1Department of Anthropology, Northeastern Illinois University, 2Department of Community and Family Medicine, Duke University School of Medicine
Thursday Morning, 301D
Cranial and temporomandibular joint (TMJ) form have been shown to reflect masticatory forces and mandibular range of motion, which vary in relation to feeding strategy. Similarly, the dentition, as the portion of the masticatory apparatus most directly involved in triturating food items, strongly reflects dietary profile. Fine control over condylar and mandibular movements guides the teeth into occlusion, while the topography and position of the dental arcade mediate mandibular movements. Thus, we hypothesize that masticatory, and particularly TMJ, morphology and dental form covary in predictable ways with primate diet. We employed three-dimensional geometric morphometric techniques to examine both intra- and inter-specific variation in ten platyrrhine species. Landmarks were collected on six separate datasets describing the upper and lower molars, the cranium, glenoid fossa, mandible, and mandibular condyle; 2B-PLS analyses were performed to assess co-variation between cranial morphology and the dentition. Significant relationships were identified between the upper and lower molars and the mandible, and between the upper and lower molars and the glenoid fossa. Some of these shape complexes reflect feeding strategy; for example, higher crowned/cusped dentitions, as found in primates consuming larger quantities of structural carbohydrates (e.g., Alouatta and Saimiri), correspond to deeper glenoid fossae and larger post-glenoid processes. These results indicate strong covariance between dental and TMJ form, aspects of which are related to feeding behavior. However, other aspects of morphological variation display a strong phylogenetic signal; we must therefore examine further ways in which to control for phylogeny when examining covariation of interspecific masticatory form.
Grant support for this project was provided by NSF DDIG 40761-0001 (SBC); Alumnae Association ofBarnard College Graduate fellowship (SBC); NSF BCS 0752661 (CET); The Leakey Foundation (CET).