My Research

PhD Dissertation:
An assessment of the basihyal and its functional and ontogenetic relationships to the masticatory apparatus in primates

The hyoid bone plays a central role in feeding, vocalization, and breathing, yet it remains understudied in primates compared to other aspects of skull anatomy. My dissertation examined variation in primate hyoid morphology and its relationship with the mandible using microCT, diceCT, and 3D geometric morphometrics. Across a broad taxonomic sample, hyoid shape differs markedly between anthropoid and non-anthropoid primates, likely reflecting adaptations to different chewing and swallowing demands, and both hyoid shape and position scale with body size and jaw length. In a first for the literature, I demonstrated quantitatively that the hyoid and mandible significantly covary, suggesting functional integration during feeding. The suprahyoid muscles follow scaling patterns similar to the masticatory apparatus, where muscle mass scales with positive allometry and fiber length more negatively, yielding near-isometric physiological cross-sectional area. In ontogenetic comparisons between two capuchin species, Sapajus showed larger hyoids and more robust suprahyoid muscles than Cebus from the earliest developmental stages, yet only Cebus exhibited significant hyoid-mandible covariation, indicating that even closely related species can differ in how these structures are developmentally integrated. Together, these findings reveal that primate hyoid morphology reflects a complex interplay of phylogeny, size, biomechanical coordination, and development.