Niobrarasaurus was a stout dinosaur that walked on all fours and was protected by an armor made of hard plates. It is part of a family of armored, plant-eating dinosaurs known as nodosaurs. The only known Niobrarasaurus fossils so far were discovered in the Niobrara chalk beds of western Kansas, which is where the dinosaur got its name. When the first one was discovered in 1930 in Gove County, Kansas, it was named Hierosaurus coleii, but the name was later changed to Niobrarasaurus coleii. Because Niobrarasaurus lived on the land but was found in rocks deposited in a Cretaceous sea, the specimens found in Kansas likely died near the shore, got swept out to sea, and sank.

The “coleii” part of the name Niobrarasaurus coleii was bestowed in honor of Virgil Cole, the geologist who collected the fossil remains in 1930. Cole described the thousands of bone fragments he found as “all the way from the size of a thimble to the size of a quart of whiskey.” No complete skeletons of Niobrarasaurus have been found.


Niobrarasaurus bones illustration
Niobrarasaurus bones collected in Kansas in 1930: 1–3 humerus (upper forearm); 4–5 chevron (bone from underside of tail); 6–9 vertebrae; 10–11 radius and ulna (lower forearm; and 12 tooth. All are shown at 1/5 to ½ actual size except the tooth, which is twice actual size (from Hierosaurus Coleii by M.G. Mehl, Denison University Bulletin, Journal of the Scientific Laboratories, v. 21, 1936).