Date Approved

12-2018

Graduate Degree Type

Thesis

Degree Name

Health Sciences (M.H.S.)

Degree Program

Biomedical Sciences

First Advisor

Melissa Tallman

Second Advisor

Laura Stroik

Third Advisor

Claire Terhune

Academic Year

2018/2019

Abstract

Many studies have focused on the soft tissue analysis of carnivores and have demonstrated a relationship between feeding biomechanics and feeding types. Herbivores and omnivores rely heavily on anteroposterior and helical movement of the mandible and teeth for the breakdown of fibrous foods resulting in a flat mandibular fossa while the function of the carnivore TMJ is different, as they need a much stable joint for ripping and tearing of the flesh. I aim to look at whether the bony morphology of the temporomandibular joint (TMJ) can be directly related to feeding type, specifically in the superfamily Musteloidea. I sampled the complete TMJ of Gulo gulo, Lontra canadensis, Potos flavus, and Procyon lotor, a dietarily diverse selection of musteloid carnivorans. I used three-dimensional scans of specimens and evaluated them by use of principal component analysis (PCA) and phylogenetic principal component analysis (pPCA) to look for data that correlated feeding type and TMJ morphology. The resulting PCA and pPCA data indicates that the feeding type is only one influential piece of bony TMJ morphology and other characteristics including locomotor habitat, soft tissue dependencies, and other non-TMJ bony characteristics contribute to the masticatory apparatus and feeding biomechanics of the TMJ. Specifically, characteristics such as snout length, coronoid process angulation, tubercle positionings, and fossa shapes, sizes, and orientations all influence TMJ morphology.

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