Styracosaurus: Beast of the Week

This week we will be checking out Styracosaurus albertensis, the spike-frilled dinosaur!  Styracosaurus lived in what is now Alberta, Canada, during the late Cretaceous period, between 75.5 and 75.2 million years ago.  From beak to tail it measured about eighteen feet long and was a plant-eater when alive.  The genus name, Styracosaurus, translates to "Spike Reptile" in reference to the eight long spikes growing from the sides of its frill.  When alive, Styracosaurus would have shared its habitat with other dinosaurs like Parasaurolophus, Lambeosaurus, and Gorgosaurus.

Life reconstruction in watercolors by Christopher DiPiazza of two adult Styracosaurus working out a territory dispute. 

After Triceratops, Styracosaurus is possibly the most recognized member of the ceratopsian group of dinosaurs by image if not by name.  As far as dinosaur toys go, if any ceratopsian is going to show up in addition to Triceratops in a package, its almost always Styracosaurus.  (I'm actually genuinely surprised that out of the four ceratopsians that ultimately showed, it never appeared in a Jurassic Park/World movie). It's popularity is probably due to the fact that it has been known about for a lot longer than the majority of ceratopsians, formerly described over 100 years ago, so it's had time to make appearances in books and other popular media.  The other reason is Styracosaurus is just so striking to look at, even among currently known ceratopsian diversity.  Like its genus name suggests, adult Styracosaurus had a series of several extremely long spikes growing from the top edge of the frill.  In addition to these, it also had shorter spikes lining the lower edges of the frill, as well as a long horn growing out of the top of the snout.  We now know that Styracosaurus was capable of exhibiting a decent degree of variation among adults, with the number of long frill spikes ranging between four and eight depending on the individual.  There is even one specimen with seven frill spikes, showing that they were capable of expressing asymmetry in their head ornamentation.  

Front view of the Styracosaurus' skull on display at the American Museum of Natural History in New York.

The evolutionary purpose of Styracosaurus' head ornamentation, like those of most ceratopsians, is somewhat debated.  There's always the likelihood they were for display within the species, but there's also a strong chance they were additionally used as actual weapons, whether for fighting members of its own species for dominance, or against potential predators.  The sideways-facing frill spikes particularly seem like they would be effective at deterring the hungry jaws of tyrannosaurs away from the neck.  A Styracosaurus skeleton described in 2020, possesses proportionally much shorter frill spikes, a shorter nose horn, and an overall smaller body size than most other known Styracosaurus specimens on the fossil record, and is therefore thought to be of a juvenile individual.  Shorter horns in immature animals suggests they had some sort of sexual or social display purpose.  

Photograph of what is thought to be a juvenile Styracosaurus skull from the 2020 paper by Caleb Brown et al. Note the shorter frill horns and nose horn. 

The beak of Styracosaurus was narrow, and the lower beak tip was extremely long and curved upwards.  This would be a good adaptation for clipping specific plants to eat, much like a giant pair of rose trimmers.  Because of this it is likely that Styracosaurus and its relatives were more selective feeders rather than generalists, which are more adept at sucking up any plant material that's infront of them.   In the back of Styracosaurus' mouth were hundreds of small teeth packed together, forming what are called dental batteries.  These structures were good for finely slicing tough plant material, rather than grinding it.

Side view of the same Styracosaurus specimen as above at the American Museum of Natural History.

There have been bone beds comprised of multiple Styracosaurus skeletons discovered, but it is still unclear as to if they were actually herding animals.  The reason for this is because the area in which the dinosaurs seemed to have died was a riverbed at the time of their death.  Frequently, animals, herding or not, will congregate at water sources like this hoping to drink and then drown in flash floods all at once.  Therefore it could be possible Styracosaurus may have still preferred the more solitary lifestyle.  It would be difficult to cuddle with those big spikes anyway.

That is all for this week!  As always feel free to comment below or on our facebook page!

References

Brown, C.; Holmes, R.; Currie, P. (2020). "A subadult individual of Styracosaurus albertensis (Ornithischia: Ceratopsidae) with comments on ontogeny and intraspecific variation in Styracosaurus and Centrosaurus". Vertebrate Anatomy Morphology Palaeontology. 8 (1): 67–95.

Eberth, David A.; Getty, Michael A. (2005). "Ceratopsian bonebeds: occurrence, origins, and significance". In Currie, Phillip J., and Koppelhus, Eva. Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Bloomington: Indiana University Press. pp. 501–536.

Holmes, R.B.; Persons, W.S.; Singh Rupal, B.; Jawad Qureshi, A.; Currie, P.J. (2020). "Morphological variation and asymmetrical development in the skull of Styracosaurus albertensis". Cretaceous Research. 107: 104308.
Lambe, L.M. (1913). "A new genus and species from the Belly River Formation of Alberta". Ottawa Naturalist 27: 109–116.

Ostrom, J. H. (1966). "Functional morphology and evolution of the ceratopsian dinosaurs". Evolution 20 (3): 290–308.

Tait, J.; Brown, B. (1928). "How the Ceratopsia carried and used their head". Transactions of the Royal Society of Canada 22: 13–23.

Tanke, D. H, and Farke, A. A. (2006). Bone resorption, bone lesions, and extracranial fenestrae in ceratopsid dinosaurs: a preliminary assessment. in: Carpenter, K. (ed.). Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs Indiana University Press: Bloomington. pp. 319–347.