticatory apparatus within this lineage. Masticatory muscle masses scale isometrically, tending toward positive allometry, with body mass and jaw length. This allometry becomes significant when the independent variable is a geometric mean of cranial variables. For all three body size proxies, the physiological cross-sectional area and predicted bite forces scale with significant positive allometry. Average fiber lengths (FL) tend toward negative allometry though with wide confidence intervals resulting from substantial scatter. We believe that these FL residuals are affected by dietary signals within the sample; though the mechanical properties of felid diets are relatively similar across species, the most durophagous species in our sample (the jaguar) appears to have relatively higher force production capabilities. The more notable dietary trend in our sample is the relationship between FL and relative prey size: felid species that predominantly consume relatively small prey have short masticatory muscle fibers, and species that regularly consume relatively large prey have relatively long fibers. This suggests an adaptive signal related to gape. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.