Genus
Valid Extinct

Sphaerotholus

Williamson and Carr 2003

Sphaerotholus is a genus of pachycephalosaurid dinosaur from the Upper Cretaceous of the western United States and Canada. To date, five species have been described: the type species, S. goodwini, from the Den-na-zin Member of the Kirtland Formation and possibly the Fossil Forest Member of the Fruitland Formation of San Juan County, New Mexico, USA; S. buchholtzae, from the Hell Creek Formation of western Carter County, Montana, USA and the Frenchman Formation of Saskatchewan, Canada; S. edmontonensis, from the Horseshoe Canyon Formation of Alberta, Canada; S. lyonsi, from the Dinosaur Park Formation (Campanian) of Alberta, Canada; and S. triregnum from the Hell Creek Formation of Garfield County, Montana, USA.

Temporal range
Triassic
Jurassic
Cretaceous
Paleogene
Neogene
252 201 145 66 0 Ma
PBDB occurrences
6
Group
Dinosaures
Herbivore Ground dwelling, gregarious Terrestrial
Sphaerotholus
click to enlarge
AMNH 0044, Sphaerotholus buchholtzae, in dorsal view with arrows denoting dorsal lesions © Joseph E. Peterson, Collin Dischler, Nicholas R. Longrich · CC BY 2.5 · Wikimedia
PBDB ↗ Wikipedia ↗
Classification
Dinosauria Unranked clade
›
Ornithischia Unranked clade
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Neornithischia Unranked clade
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Pyrodontia Unranked clade
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Cerapoda Unranked clade
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Marginocephalia Unranked clade
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Pachycephalosauria Suborder
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Pachycephalosauridae Family
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Pachycephalosaurinae Subfamily
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Sphaerotholus Genus
Fossil sites 6 geolocated sites
Distribution
Top countries
🇨🇦 Canada
3
🇺🇸 United States
3
Geological formations
Hell Creek
2
Dinosaur Park
1
Kirtland
1
Frenchman
1
Temporal distribution
Maastrichtian (72.2–66 Ma)
3
Campanian (83.6–72.2 Ma)
3
Species (5)
Sphaerotholus buchholtzae 72 Ma
Sphaerotholus edmontonensis 84 Ma
Sphaerotholus goodwini 84 Ma
Sphaerotholus lyonsi 84 Ma
Sphaerotholus triregnum 72 Ma
Images 1
Bibliography
Original description
T. E. Williamson and T. D. Carr. 2003. A new genus of derived pachycephalosaurian from western North America. Journal of Vertebrate Paleontology 22(4):779-801 DOI ↗
Bibliography (4)
D. C. Woodruff, R. K. Schott, and D. C. Evans. 2023. Two new species of small-bodied pachycephalosaurine (Dinosauria, Marginocephalia) from the uppermost Cretaceous of North America suggest hidden diversity in well-sampled formations. Papers in Palaeontology 9(6):e1535 DOI ↗
J. C. Mallon, D. C. Evans, and T. T. Tokaryk, M. L. Currie. 2015. First pachycephalosaurid (Dinosauria: Ornithischia) from the Frenchman Formation (upper Maastrichtian) of Saskatchewan, Canada. Cretaceous Research 56:426-431 DOI ↗
T. E. Williamson and T. D. Carr. 2003. A new genus of derived pachycephalosaurian from western North America. Journal of Vertebrate Paleontology 22(4):779-801 DOI ↗
B. Brown and E. M. Schlaikjer. 1943. A study of the troödont dinosaurs with the description of a new genus and four new species. Bulletin of the American Museum of Natural History 82(5):115-150