Meeting Abstract

142.5  Monday, Jan. 7  Complex Dental Structure and Wear Biomechanics in Hadrosaurid Dinosaurs ERICKSON, GM*; KRICK, BA; NORELL, MA; SAWYER, WG; Florida State Univ., Tallahassee; Univ. of Florida, Gainesville; American Museum of Natural History, New York; Univ. of Florida, Gainesville gerickson@bio.fsu.edu

Mammalian grinding dentitions are composed of four major tissues that differentially wear, creating coarse surfaces for pulverizing tough plants and liberating nutrients. Although such dentition evolved repeatedly in mammals (e.g. horses, bison, elephants), a similar innovation occurred much earlier (~85 ma) within the duck-billed dinosaur group Hadrosauridae, fueling their 35 million year occupation of Laurasian mega-herbivorous niches. How this complexity was achieved is unknown, as reptilian teeth are generally two-tissue structures presumably lacking biomechanical attributes for grinding. Here we show that hadrosaurids broke from the primitive reptilian archetype and evolved a six-tissue dental composition that is among the most sophisticated known. Three-dimensional wear models incorporating fossilized wear properties reveal how these tissues interacted for grinding and ecological specialization.