Large caenagnathids (Dinosauria, Oviraptorosauria) from the uppermost Cretaceous of western Canada

Abstract

Large caenagnathid unguals are described from the Dinosaur Park (upper Campanian) and Frenchman (Maastrichtian) formations of Alberta and Saskatchewan, respectively. The latter constitutes the first formal description of Caenagnathidae from the Frenchman Formation. The Saskatchewan material is also notable for its large size, comparable to 'Anzu wyliei' from the coeval Hell Creek Formation, placing them among the largest caenagnathids from North America. The slightly smaller Dinosaur Park unguals may pertain to either 'Caenagnathus collinsi' (a taxon for which manual material is only tentatively known) or to an as yet unidentified large taxon. The new material demonstrates that despite an apparent reduction in diversity in the Maastrichtian, North American caenagnathid distribution did not retract notably from its Campanian maximum.