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Albertaceratops

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Albertaceratops
Temporal range: Late Cretaceous, 77.5 Ma
Skull in Philip J. Currie Dinosaur Museum
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Ornithischia
Clade: Neornithischia
Clade: Ceratopsia
Family: Ceratopsidae
Subfamily: Centrosaurinae
Clade: Albertaceratopsini
Genus: Albertaceratops
Ryan, 2007
Species:
A. nesmoi
Binomial name
Albertaceratops nesmoi
Ryan, 2007

Albertaceratops (meaning "Alberta horned face") is a genus of centrosaurine horned dinosaur from the middle Campanian-age Upper Cretaceous Oldman Formation of Alberta, Canada.[1]

Description

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Restoration

Albertaceratops is unusual in combining long brow horns with an otherwise centrosaurine skull, as centrosaurines normally possess short brow horns. Over its nose was a bony ridge, and on its frill were two large outwardly-projecting hooks.[1] Its size has been estimated at 5.8 metres (19 ft) and 3,500 kilograms (7,700 lb).[2]

Discovery and naming

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Albertaceratops skull
Skull of the Albertaceratops nesmoi holotype, TMP 2001.26.1

Albertaceratops is known from a single complete skull (TMP.2001.26.1) found in August 2001 and skull and postcranial fragments. A phylogenetic analysis carried out by its describer, Michael J. Ryan, found it to be the most basal centrosaurine.[1] Additional specimens were reported from a bonebed in the Judith River Formation of Montana, which is equivalent to the Oldman Formation and differentiated only by the Canada–US border. However, further study showed these remains to come from a different centrosaurine, Medusaceratops. Both ceratopsids lived during the same time period, about 77.5 million years ago.[3]

The specific name, A. nesmoi, is derived from the name of Cecil Nesmo, a rancher living in Manyberries, Alberta, a town of less than 100 people located 71 km south of Medicine Hat. The rancher was thus honored in recognition of his efforts to aid fossil hunters.[1]

Classification

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Coronosaurus and Albertaceratops in environment
Size of Albertaceratops compared to a human

The cladogram presented below follows a phylogenetic analysis by Chiba et al. (2017), which included a systematic re-evaluation of Medusaceratops lokii:[4]

Centrosaurinae
Nasutoceratopsini

Avaceratops lammersi (ANSP 15800)

MOR 692

CMN 8804

Nasutoceratops titusi

Malta new taxon

Xenoceratops foremostensis

Sinoceratops zhuchengensis

Wendiceratops pinhornensis

Albertaceratops nesmoi

Medusaceratops lokii

Eucentrosaura
Centrosaurini

Rubeosaurus ovatus

Styracosaurus albertensis

Coronosaurus brinkmani

Centrosaurus apertus

Spinops sternbergorum

Pachyrhinosaurini

Einiosaurus procurvicornis

Pachyrostra

Achelousaurus horneri

Pachyrhinosaurus canadensis

Pachyrhinosaurus lakustai

Pachyrhinosaurus perotorum

See also

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References

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  1. ^ a b c d Ryan, Michael J. (2007). "A New Basal Centrosaurine Ceratopsid from the Oldman Formation, Southeastern Alberta". Journal of Paleontology. 81 (2): 376–396. doi:10.1666/0022-3360(2007)81[376:ANBCCF]2.0.CO;2. ISSN 0022-3360. S2CID 130607301.
  2. ^ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 259
  3. ^ Ryan, Michael J.; Russell, Anthony P., and Hartman, Scott. (2010). "A New Chasmosaurine Ceratopsid from the Judith River Formation, Montana", In: Michael J. Ryan, Brenda J. Chinnery-Allgeier, and David A. Eberth (eds), New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium, Indiana University Press, 656 pp. ISBN 0-253-35358-0.
  4. ^ Kentaro Chiba; Michael J. Ryan; Federico Fanti; Mark A. Loewen; David C. Evans (2018). "New material and systematic re-evaluation of Medusaceratops lokii (Dinosauria, Ceratopsidae) from the Judith River Formation (Campanian, Montana)". Journal of Paleontology. 92 (2): 272–288. Bibcode:2018JPal...92..272C. doi:10.1017/jpa.2017.62. S2CID 134031275.
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