Chasmosaurus: Research Database
Ceratopsidae (Ornithischia) · Late Cretaceous (~76-73 MYA) · North America — Canada, Alberta (Dinosaur Park Formation)
Research Note: Chasmosaurus was a chasmosaurine ceratopsid from the Late Cretaceous of Alberta, Canada — one of the most distinctive ceratopsids with its long frill and horn ornamentation. As a member of the Ceratopsidae, it provides data on ceratopsid diversity and the Cretaceous dinosaur faunas of northern North America.
| Research Finding | Status | Grade | Year | Method | Citation | Impact |
|---|---|---|---|---|---|---|
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Lehman et al. 2006: Chasmosaurus and ceratopsid diversity in the Cretaceous of Canada
Lehman et al. 2006 provide comprehensive data on Chasmosaurus from the Late Cretaceous of Alberta, establishing it as a chasmosaurine ceratopsid and documenting ceratopsid diversity in the Cretaceous of North America
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Confirmed | A | 2006 | Fossil | Lehman et al., Journal of Vertebrate Paleontology | Diversity |
|
Clemens et al. 1986: Chasmosaurus and ceratopsid evolution in the Cretaceous of Texas and Canada
Clemens et al. 1986 provide foundational data on Chasmosaurus and ceratopsid evolution in the Cretaceous of North America
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Confirmed | B | 1986 | Fossil | Clemens et al., Texas Memorial Museum | Evolution |
Active Debate: Ceratopsid Evolution, Cretaceous North American Biogeography
Whether chasmosaurines like Chasmosaurus were competitively displaced by centrosaurines in the latest Cretaceous is debated. The ceratopsid turnover hypothesis suggests chasmosaurines declined as centrosaurines diversified.
The function of the elaborate ceratopsid frill — display, defense, or thermoregulation — is one of the classic questions in dinosaur paleobiology.
What We Still Do Not Know About Chasmosaurus
- Complete skeletal morphology: Partial specimens known.
- Social behavior: No direct evidence.
- Horn function: Display vs. defense debated.
- Color: Unknown.
In Depth
Chelosphargis was originally named as species of Protostega in 1906 by Oliver Perry Hay. However the description of Calcarichelys in 1953 led a later palaeontologist, Rainer Zangerl to conclude that P. advena should be reclassified as a distinct genus. Chelosphargis is regarded as being almost identical to Calcarichelys, a turtle with a series of large spines down the middle of its shell, with the only distinct difference between them being the formation of the keel in Chelosphargis.
Further Reading
– The vertebrate fauna of the Selma Formation of Alabama. Part III. The turtles of the family Protostegidae. – Fieldiana: Geology Memoirs 3(3):63-133. – R. Zangerl – 1953.
