NEW EVIDENCE OF DINOSAURS AND OTHER VERTEBRATES FROM THE UPPER CRETACEOUS WAHWEAP AND KAIPAROWITS FORMATIONS, GRAND STAIRCASE-ESCALANTE NATIONAL MONUMENT, SOUTHERN UTAH

Although dinosaurs and other vertebrate taxa have been recovered from within Grand Staircase-Escalante National Monument (GSENM) for decades, macrovertebrate materials have been limited, with no dinosaur taxa identified to species. Recent paleontological work conducted by a team from the University of Utah has yielded abundant new evidence of fossil vertebrates. This project, financially supported by GSENM and the Bureau of Land Management, has concentrated on two Upper Cretaceous Formations, the Wahweap and Kaiparowits.

Reconnaissance work in the early Campanian Wahweap Formation, carried out in cooperation with the Utah Geological Survey, has yielded remains of two ceratopsid dinosaurs, including partial skulls. Discovery of a hadrosaur bonebed lead to excavation of numerous disarticulated elements, and remote sensing techniques have been applied in an attempt to locate additional specimens. Other finds include a pachycephalosaur skull dome and osteoderms of a giant crocodilian. Vertebrate remains are significantly more abundant in the late Campanian (?Maastrichtian) Kaiparowits Formation. Discoveries include a new ceratopsid, represented by most of the skull, as well as representative elements from the postcranium. Theropod remains include partial skeletons of at least two taxa, one large-bodied tyrannosaur and one small-bodied maniraptoran.

Although the Late Cretaceous Western Interior of North America represents perhaps the best sampled time and region for dinosaur faunas, little is known of Utah, which occurs on the boundary of two latitudinally distributed biozones. Ultimately, descriptions of new taxa from the extensive Upper Cretaceous sediments of GSENM will enable comparisons with coeval faunas both north and south. This evidence, combined with paleoecological and paleogeographic data, will enable paleontologists to test an array of ecological and evolutionary hypotheses.