An ornithurine bird from the Late Cretaceous of Alberta, Canada

Abstract

The partial carpometacarpus of a basal ornithurine bird from the late Campanian of Dinosaur Provincial Park is described. Complete proximal fusion of the wrist and the presence of a pisiform process place this taxon in Ornithothoraces. Ornithurine synapomorphies include the large ventral ridge of the carpus and the concave proximal margin of the alular metacarpal, but the primitive structure of the pisiform process and extensor process preclude placement in Neornithes. The relatively thick walls of the bone and the distal placement of the extensor process are consistent with diving habits.