STL Science Center

STL Science Center

04 March 2016


Last week extenuating circumstances did not really allow me to write up the weekend entries prior to my scheduled busy weekend. Instead, I decided not to write at all the past week and to save February's dinosaur calendar dinosaur (Saur: Mission 2016) for this week, even though it is the first week of March. The trouble, the only problem really, with the calendar dinosaur for February is that it has been covered both before this page was its own entity and in a revision series where I was going back over the fun little side project entries before Dinosaur of the Week became its own standalone thing; this was back when I used my personal Facebook page for these daily writings and no one knew it existed. Regardless, Stegosaurus is a popular dinosaur that we have now discussed three times. There are still many links, papers, and books that we have not discussed, not to mention new popular culture references, including the calendar and other artwork that has been created since that time. Due to the fact that we have covered Stegosaurus so many times, I think it is only appropriate that we discuss the species level taxa more in depth than previously. However, we will still discuss Stegosaurus as a genus as well.

(C) Brynn Metheney
Stegosaurus, as we all know, was a North American dinosaur with ties to the "old country" in cousins and sister groups spread across the entirety of the landmasses that at one time made up Laurasia. Notably Stegosaurus as it is popularly known is the state fossil of Colorado, but the genus is split between three recognized species (S. ungulatus Marsh 1879; S. stenops Marsh 1887, type species; and S. sulcatus Marsh 1887) that are very little known. This is because Stegosaurus as a genus is the name that everyone in the public sphere generally uses to discuss a dinosaur with vertical plates on its back and spikes on its tail. The dinosaur that people know best is the type, S. stenops, and rightly so, as it is the species with the most articulated skeletons discovered in the genus; this includes one "complete" individual. Stegosaurus stenops was also the shortest of the three species, measuring 7 m (23 ft) from nose tip to tail. Stegosaurus  ungulatus is the most widely known globally with a specimen attributed to the species from Portugal and has smaller back plates than S. stenops. Stegosaurus sulcatus is differentiated by plates but also by its appreciably large tail spikes. These spikes are larger than in either other species. All of this talk to tail spikes and back plates may seem reminiscent of entries on ankylosaurs and there is a reason for that. Stegosaurs belong to a clade known as Thyreophorans, the same group that encompasses the heavily armed and armored ankylyosaurs. Their name, Thyreophora, comes from the Greek words meaning "Shield Bearers" and in both groups the armor that they carried on their backs is quite evident.

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