Meeting Abstract

P3.98  Friday, Jan. 6  Effects of morphology on the function of crushing teeth CROFTS, SB; University of Washington

One of the diagnostic features of durophagous organisms are their teeth, which are generally described as low, robust, domes. A number of lineages of non-mammalian organisms include hard-prey specialists, and there is a wide diversity of tooth forms represented by these different groups. Teeth range from conical, to flat, and even to cupped shapes. The occlusal surface of a tooth may be smooth, or it may have force-concentrating projections. Are these different tooth shapes specialized for breaking different prey items? Why are some tooth-forms more common than others, and are there functional draw-backs to extreme forms? Or, are there trade-offs between tooth function and structural integrity? It has been proposed that the generalized molariform tooth shape associated with durophagy is an adaptation to either increased crushing efficiency, or increased resistance to breakage. To test the ability of different tooth shapes to crush prey items, we constructed three series of simplified tooth models that graded from one morphological extreme to another. We varied the degree of convexity/concavity of the occlusal surface, the height of a small conical stress concentrator, and the radius of a centrally located stress concentrator. In a materials testing system, we tested the ability of these tooth shapes to crush morphologically and compositionally identical prey items, in order to determine the relationships of the different morphologies. We compared these results to a previous study on the finite element analysis of these same tooth shapes to determine whether prey-breaking or the prevention of tooth breakage plays a more important role in the evolution of tooth shape.