Sunday, July 26, 2015

Styracosaurus: Beast of the Week

This week we will be checking out Styracosaurus, the spike-frilled dinosaur!  Styracosaurus albertensis lived in what is now Alberta, Canada during the Late Cretaceous Period, 75 million years ago.  From beak to tail it measured about eighteen feet long and was a plant-eater.  The genus name, Styracosaurus, translates to "Spike Lizard/Dinosaur" 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, Corythosaurus, and Euoplocephalus.

Styracosaurus engaging in a display standoff.  Reconstruction by Christopher DiPiazza.  Get out of the way, snake!  It's about to GO DOWN!

Styracosaurus is considered a ceratopsian dinosaur (frills, beaks, and horns), in the same family as Triceratops.  More specifically, however, it is considered a centrosaurine ceratopsian, which are characterized by having very deep snouts and shorter frills, relatively speaking.  Other examples centrosaurine ceratopsians are Pachyrhinosaurus and Nasutoceratops.

The most striking feature about Styracosaurus is definitely its frill and horn ornamentation.  It had one straight horn on its snout and around its frill were eight more large horns/spikes on the top (four on each side) and a series of smaller horns, called epoccipitals on the sides.  The most popular idea for the purpose of these horns is for display, but it is possible they were good deterrents against would-be predators too.  Many defensive weapons animals evolve have similar designs to what you see on Styracosaurus's skull, long, straight spears facing outwards, keeping enemies as far away as possible.  Think of animals like hedgehogs, porcupines, and certain kinds of lizards, like Bearded Dragons, or Horned Toads for modern examples of this. The skulls of Styracosaurus and other centrosaurine dinosaurs have been examined closely by scientists and little to no signs of damage from other horns could be found, leading most to believe that they probably weren't fighting each other with them...at least not on the face.

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

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.  Other plant eaters, like Euoplocephalus with its wide beak, seem to have been more generalists, likely sucking up pretty much any plant material that was in front of them.   In the back of Styracosaurus' mouth were hundreds of small teeth packed together, forming what are called dental batteries.  These structures were designed for slicing tough plant material, rather than grinding it, which is what you would see in a duckbill dinosaur's mouth, which also had dental batteries but in a flatter shape.

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 and drown in flash floods all at once.  Therefore it could be possible Styracosaurus may have still preferred the 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

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.

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.

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