Nodosaurus (meaning "knobbed lizard") was a genus of herbivorous ankylosaurian dinosaur from the Late Cretaceous, the fossils of which are found in North America. One incomplete specimen has been discovered in the Frontier Formation of Wyoming. One of the first armored dinosaurs to be discovered in North America,
Nodosaurus was named by Othniel Charles Marsh in 1889.
This nodosaurid ankylosaur was about 3.9 to 6 metres (13 to 20 ft) long. It was an ornithischian dinosaur with bony dermal plates covering the top of its body, and it may have had spikes along its side as well. The dermal plates were arranged in bands along its body, with narrow bands over the ribs alternating with wider plates in between. These wider plates were covered in regularly arranged bony nodules, which give the animal its scientific name.
Armour of Nodosaurus.
It had four short legs, five-toed feet, a short neck, and a long, stiff, clubless tail. The head was narrow, with a pointed snout, powerful jaws, and small teeth. It perhaps ate soft plants, as it would have been unable to chew tough, fibrous ones; or alternatively it may have processed the latter with gastroliths and its enormous intestinal apparatus.
It is thought that without a club on its tail, Nodosaurus would have been left without much in terms of active defenses. When threatened, it probably dropped to the ground so that only its armored back and sides were exposed, much like modern-day hedgehogs.
Various nodosaur scutes found in the Eastern US have a good chance of being identified as, and probably are, scutes of the genus Nodosaurus. One of them was attributed to Hierosaurus sternbergi, now considered a synonym of Nodosaurus.