Every month, 100,000 readers use the Dinosaur Database, but we receive no support from you. Developing and updating the database requires a lot of work. Therefore, as of September 1, 2025, the database will be closed. If you want it to remain open and be updated, please support us via the "Buy us a coffee" button available on every page.
Dinosaur: Sphaerotholus buchholtzae

Length*: | 1.8 m | 5.9 ft |
Weight*: | 30 kg | 66 lb |
*The largest known specimen
Period
Epoch: Late Cretaceous
Stage: Late Maastrichtian
Years: 72.1–66 Ma
Details
Status: valid
Author: Williamson & Carr
Year: 2002
Distribution
Area: North America
Country: USA, Canada
Region: Montana, North Dakota, South Dakota, Saskatchewan
Formation: Hell Creek, Frenchman
Locations
Sources
Material: Partial skull. Referred more than 20 individuals.
References: Williamson, T. E., & Carr, T. D. (2002). A new genus of derived pachycephalosaurian from western North America.
Mallon, J. C., Evans, D. C., Tokaryk, T. T., & Currie, M. L. (2015). First pachycephalosaurid (Dinosauria: Ornithischia) from the Frenchman Formation (upper Maastrichtian) of Saskatchewan, Canada.
D. Cary Woodruff, Mark B. Goodwin, Tyler R. Lyson & David C. Evans (2021). Ontogeny and variation of the pachycephalosaurine dinosaur Sphaerotholus buchholtzae, and its systematics within the genus.