Presenter: Eva Biedron
Mentor: Samantha Hopkins
Poster: 4
Major: Geology/Biology
Morphological convergence among rodents living in similar habitats is common and well recorded. While upper incisor angle has been studied in connection with diet, lower incisor angle has been relatively neglected, despite textbook assertions that it correlates to habitat. Due to the difference in diets and jaw use between the terrestrial tribe Marmotini and the arboreal tribe Sciurini, it is expected that the tribes will display different mandible morphology, specifically lower incisor angle and diastema depth. The inclination of the lower incisor was quantified by measuring its angle relative to the occlusal surface of the lower molars with the mandible in lateral view. Diastema depth was measured as a vertical line along the anterior edge of the mental foramina, again viewing the mandible laterally. Preliminary data supports a relationship between smaller lower incisor angles and arboreality (t22 = 2.652, p = 0.015), but does not support diastema depth (t12 = 0.375, p = 0.714) as a predictor of arboreality. Changing habitats during the early Oligocene could have prompted the radial evolution of sciurids; by understanding how modern squirrels’ morphology is related to the habitat they live in, paleontologists will be able to better reconstruct a fossil squirrel’s paleoenvironment by using measurements of commonly preserved cranial elements as a proxy for actual habitat data.