A tiny skull from southern Montana represents a new kind of horned dinosaur that had a distinctive hooked beak and was about the size of a crow. Dubbed Aquilops americanus, the specimen dates to between 104 million and 109 milllion years ago, making it the oldest known representative of the neoceratopsian group of dinosaurs in North America.
Analysis of Aquilops indicates that it is closely related to neoceratopsians that lived in Asia at around the same time, but not to later horned dinosaurs from North America. The finding suggests that the ancestors of Aquilops migrated from Asia to North America from Asia, probably via the Bering land bridge, before 104 million years ago, and that other dispersals gave rise to later horned dinosaurs in North America. Andrew A. Farke of the Raymond M. Alf Museum of Paleontology in Claremont, Calif., and his colleagues describe the new dinosaur in a paper published December 10 in PLOS ONE.