Meeting Abstract

S3-3  Saturday, Jan. 4 09:00 - 09:30  What is homodonty? COHEN, K.E*; WELLER, H.I; SUMMERS, A.P; University of Washington ; Brown University ; University of Washington

Homodonty and heterodonty attempt to capture tooth battery morphology as it relates to prey processing. Homodont teeth are similar in shape or size and assumed to perform a uniform task. Heterodont teeth have shape regionalization and are associated with regionalized functions. These categories have poorly defined boundaries: how much morphological variation is permitted in a homodont dentition before it should be classified as heterodont? Development, replacement, and damage directly alter the shape and size of teeth along the jaw further complicating homodonty. Incipient, transient, or phylogenetic homodonty attempt to provide a more rigorous definition by incorporating additional contingencies, but instead serve to highlight the difficulties in categorizing dentitions. For instance, conical teeth are a simple shape with a simple job of puncture. Yet they vary in length, curvature, and sharpness as a result of additional selective pressures aside from puncture. By constraining homodonty to static shape, we miss aspects of how teeth are being used. Instead we propose to use function to tease apart not just how teeth look, but how they are used. We present a functional lens on homodonty by looking at stress, orientation, and curvature. These functional parameters allow us to analyse how large and small teeth work together to transmit forces to a prey item. Our results show that the placement of teeth affects their function and that there is a functional advantage to having several smaller teeth surrounding a singular large tooth. Our statistical models present a new tool for determining ‘functional homodonty’ and a series of dentitions that demonstrate the complexities of this problem. We show that teeth that look alike don't always act alike; morphologically heterodont teeth are functionally homodont.