Kingdom Animalia
Phylum Chordata
Superclass Tetrapoda
Class Reptilia
Subclass Diapsida
Superorder Dinosauria
Order Ornithischia
Family Thescelosauridae
Subfamily Thescelosaurinae
Genus Thescelosaurus
1st Species Thescelosaurus neglectus
2nd Species Thescelosaurus garbanii
3rd Species Thescelosaurus assiniboiensis
Other attributes
Time Range 66 mya
Location United States of America, Canada
Name Meaning Marvelous reptile
Physical Dimensions 4 meters long
Weight 77 kilograms
Dietary Classification Herbivore (presumed omnivore)

Thescelosaurus is a thescelosaurid dinosaur from the Late Cretaceous of the United States of America and Canada. It was named in 1913 by Charles W. Gilmore. It was one of the last primitive ornithischians, and was also one of the most widespread.


Thescelosaurus had a slightly more unique body plan than other ornithischians. It had a broad body, semi-short legs, a long tail, semi-short arms, a small beak in front of its mouth, and large, eagle-like brows near the top of its eyes. Its body would have been covered in scaly skin.


Thescelosaurus would have been an herbivore, feeding on plants low to the ground by shredding them with its beak, and holding them in its mouth (specifically by its cheeks) when chewing. However, its leaf-shaped teeth (designed for chewing plants) were in the back of its mouth, lying right behind a front row of pointy teeth, so many may speculate that it also either preyed on small animals like lizards, or scavenged the kills of larger predators (in addition to its herbivorous diet).


Thescelosaurus would have been a slow runner, due to its heavy build and unusual leg structure (its upper legs were longer than its lower legs). However, its lifestyle was the key to its survival. Many may speculate that it either lived by rivers and streams, or it may have lived in floodplains; however, many specimens have been dug out of sandstone, which leans more towards living near rivers, as opposed to the floodplains' mudstone. This may have provided an escape route for them, as once a predator like Tyrannosaurus showed up, the ornithischian would have jumped into the water and swam away, and it would have been unhindered by aquatic vegetation due to its semi-short legs.

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