Nodosaurus (meaning "knobbed lizard") was a genus of herbivorous ankylosaurian dinosaur from the Late Cretaceous, the fossils of which are found in North America. Two incomplete specimens have been discovered in Wyoming and Kansas, and no skulls. 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 13 to 20 feet (4.0 to 6.1 m) 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.