Genus
Valid Extinct

Stegoceras

Lambe 1902
Etymology Toit de corne

Stegoceras is a genus of pachycephalosaurid (dome-headed) dinosaur that lived in what is now North America during the Late Cretaceous period, about 77.5 to 74 million years ago (mya). The first specimens from Alberta, Canada, were described in 1902, and the type species Stegoceras validum was based on these remains. The generic name means "horn roof", and the specific name means "strong". Several other species have been placed in the genus over the years, but these have since been moved to other genera or deemed junior synonyms. Currently only S. validum and S. novomexicanum, named in 2011 from fossils found in New Mexico, remain. The validity of the latter species has also been debated, and it may not even belong to the genus Stegoceras.

Temporal range
Triassic
Jurassic
Cretaceous
Paleogene
Neogene
252 201 145 66 0 Ma
PBDB occurrences
46
Group
Dinosaures
Herbivore Ground dwelling, gregarious Terrestrial
Stegoceras
click to enlarge
Royal Tyrrell Museum Stegoceras © Cherrysweetdeal · CC BY 2.0 · Wikimedia
PBDB ↗ Wikipedia ↗
Classification
Dinosauria Unranked clade
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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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Eupachycephalosauria Unranked clade
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Stegoceras Genus
Fossil sites 46 geolocated sites
Distribution
Top countries
🇨🇦 Canada
23
🇺🇸 United States
23
Geological formations
Judith River
15
Dinosaur Park
7
Fruitland
4
Oldman
2
Kirtland
2
Hell Creek
2
Aguja
1
Temporal distribution
Maastrichtian (72.2–66 Ma)
2
Campanian (83.6–72.2 Ma)
44
Species (5)
Gravitholus albertae subjective synonym of Stegoceras validum 84 Ma
Stegoceras browni subjective synonym of Stegoceras validum 84 Ma
Stegoceras novomexicanum 84 Ma
Stegoceras validum 84 Ma
Troodon sternbergi subjective synonym of Stegoceras validum 84 Ma
Synonyms (3)
Gravitholus subjective synonym of Stegoceras
Hanssuessia subjective synonym of Stegoceras
Ornatotholus subjective synonym of Stegoceras
Images 6
Bibliography
Original description
L. M. Lambe. 1902. New genera and species from the Belly River Series (mid-Cretaceous). Geological Survey of Canada Contributions to Canadian Palaeontology 3(2):25-81
Bibliography (15)
S. L. Wick and T. M. Lehman. 2024. A rare ‘flat-headed’ pachycephalosaur (Dinosauria: Pachycephalosauridae) from West Texas, USA, with morphometric and heterochronic considerations. Geobios 86(78):89–106 DOI ↗
S. E. Jasinski and R. M. Sullivan. 2011. Re-evaluation of pachycephalosaurids from the Fruitland-Kirtland transition (Kirtlandian, late Campanian), San Juan Basin, New Mexico, with a description of a new species of Stegoceras and a reassessment of Texacephale langstoni. Fossil Record 3. New Mexico Museum of Natural History and Science Bulletin 53:202-215
R. M. Sullivan and S. G. Lucas. 2006. The pachycephalosaurid dinosaur Stegoceras validum from the Upper Cretaceous Fruitland Formation, San Juan Basin, New Mexico. Late Cretaceous Vertebrates from the Western Interior. New Mexico Museum of Natural History and Science Bulletin 35:329-330
R. M. Sullivan. 2003. Revision of the dinosaur Stegoceras Lambe (Ornithischia, Pachycephalosauridae). Journal of Vertebrate Paleontology 23(1):181-207 DOI ↗
J. E. Storer. 1993. Additions to the mammalian paleofauna of Saskatchewan. Modern Geology 18(4):475-487
M. B. Goodwin. 1990. Morphometric landmarks of pachycephalosaurid cranial material from the Judith River Formation of northcentral Montana. Dinosaur Systematics: Perspectives and Approaches, Cambridge University Press, Cambridge DOI ↗
A. R. Fiorillo. 1989. The vertebrate fauna from the Judith River Formation (Late Cretaceous) of Wheatland and Golden Valley counties, Montana. Mosasaur 4:127-142
M. B. Goodwin. 1989. New occurrences of pachycephalosaurid dinosaurs from the Hell Creek Formation, Garfield County, Montana. Journal of Vertebrate Paleontology 9(3, suppl.):23A
P. M. Galton and H.-D. Sues. 1983. New data on pachycephalosaurid dinosaurs (Reptilia: Ornithischia) from North America. Canadian Journal of Earth Sciences 20(3):462-472 DOI ↗
W. P. Wall and P. M. Galton. 1979. Notes on pachycephalosaurid dinosaurs (Reptilia: Ornithischia) from North America, with comments on their status as ornithopods. Canadian Journal of Earth Sciences 16:1176-1186 DOI ↗
A. Sahni. 1972. The vertebrate fauna of the Judith River Formation, Montana. Bulletin of the American Museum of Natural History 147(6):321-412
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
C. W. Gilmore. 1924. On Troodon validus, an orthopodous dinosaur from the Belly River Cretaceous of Alberta, Canada. Department of Geology, University of Alberta Bulletin 1:1-43
L. M. Lambe. 1918. The Cretaceous genus Stegoceras typifying a new family referred provisionally to the Stegosauria. Proceedings and Transactions of the Royal Society of Canada, series 3 12:23-36
L. M. Lambe. 1902. New genera and species from the Belly River Series (mid-Cretaceous). Geological Survey of Canada Contributions to Canadian Palaeontology 3(2):25-81