Iguanodontian dinosaurs are a diverse group of herbivores that range from small to large ?duck-billed? hadrosaurs reaching 30 feet in length. The group persisted for nearly 100 million years and is known from every modern continent. The evolution of iguanodontians crossed many major anatomical boundaries, including those of size (small to huge), locomotion type (bipedal to quadrupedal), and feeding style (small-toothed croppers to plant-processing machines with hundreds of teeth). To make sense of these evolutionary changes this study seeks to understand the diversification pattern, or phylogeny, of their evolution. To this end, fossils of all known species of iguanodontians will be examined to study their changing anatomy through time. A matrix of all observed anatomical changes will be compiled and examined using computer algorithms to determine the most likely phylogenetic relationships among iguanodontians. The evolutionary relationships will then be used to examine their geographic distributions through time.
A hypothesis of the evolutionary relationships of iguanodontians will create a framework to study their biology, such as changes in size, locomotion, and feeding mechanics. This study will also test methods for including species known only from juvenile specimens in the phylogenetic analysis; this will have potential widespread application to other groups. Finally, patterns in iguanodontian biogeography (evolution through time and space) will inform a better understanding of the biogeographic patterns of Mesozoic vertebrates.
