Gregory M. Erickson and Mark A. Norell Throughout their 300+ million year history, herbivorous reptiles rarely acquired teeth that allowed for chewing in the manner of ungulate mammals (e.g. horses and cows). The lone exception was the duck-billed dinosaurs (aka hadrosaurids), the dominant herbivores of the Late Cretaceous. In our research we are studying: 1) the steps by which hadrosaur teeth became more complex, 2) how the mechanics of their dentition changed with each step, 3) how such changes allowed for the processing of different food types, and finally 4) how their extensive worldwide radiations were made possible by dental changes. We are specifically documenting the shape and microstructure of the teeth throughout the group, including some of the earliest and latest representatives. From growth lines found in the samples we are determining how long each dinosaur?s teeth took to form, wear down, and be replaced. We are then using these data to create computerized engineering models of the dentitions and using them to explain how the chewing surfaces of each species were created. Ultimately we will correlate these data with dietary information and geographic radiations to gain a comprehensive understanding of how hadrosaurids came to dominant herbivorous roles during the age of dinosaurs. The results will serve as a model for understanding the genesis of complex dental structures and will be of interest to investigators in myriad scientific disciplines (e.g. vertebrate paleontology, paleobiology, evolutionary biology, anthropology, integrative biology, comparative physiology, ecology, herpetology, and mammalogy). Additional benefits of this study include educational opportunities for students and teachers. Justifications and descriptions of the research and findings will be posted on the internet for public access along with an archive of research images. Through the American Museum of Natural History (AMNH) Education Department?s summer intern program, high school students have the opportunity for hands-on participation in the project. Teacher training (for high school and middle school teachers) will also be conducted as a result of this grant. Teacher Professional Development Workshops, focusing on dinosaur evolutionary feeding ecology, will be held at the Gottesman Center at the AMNH. In addition this research will be shared with teachers who participate in hands-on histology activities during a special continuing education program at Florida State University.
