DINOSAUR DIVERSITY AND BIOGEOGRAPHICAL IMPLICATIONS OF THE KAIPAROWITS FORMATION (LATE CAMPANIAN), GRAND STAIRCASE-ESCALANTE NATIONAL MONUMENT, SOUTHERN UTAH

Historically, the relatively undocumented Kaiparowits Formation in southern Utah was an impediment to our understanding of dinosaur diversity across the Western Interior Basin during the Late Cretaceous. Five years ago the University of Utah and the Utah Museum of Natural history forged a collaborative effort to document the vertebrate fauna in the Kaiparowits Formation through intensive survey and excavation of its exposure within Grand Staircase-Escalante National Monument. In addition to augmenting previous knowledge of non-dinosaurian vertebrates within the monument, the Kaiparowits Basin Project has recovered at least four novel dinosaur taxa including, a new genus of chasmosaurine ceratopsian, a new species of hadrosaurine hadrosaur, a new taxon of tyrannosaur, and a new genus of oviraptorosaur, as well as previously unrecorded elements of hypsilophodont, pachycephalosaur, the lambeosaurine hadrosaur Parasaurolophus, and ornithomimid, dromaeosaur, and troodontid theropods. This dramatic increase in our understanding of the Late Campanian dinosaur fauna of Utah has provided an extensive basis for large-scale analyses of biogeographical and evolutionary patterns among coeval formations of the Western Interior Basin. Specifically, these studies reveal that the Kaiparowits ecosystem represents a complex mosiac of endemicity and regional provincialism that is variable across different dinosaur clades. These results are interpreted as stemming from inherent biological properties of individual dinosaur groups superimposed upon the climatic and geomorphological conditions of the Western Interior Basin during the Late Cretaceous of North America.