Early History of Horned and Duck-billed Dinosaurs: Discoveries in Gansu, China

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Early History of Horned and Duck-billed Dinosaurs: Discoveries inGansu, ChinaNSF EAR 1024671 PI Peter Dodson University of PennsylvaniaCo-PI You Hailu Chinese Academy of Geological Sciences, BeijingCo-PI Li Daqing, Fossil Research and Development Center, ThirdGeology and Mineral Resources Exploration Academy, Gansu Provincial Bureau of Geo-exploration and Mineral Development, LanzhouCo-PI Xu Xing, Institute of Vertebrate Paleontology and Paleoanthropology, BeijingAbstractTwo decades ago China was the third-ranked source of dinosaurs in the world, behind the United States and Mongolia. Since 1996 electrifying discoveries of avian and non-avian dinosaurs from Liaoning, Shandong, Henan, Inner Mongolia, Gansu and Xinjiang have vaulted China to the number one position in the world for dinosaur diversity. China has developed a new cohort of young researchers open to mutually enriching joint scholarship. Gansu Province in northwestern China has proven to be a rich source of abundant and exceptionally well-preserved dinosaur fossils during a critical interval of evolutionary time, the Early Cretaceous. High quality fossils have been described from Gansu only since 1997. In 2009 alone four new genera were described. We propose to sample fossil beds in Gansu that span a wide interval of the Early Cretaceous in order to document exhaustively the critical evolutionary transition from more basal herbivorous dinosaurs to more derived ones. The highly derived hadrosaurid-ceratopsid fauna that dominated Late Cretaceous faunas of the northern hemisphere had its origin during the critical interval of the Early Cretaceous when the archaic Mesozoic pteridosperm-cycadophyte-conifer-dominated flora began to change to the modern angiosperm-dominated flora. Sediments of the late Early Cretaceous Xinminpu Group of northwestern Gansu contain rich faunas of herbivorous dinosaurs. Both the ceratopsians and the ornithopods here are more derived than those of the mid Early Cretaceous Jehol Fauna of Liaoning. The proposed project includes five clear objectives: 1) to discover more horned and duck-billed dinosaurs and to locate specimens within their geological contexts to document their taphonomy. 2) To use stable isotopes of carbon and oxygen to develop a chemostratigraphy of the region and to determine trends in paleoclimate over time. 3) To use Rare Earth Element (REE) analysis to determine the rapidity of burial of fossils as in burrows and to assess trophic structure of the dinosaur communities. 4) To describe in detail the osteology of several key taxa, and to conduct a thorough re-evaluation of the taxonomy of Psittacosauridae, basal Neoceratopsia, and basal Hadrosauria. And 5) To perform the first comprehensive, species-level phylogenetic analyses for (Psittacosauridae + basal Neoceratopsia) and (basal Styracosterna + basal Hadrosauria), incorporating all newly described taxa. The result of the proposed research will be increased knowledge of both new taxa of dinosaurs and the pattern of ascent to dominance of two clades of herbivores within a controlled taphonomic, biogeochemical and biostratigraphic framework.