The Functional Morphology of Hard-Prey Crushing Teeth
Crofts, Stephanie B.
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Durophagy is the consumption of hard-shelled prey-items, like shelled molluscs and crustaceans with hard exoskeletons. In order to break these hard shells, organisms need to be able to generate large bite-forces, which are transferred to the prey via the teeth. As such, the teeth of durophagous predators are specialized, and are typically described as “flattened,” “molariform,” “pavement-like,” “pebble-like,” or “hemispherical.” But these descriptors do not accurately reflect the diversity of tooth morphologies seen in hard-prey specialists. Teeth can vary in occlusal convexity from highly domed to flat, but may also be concave, and some even have small cusps, presumably to concentrate stress applied to their prey. This variation in morphology indicates that there should also be variation in tooth function, but little experimental work has been done on the function of durophagous teeth. The goals of this thesis are fourfold: 1) To use canonical models of durophagous teeth to test how much force different occlusal morphologies require to break prey items; 2) To use finite element models of the same set of canonical teeth to test how these different morphologies are able to disperse and distribute in-tooth strain and resist failure; 3) To use these two studies to identify functional trade-offs and predict a theoretical optimal tooth; 4) To use the extinct clade of marine reptiles, the Placodontia, as a case study to see if functional trade-offs can allow us to predict durophagous tooth morphologies, and to determine what other factors may be in play.
- Biology