10 Hearty Facts About Thescelosaurus


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Thescelosaurus means “wonderful lizard”—and by the end of this article, you'll know why.

1. The First-Known Specimen was Stuffed into Shipping Crates and Forgotten About for Over 20 Years.

During the summer of 1891, a small skeleton belonging to this then-unidentified plant-eating dinosaur was found in Wyoming. The remains were carefully boxed up and arrived at what’s now called the Smithsonian Museum of Natural History—where they languished, unopened, until 1913! 

2. T. rex and Triceratops Were Among Its Neighbors.

Thescelosaurus often gets sidelined in books and museums. This likely has something to do with the fact that, 66 million years ago, it shared Western North America with several infinitely more popular creatures like Tyrannosaurus, Triceratops, Ankylosaurus, and Pachycephalosaurus. Tough break.

3. Thescelosaurus Had a Robust Build.

Nobu Tamura

With surprisingly thick ribs and limb bones, this cow-sized dinosaur was sturdily-constructed. Such stout, muscular body types have their advantages—Thescelosaurus might have used its heft to overpower small tyrannosaurs and other predators.

4. …And It Wasn’t Especially Fast.

ArthurWeasley/Wikimedia Commons

Since its discovery, Thescelosaurus has been compared to vaguely similar-looking dinosaurs such as Hypsilophodon of Europe. However, unlike that critter, Thescelosaurus clearly lacked an affinity for speed. First of all, its femur (thigh bone) is similar in size to its tibia (shinbone). But in hardcore runners like Hypsilophodon, the latter bone is significantly longer. Also, Thescelosaurus’ toe bones were—unhelpfully—on the short and stubby side.

Obviously, Thescelosaurus was no marathon contender. That doesn’t mean it couldn’t be evasive: When necessary, a low center of gravity enabled this animal to make sharp, maneuverable turns.

5. Thescelosaurus Possessed Strong Arms, but Wimpy Fingers.

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Given its broad shoulder blades and bulky arm bones, you’d think that Thescelosaurus was doing something strenuous with those forelimbs. So why did they come with small fingers and dinky claws? And while we’re on the subject, could Thescelosaurus walk around on all fours? Some paleontologists think it did so often, while others find a permanently-bipedal stance more likely. 

6. Thescelosaurus Probably Preferred Waterside Property.

A 2010 study proposed that, given the types of rocks their fossils are normally found in, Thescelosaurus usually lived around streams and rivers while “horned” dinosaurs (eg: Triceratops) targeted drier real estate. To each their own…

7. Its Skin May Have Had Hard Lumps of Armor.

Ryan Somma, Flickr

Isolated blobs of armor plating have been found in close proximity to a few Thescelosaurus skeletons. But some argue that these didn’t necessarily belong to the actual dinos; the corpses in question likely came to rest in bodies of water and, at some point, it’s possible that bony plates called “scutes” popped off of some nearby crocodilian cadavers and drifted over post mortem.

8. A New Species was Recently Announced.

In 2011, Thescelosaurus assinoboiensis was named. According to paleontologist Tim Tokaryk, “there are features in the cranium, the back end of the skull, and a few features in the pelvis” which separate T. assinoboiensis from the other known Thescelosaurus species (T. neglectus and T. garbanii).

9. “Willo”—A Very Famous Thescelosaurus Specimen—Contains “Cell-Like” Structures.

Taking a Tar Heel State road trip anytime soon? Be sure to swing by the North Carolina Museum of Natural Sciences. On the third floor, you’ll get to meet “Willo,” a dinosaurian celebrity. First uncovered in 1993, Willo is the most complete Thescelosaurus skeleton ever found, and looks plenty compelling to the naked eye. But things get even more interesting at the microscopic level: What’s been described as “cell-like” material has been spotted on “his” bones. Did this stuff actually belong to Willo himself? We can’t ascertain its origin just yet; it could have belonged to a plant he happened to have died around.

10. Also, Many Scientists Once Thought That Willo Had a Fossilized Heart.

Ryan Somma, Wikimedia Commons

Back in 2000, the world freaked out when a strange-looking lump inside his chest was interpreted as the preserved remains of a genuine dinosaur heart. Better still, it seemed like this so-called circulatory organ was of the powerful, four-chambered variety, much like ours.

Unfortunately, since then, this idea has been flatlined: A 2011 re-analysis concluded that Willo’s new claim to fame was really nothing more than a rocky concretion. Still, even without this heart of stone, Willo—like every Thescelosaurus—remains a “wonderful lizard” indeed. (Of course, dinosaurs weren’t actually lizards—they were much more akin to crocodilians. But that’s a topic for another day…)