Date of Graduation

5-2025

Document Type

Thesis

Degree Name

Bachelor of Science in Biology

Degree Level

Undergraduate

Department

Biological Sciences

Advisor/Mentor

Terhune, Claire

Committee Member

Alverson, Andrew

Second Committee Member

Beaulieu, Jeremy

Abstract

Antemortem tooth loss (AMTL) (i.e., defined as tooth loss occurring before death) is common among humans and many primates, and several studies have examined AMTL across various primate groups. Some research indicates that AMTL can influence masticatory function and diet; however, the effects of AMTL on craniofacial shape and biomechanics have not been extensively analyzed. We assessed craniofacial and mandibular shape in relation to AMTL, anticipating that individuals with at least one tooth lost antemortem would display significant differences in cranial and/or mandibular shape compared to those without AMTL. AMTL rates were evaluated in three primate species: wild-caught samples of Pan troglodytes (n=68) and Gorilla gorilla (n=85), as well as an archaeological sample of Homo sapiens (n=88) from Ancient Nubia. The prevalences of AMTL were initially compared among species and sexes using Fisher’s exact tests, followed by geometric morphometric techniques to measure craniofacial and mandibular shapes and compare individuals with and without AMTL within each species. Results reveal that humans exhibit the highest prevalence of AMTL, followed by chimpanzees and then gorillas. No sex differences were observed in AMTL prevalence for any species. The shape analyses further indicate that gorillas and humans (but not chimpanzees) with AMTL had significantly different mandible shapes; there was no effect of AMTL on cranial shape. This research has implications for comprehending the effects of AMTL on the skulls of both wild primates and modern humans, as well as how AMTL influences craniofacial shape and masticatory function.

Keywords

geometric morphometrics; tooth loss; cranial morphology; mandibular morphology

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