NEW CAENAGNATHID (THEROPODA: OVIRAPTOROSAURIA) MATERIAL FROM THE LANCE FORMATION (MAASTRICHTIAN) OF WYOMING

The Maastrichtian (uppermost Cretaceous) deposits of North America are well-known for their numerous dinosaur fossils, including such well known genera as Tyrannosaurus and Triceratops. In 2014, a new genus of large caenagnathid oviraptorosaur, named Anzu wyliei was announced from the Hell Creek Formation of North and South Dakota. Additional finds have turned up in the Hell Creek Formation in both South Dakota and Montana. Nevertheless, Anzu continues to be a rare taxon with only a handful of specimens described. A recently discovered bonebed in the Lance Formation of eastern Wyoming has yielded associated skeletons of multiple dinosaur taxa including Edmontosaurus, Triceratops, Thescelosaurus, and Anzu. The Anzu fossils come from the left leg of a single individual, spread out along a single trajectory. The discovered material includes a tibia, fibula, astragalocalcaneum, metatarsal I, possible metatarsal II, possible metatarsal IV, two pedal phalanges, and a pedal ungual. We refer this specimen to Anzu due to the presence of the tubercle on the astragalocalcaneum as well as the similarity of the tibia and fibula to the Anzu type series. A radius was also discovered nearby at the site that may pertain to the same species and individual. These discoveries increase the known specimens of Anzu and are the first specimens described from the Lance Formation.