Complex Dental Structure and Wear Biomechanics in Non‐Avian Dinosaurs and Pleistocene Mammals

Abstract

Reptiles rarely approached the biomechanical sophistication for feeding or dietary diversity seen in mammals. Their teeth are typically non‐occluding, semi‐conical structures with simplistic parallel‐crystallite enamel surrounding an orthodentine core. Conversely, most mammals possess multi‐cusped teeth that are drawn across one another during mastication and self‐wear to their functional morphology. The most complex dental architectures are seen in herbivorous mammals. Their teeth are composed of up to four constituents (incl. prismatic enamel) that strategically wear creating coarse grinding or slicing surfaces. These allow them to comminute tough and/or abrasive plants and liberate nutrients inaccessible to other animals. Non‐avian dinosaurs stand out among reptiles in that precise, mammal‐like dental occlusion and self‐wearing teeth evolved on at least four occasions. These topographies enabled access to myriad floral types and facilitated their respective ecological diversifications. My research group and colleagues showed that the teeth of these dinosaurs are histologically more complex than formerly appreciated. Using cutting‐edge material science and tribological engineering indentation techniques we discovered that wear and fracture relevant material properties are preserved in the fossil dental tissues of dinosaurs and Pleistocene mammals. This led to development of a 3D Archard’s wear model from which we determined how horse‐like occlusal surfaces for the grinding of plant matter occurred in hadrosaurids, and fuller‐like slicing surfaces developed and functioned in ceratopsians. In current research we are studying how the grinding dentitions of mammoths similarly formed through self‐wear. Notably our paleontologically‐inspired wear model is seeing broad industrial applications.Support or Funding InformationNSF CMMI (Civil, Mechanical and Manufacturing Innovation) Eager and AFOSR (Air Force Office of Scientific Research) to GME, SP and BAK