Brandon Truong
Research Mentor: Miriam Zelditch
Mentor Department: University of Michigan, LSA
Author(s): Brandon Truong, Miriam Zelditch, Donald Swiderski
Session: Session 6 (3:00 PM – 3:50 PM)
Presentation Type: Poster 82
Abstract
Tooth morphology in mammals reflects the mechanical demands of food processing, yet variation in tooth shape may be influenced by multiple factors beyond diet, including ecology, body size, and evolutionary history. Squirrels provide an ideal system for examining these relationships, as closely related species occupy diverse feeding niches ranging from nut and seed consumption to herbivory, grazing, and insectivory. This study investigates patterns of three-dimensional tooth shape variation among squirrel species and evaluates how these patterns correspond to dietary and ecological groupings. Tooth morphology is quantified using stereophotography to generate three-dimensional data from calibrated dual-camera setups. Anatomical landmarks and semi-landmarks are digitized from discrete features and along tooth curves using StereoMorph, enabling detailed characterization of complex tooth shapes. Geometric morphometric analyses are then used to compare shape variation among species, examine differences between tree and ground squirrels, and assess relationships among different functional regions of the tooth. Rather than testing a single diet-shape correspondence, this study focuses on identifying broader patterns of morphological variation and determining the extent to which tooth shape evolution aligns with diet, ecology, or other factors such as size. By emphasizing three-dimensional tooth morphology, this project builds on prior work focused on jaw shape and contributes to a more comprehensive understanding of how mammalian feeding structures evolve in response to multiple selective pressures. We expect that ground squirrels and tree squirrels will show measurable differences in molar morphology, reflecting dietary adaptations to different food sources such as harder seeds and nuts versus softer plant material.
