Biomechanical form and function in primate seed predators : common solutions for similar mechanical challenges?

Hunter, Emily M.

Abstract

Seed predation, as seen in a diverse range of primate species, is a specialist diet in which seeds are accessed via the breakdown of stress-resistant external protective layers. This diet is considered mechanically challenging, requiring high forces and wide gapes to successfully fracture seed casings and gain access to nutrients. It is expected that seed predators will possess anatomical features which facilitate the breakdown of large, hard items. The biomechanical function of seed predator morphology relative to other primates is not known, nor is it known if members of this group converge on the same morphologies. This study examines the masticatory morphology of a diverse range of primate seed predators by combining 1) geometric morphometrics and convergence testing, 2) biomechanical modelling and 3) direct physical testing of tooth performance.
Comparisons between different seed predator masticatory morphologies demonstrate some convergence in shape, but other factors including body size, prognathism, and dental morphology appear to enable different solutions to the same mechanical problem. Smaller-bodied seed-predators primarily show adaptations for high mechanical advantage, while larger-bodied seed predators have large muscle cross-sectional area but low mechanical advantage. The dentition of some seed predators requires less force to fracture hard brittle seeds than non-seed predators. Surprisingly, some non-seed predators also possess features which are advantageous to hard food consumption, while one intensive seed predator has poor performance on nearly all measurements.
This study suggests no common solution for seed predation, but instead proposes multiple morphologies capable of meeting the demands of this diet. Results presented here also highlight the need to consider the masticatory system as a whole, as both muscle force capacity and dental occlusal surface impact food breakdown. Without considering these different components of the masticatory apparatus it is not possible to fully appreciate the potential for functional equivalence in this system.

Citation

Hunter, E. M. Biomechanical form and function in primate seed predators : common solutions for similar mechanical challenges?. (Thesis). Hull York Medical School, the University of Hull and the University of York. https://hull-repository.worktribe.com/output/4223650

• Thesis Type: Thesis
• Deposit Date: Nov 24, 2021
• Publicly Available Date: Feb 24, 2023
• Keywords: Medicine
• Public URL: https://hull-repository.worktribe.com/output/4223650
• Additional Information: Hull York Medical School, The University of Hull and the University of York
• Award Date: Mar 1, 2021