Monday, 19 November 2012

B is for "Brachyceratops"

To continue with our 'A-Z of Dinosaurs from Alberta', we have B is for "Brachyceratops" this week. You will notice that "Brachyceratops" is surrounded by quotation marks. This indicates that the name is not valid, which will be explained here. 

"Brachyceratops" was named in 1914 from some partial skeletons found in Montana [1]. The name means 'short-horned face', because it has an abbreviated face compared to other ceratopsians. It comes from the Upper Cretaceous, approximately 75 million years ago. It is characterised by its short face, small horns over its eyes (supraorbital horns), and small size. It has also been found in Alberta [2].
"Brachyceratops". Image from Wikimedia Commons (Nobu Tamura)
Unfortunately, the characteristics that were used to differentiate it from other species are also characteristic of juvenile ceratopsians, specifically centrosaurine ceratopsians [3]. It is found in areas where other ceratopsians like Einiosaurus and Achelusaurus are found, and may represent juveniles of these genera, while one specimen has been identified as a juvenile Rubeosaurus [3,4,5]. Because of this, "Brachyceratops" has been classified as a nomen dubium, or 'dubious name', and is not generally considered to be a valid genus of dinosaur, as all specimens are juveniles of other ceratopsian dinosaurs. It can be difficult to determine which dinosaur the juvenile belongs to, but it seems that "Brachyceratops" may represent different ceratopsian juveniles. 
Rubeosaurus from McDonald [5].
Other B dinosaurs from Alberta
There are no other non-avian dinosaurs starting with B from Alberta, but there is one bird called Baptornis.

Stay tuned for next week: C is for Chasmosaurus!

1. Gilmore, CW. 1914. A new ceratopsian dinosaur from the Upper Cretaceous of Montana, with not on Hypacrosaurus. Smithsonian Miscellaneous Collections 63(3): 1-10.
2. Russell, LW. 1934. Fauna of the upper Milk River Beds, southern Alberta. Transactions of the Royal Society of Canada, series 3 4(29): 115-128.
3. Sampson, SD, Ryan, MJ, and Tanke, DH. 1997. Craniofacial ontogeny in centrosaurine dinosaurs (Ornithischia: Ceratopsidae): taxonomic and behavioral implications. 
4. Ryan, MJ, Holmes, R, and Russell, AP. 2007. A revision of the late Campanian centrosaurine ceratopsid genus Styracosaurus from the Western Interior of North America. Journal of Vertebrate Paleontology 27: 944-962. 

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