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Vagaceratops; Temporal range: Late Cretaceous, 76.2 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Cast of the holotype skull, Canadian Museum of Nature
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	†Ornithischia
Clade:	†Neornithischia
Clade:	†Ceratopsia
Family:	†Ceratopsidae
Subfamily:	†Chasmosaurinae
Genus:	†Vagaceratops; Sampson et al., 2010
Species:	†V. irvinensis
Binomial name
	†Vagaceratops irvinensis; (Holmes et al., 2001 [originally Chasmosaurus])
Synonyms
	Chasmosaurus irvinensis Holmes et al., 2001;

Vagaceratops (meaning "wandering (vagus, Latin) horned face", in reference to its close relationship with Kosmoceratops from Utah) is a genus of herbivorous ceratopsian dinosaur. It is a chasmosaurine ceratopsian which lived during the Late Cretaceous period (late Campanian) in what is now Alberta. Its fossils have been recovered from the Upper Dinosaur Park Formation. It is sometimes included in the genus Chasmosaurus as Chasmosaurus irvinensis instead of being recognized as its own genus.

History

In 2010, paleontologist Scott D. Sampson and colleagues named Vagaceratops (from the Dinosaur Park Formation, whose sole species, C. irvinensis, was formerly placed in Chasmosaurus), as well as Kosmoceratops and Utahceratops (from the Kaiparowits Formation) in the same article.^[1] These genera, which were considered unusual compared to typical members of their group, were part of a spate of ceratopsian discoveries in the early 21st century, when many new taxa were named (a 2013 study stated that half of all valid genera were named since 2003, and the decade has been called a "ceratopsid renaissance").^[2]^[3]^[4]

Description

Vagaceratops was a medium-sized ceratopsian, reaching 4.5 m (15 ft) in length and weighing 1.2 t (1.3 short tons).^[5] It is known primarily from three fossil skulls. Although the general structure was typical of ceratopsids (i.e. a parrot-like beak, large neck frill, and nasal horn) it has some peculiarities. The skulls are characterized by a reduced supraorbital horn, brow horns that are reduced to low bosses and a larger snout compared to related animals. Vagaceratops had smaller parietal fenestrae than most ceratopsids and had a strange configuration of epoccipitals (bones surrounding the frill). It possessed ten epoccipitals, eight of which were centrally flattened, curved forward and upward and fused together to form a jagged margin along the back of the frill. The frill was shorter and more square-shaped than other chasmosaurines, being wider than it was long.

Classification

Vagaceratops was named by Scott D. Sampson, Mark A. Loewen, Andrew A. Farke, Eric M. Roberts, Catherine A. Forster, Joshua A. Smith, and Alan L. Titus in 2010, and the type species is Vagaceratops irvinensis.^[1] This species was originally described as a species of Chasmosaurus (C. irvinensis) in 2001.^[6] Its relationships remain debated. Vagaceratops has variously been allied with Kosmoceratops^[1] or with Chasmosaurus.^[7]^[6]

The cladogram below is the phylogeny of the Chasmosaurinae by Brown et al. (2015):^[8]

Ceratopsidae

Centrosaurinae

Chasmosaurinae

	Vagaceratops irvinensis

	Kosmoceratops richardsoni

	Chasmosaurus belli

	Chasmosaurus russeli

Mojoceratops perifania

Agujaceratops mariscalensis

	Utahceratops gettyi

	Pentaceratops sternbergii

	Bravoceratops polyphemus

	Coahuilaceratops magnacuerna

	Anchiceratops ornatus

	Arrhinoceratops brachyops

Triceratopsini

Regaliceratops peterhewsi

Eotriceratops xerinsularis

Ojoceratops fowleri

Titanoceratops ouranos

Nedoceratops hatcheri

	Torosaurus latus

	Torosaurus utahensis

	Triceratops horridus

	Triceratops prorsus

Recently it has been suggested that Chasmosaurinae had a deep evolutionary split between a Chasmosaurus clade and a Pentaceratops clade. Vagaceratops was hypothesized to be the last member of the Chasmosaurus clade from northern Laramidia, with the last representative of the clade being its close relative Kosmoceratops.^[9]

References

^ ^a ^b ^c Scott D. Sampson; Mark A. Loewen; Andrew A. Farke; Eric M. Roberts; Catherine A. Forster; Joshua A. Smith & Alan L. Titus (2010). "New Horned Dinosaurs from Utah Provide Evidence for Intracontinental Dinosaur Endemism". PLOS ONE. 5 (9): e12292. Bibcode:2010PLoSO...512292S. doi:10.1371/journal.pone.0012292. PMC 2929175. PMID 20877459.
^ Carpenter, Patti (8 October 2013). "Big-Nosed, Long-Horned Dinosaur Discovered in Utah". Natural History Museum of Utah. Archived from the original on 2013-10-08. Retrieved 9 January 2024.
^ Loewen, M.; Farke, A. A.; Sampson, S. D.; Getty, M. A.; Lund, E. K.; O’Connor, P. M. (2013). "Ceratopsid dinosaurs from the Grand Staircase of Southern Utah". In Titus, A.; Loewen, M. (eds.). At the Top of the Grand Staircase: The Late Cretaceous of Southern Utah. Bloomington: Indiana University Press. pp. 488–503. ISBN 978-0-253-00883-1.
^ Dodson, P. (2013). "Ceratopsia increase: history and trends". Canadian Journal of Earth Sciences. 50 (3): 294–305. Bibcode:2013CaJES..50..294D. doi:10.1139/cjes-2012-0085.
^ Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2 ed.). Princeton: Princeton University Press. p. 296. ISBN 978-0-691-16766-4.
^ ^a ^b R. B. Holmes; C. A. Forster; M. J. Ryan & K. M. Shepherd (2001). "A new species of Chasmosaurus (Dinosauria: Ceratopsia) from the Dinosaur Park Formation of southern Alberta". Canadian Journal of Earth Sciences. 38 (10): 1423–1438. Bibcode:2001CaJES..38.1423H. doi:10.1139/cjes-38-10-1423.
^ Longrich, N.R., 2011. Titanoceratops ouranos, a giant horned dinosaur from the Late Campanian of New Mexico. Cretaceous Research 32, 264-276.
^ Brown, Caleb M.; Henderson, Donald M. (June 4, 2015). "A new horned dinosaur reveals convergent evolution in cranial ornamentation in ceratopsidae". Current Biology. 25 (12): 1641–8. Bibcode:2015CBio...25.1641B. doi:10.1016/j.cub.2015.04.041. PMID 26051892.
^ Fowler, Denver W.; Fowler, Elizabeth A. Freedman (2020-06-05). "Transitional evolutionary forms in chasmosaurine ceratopsid dinosaurs: evidence from the Campanian of New Mexico". PeerJ. 8: e9251. doi:10.7717/peerj.9251. ISSN 2167-8359. PMC 7278894. PMID 32547873.