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Temporal range: Late Cretaceous, 77.5 Ma
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Family: Ceratopsidae
Subfamily: Centrosaurinae
Genus: Albertaceratops
Type species
Albertaceratops nesmoi
Ryan, 2007

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



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[edit]

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 chasmosaurine, 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]



A phylogenetic analysis carried out by its describer, Michael J. Ryan, found it to be the most basal centrosaurine.[1] The following phylogenetic tree is from Ryan et al. (2016):[4]


Diabloceratops eatoni


Avaceratops lammersi (ANSP 15800)

MOR 692

CMN 8804

Nasutoceratops titusi

Malta new taxon

Xenoceratops foremostensis

Sinoceratops zhuchengensis

Wendiceratops pinhornensis


Rubeosaurus ovatus

Styracosaurus albertensis

Spinops sternbergorum

Centrosaurus apertus

Coronosaurus brinkmani


Einiosaurus procurvicornis

Achelousaurus horneri


Pachyrhinosaurus canadensis

Pachyrhinosaurus lakustai

Pachyrhinosaurus perotorum

Albertaceratops nesmoi

See also[edit]


  1. ^ a b c d e Ryan, M.J. (2007). A new basal centrosaurine ceratopsid from the Oldman Formation, southeastern Alberta. Journal of Paleontology 81(2):376-396.
  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. ^ Ryan, M.J.; Holmes, R.; Mallon, J.; Loewen, M.; Evans, D.C. (2017). "A basal ceratopsid (Centrosaurinae: Nasutoceratopsini) from the Oldman Formation (Campanian) of Alberta, Canada". Canadian Journal of Earth Sciences. 54. doi:10.1139/cjes-2016-0110. 

External links[edit]