Stegosaurus

Name & Basics
Genus: Stegosaurus

Name Means: Roof Lizard

Lived During: Jurassic Period



This dinosaur will come up in the middle third of the World of Dinosaurs Fall 2020 course. See the syllabus for more.

Anatomy

 * The bony plates on the animal's back are not actually attached to the internal skeleton directly. Instead, these are scutes, the skin bones similar to what you find on an alligator.
 * Behold, Scott Hartman's skeletal reconstruction: https://www.skeletaldrawing.com/ornithiscians/stegosaurusStegosaurus.jpg
 * And here are some photos of a fossil skeleton reconstruction on exhibit at the Los Angeles County Natural History Museum.

Phylogeny
Here's a hierarchical view. Click the links for more info, including cladograms.

Dinosauria


 * Ornithischia
 * Genosauria
 * Thyreophora
 * Stegosauria

We will casually refer to the group of armored dinosaurs that have large plates sticking off of their backs as Stegosaurids. The "ids" ending shows we're not being very picky about the taxonomic rank of this group (because we don't focus much on that in this class).


 * Other fun stegosaurids include:
 * Kentosaurus
 * Other armored dinosaurs (Thyreophora) to enjoy include the
 * Ankylosaurs

Biomechanics

 * What were the plates for?
 * Why are the back legs so long?

Fossil Record
Stegosaurids lived during the Jurassic Period.

Their fossils are typically found as individuals, rather than large groups.

Juvenile stegosaurids are now found that include plates on their backs.

Their teeth have features well-suited to trimming plant matter, but they do not have sophisticated grinding teeth.

Ecology
Stegosaurids ate plants. From their teeth and body shape, we interpret that an individual stegosaur may have needed to bite off a huge volume of plant chunks, then slowly digest these in their gut to get some nutrients out. Sophisticated chewing, as in the duck-billed Hadrosaur dinosaurs (i.e., Parasarolophus), allows an animal to separate of the plant's juicy bits from the less-useful structural bits (think about putting celery in a juicer or blender), but stegosaurs did NOT have teeth like that. (sigh!)

Stegosaurids probably lived independently rather than in a herd - more like panda bears than deer! We interpret this based off their fossil locations. Even in Dinosaur National Monument, where a fairly-well articulated stegosaur skeleton is found buried among many other contemporaneous dinosaurs, there are few stegosaurs compared to everything else.

Biogeography
View where stegosaurid fossils have been found on a map of the world (with today's countries), using the Paleobiology Database:

And where we interpret those fossils were on Pangea during the Jurassic Period:

Links to images, 3D models, etc.