Diversity of raptor dinosaurs in southeastern North America revealed by the first definite record from North Carolina

During the Cretaceous period, North America was divided into two landmasses, the eastern Appalachia and western Laramidia. Recent research on several sites scattered across the eastern margin of North America has allowed for the analysis of vertebrate faunas from the once obscured terrestrial fossil record of Appalachia, revealing the landmass harbored a distinctive fauna composed of mostly relict forms. One geological unit that has produced a comparatively extensive record of terrestrial vertebrates, including non-avian dinosaurs, is the Tar Heel Formation of North Carolina. Here, I report the first definitive occurrence of a dromaeosaurid from the Tar Heel Formation in the form of a tooth from a fairly large member of that group. This tooth, like others previously discovered from the southeastern portion of North America, compares favorably with those of saurornitholestine dromaeosaurids from the western United States and Canada. The North Carolina tooth differs in morphology and size from previously reported southeastern North American dromaeosaurid teeth, but is still assignable to a saurornitholestine dromaeosaurid, evincing that the diversity of carnivorous bird-like dinosaurs in the southeastern part of North America during the Late Cretaceous may have been rather low. The tooth, which is intermediate in size between those of smaller dromaeosaurids like Saurornitholestes and gigantic forms like Dakotaraptor, helps fill the gap between larger- and smaller-bodied dromaeosaurids from the Late Cretaceous.