Styracosaurus albertensis: The Cretaceous Rhinoceros

Article by: J. D. Dixon
Edited by: Harry T. Jones, Lewis Haller, and Adam Manning

Styracosaurus albertensis life reconstruction by Max Bellomio. Available at: https://www.artstation.com/artwork/Yalrld.

Name: Styracosaurus albertensis
Name Meaning: Spiked Lizard
Age: Late Cretaceous (Campanian)
Diet: Herbivore
Size: 5.2 m in length approx.
Weight: 2.7 tonnes approx.
Location: Alberta (Canada)

Styracosaurus albertensis is a ceratopsian dinosaur, much like the more famous Triceratops. It was first described in 1913 by Lawrence Lambe, after C. M. Sternberg found an almost whole skull in the Dinosaur Provincial Park, Alberta, Canada. Styracosaurus albertensis is known from one bonebed in the park, which is otherwise dominated by hadrosaur (duck-billed dinosaur) remains. A second species, Styracosaurus parksi, was described in 1937 by Barnum Brown and Erich Schlaikjer, but later research by Dodson and Currie (1990) synonymised these two Styracosaurus species. Styracosaurus albertensis is found in the upper 20 metres of the Dinosaur Park Formation, which suggests that they may have actually displaced Centrosaurus, another ceratopsian, from this area.

While it belongs to the same family as Triceratops, Styracosaurus would have looked very different. Firstly, Styracosaurus only had one large horn above the nostrils, compared to the three that Triceratops’ skullwas equipped with. All ceratopsians possess a distinctive large bony neck frill. This is hypothesised as having been used for defence or display. An adult Styracosaurus had at least three pairs of parietal spikes protruding from its frill, but these frills are thought to have exhibited unique variability and asymmetry between individuals of the species. This has made analyses of dinosaur forms even more difficult than previously imagined, as many distinctions based on the shape of these frills have been made when naming North American ceratopsians. Another species of Styracosaurus, called Styracosaurus ovatus, was defined by Charles Gilmore in 1930. However, work in 2010 renamed this species as Rubeosaurus ovatus, meaning that it was even in an entirely different genus. Even so, the latest research has concluded that Rubeosaurus may be a newer synonym of Styracosaurus after all, and so these are actually the same animal. Who would have thought that all this confusion could have resulted from some ~ 70 million year old skulls?

Styracosaurus albertensis skeletal reconstruction by Scott Hartman. Available at: https://www.skeletaldrawing.com/ornithiscians/styracosaurus

Like other ceratopsians, Styracosaurus had a unique dental structure. Their mouths were equipped with a large beak and tooth batteries in the cheeks. The beak would have been appropriate for plucking, while the tooth batteries were restricted to vertical shearing, yet extreme bite forces may have been generated along these teeth. The frill may have served as the origin of some jaw muscles, allowing such a strong biteforce. As the ceratopsian head is held near to the ground, it is suggested that herbaceous vegetation, or low quality/high fibre food would have been the preferred diet of these animals. While the narrow muzzle of ceratopsians means they were all most likely selective feeders, Styracosaurus has been interpreted as more of a generalist among them, feeding on a broader range of plants than other ceratopsians.

The two tyrannosaur species Gorgosaurus libratus and Daspletosaurus torossus have also been found in the Dinosaur Park Formation, and would have posed a potential threat to Styracosaurus. However, a study of 1000 bones from the Dinosaur Park Formation showed that only around 5% of ceratopsian bones exhibited bite marks, as opposed to 14% of hadrosaurid bones, meaning Styracosaurus was probably not the top choice of delicacy for predators in the area, no doubt because of its impressive facial structures.

Styracosaurus is an amazing animal with a story riddled with confusion and discovery. It may have been a gentle grazer, but it was probably still a formidable force to be reckoned with. Whether its horn and frill were for display or defence, local predators undoubtedly wouldn’t have wanted to come into a head-on confrontation with this prehistoric beast.

Image References
[1] Styracosaurus albertensis life reconstruction by Max Bellomio. Available at: https://www.artstation.com/artwork/Yalrld.
[2] Styracosaurus albertensis skeletal reconstruction by Scott Hartman. Available at: https://www.skeletaldrawing.com/ornithiscians/styracosaurus

Information References and Further Sources
[1] Benton, M. J. (2014). Vertebrate Palaeontology. 4th ed. Oxford: Wiley-Blackwell. pp. 230-232.
[2] Brown, B., and Schlaikjer, E. M. (1937). ‘The Skeleton of Styracosaurus with the Description of a New Species’, American Museum Novitates, 955. Accessed 12th January 2020. Click Here.
[3] Dodson, P., Forster, C. A., and Sampson, S. D. (2004). ‘Ceratopsidae’, in Weishampel, D. B., Dodson, P., and Osmólska, H (2nd ed.) The Dinosauria. University of California Press. pp. 494-513.
[4] Dowswell, P., Malam, J., Mason, P., and Parker, S. (2005). The Ultimate Book of Dinosaurs. Bath: Parragon Books. pp. 154-155.
[5] Henderson, D. M. (2010). ‘Skull Shapes as Indicators of Niche Partitioning by Sympatric Chasmosaurine and Centrosaurine Dinosaurs’, in Ryan, M. J., Chinnery-Allgeier, B. J., and Eberth, D. A. New Perspectives on Horned Dinosaurs: The Royal Tyrell Museum Ceratopsian Symposium. Indiana University Press. pp. 293-307. Accessed 12th January 2020. Click Here.
[6] Holmes, R. B., Persons, W. S., Rupal, B. S., Qureshi, A. J., and Currie, P. J. (2020). ‘Morphological variation and asymmetrical development in the skull of Styracosaurus albertensis’, Cretaceous Research, 107, pp. 104308. DOI: https://doi.org/10.1016/j.cretres.2019.104308. Accessed 12th January 2020. Click Here.
[7] Holtz Jr, T. R. (2004). ‘Tyrannosauroidea’, in Weishampel, D. B., Dodson, P., and Osmólska, H (2nd ed.) The Dinosauria. University of California Press. pp. 111-136.
[8] Jacobsen, A. R. (1998). ‘Feeding behaviour of carnivorous dinosaurs as determined by tooth marks on dinosaur bones’, Historical Biology, 13 (1), pp. 17-21. DOI: https://doi.org/10.1080/08912969809386569. Accessed 12th January 2020. Click Here.
[9] McDonald, A. T., and Horner, J. R. (2010). ‘New Material of “Styracosaurusovatus from the Two Medicine Formation of Montana’, in Ryan, M. J., Chinnery-Allgeier, B. J., and Eberth, D. A. New Perspectives on Horned Dinosaurs: The Royal Tyrell Museum Ceratopsian Symposium. Indiana University Press. pp. 156-168. Accessed 12th January 2020. Click Here.
[10] Ryan, M. J., and Evans, D. C. (2005). ‘17. Ornithischian Dinosaurs’, in Curie, P. J., and Koppelhus, E. B. Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Indiana University Press. pp. 327-329. Accessed 12th January 2020. Click Here.