Where were their fossils found?
Pachycephalosaurus was discovered in 1938 by William Winkley on the family ranch outside of Ekalaka, Montana, USA. It was named Pachycephalosaurus in 1943 by Barnum Brown and Erich M. Schlaikjer. Although complete fossils are rare, many thick skull fragments have been found. Pachycephalosaurus and other pachycephalosaur fossils have been found in Alberta, Canada, the western United States, the Isle of Wight, Mongolia and Madagascar.
