Nodosaurus, which translates to "knobbed lizard," is a herbivorous dinosaur belonging to the nodosaurid ankylosaurian group. Its fossils date back to the Late Cretaceous period and are exclusively found in the Frontier Formation in Wyoming.

Nodosaurus reached a size of approximately 4 to 6 meters (13 to 20 feet) in length. This ornithischian dinosaur featured a set of bony dermal plates that covered its upper body, possibly accompanied by spikes along its sides. These dermal plates were organized in bands running along its body, with narrower bands over the ribs alternating with broader plates in between. These broader plates were adorned with regularly spaced bony nodules, which contribute to the dinosaur's scientific name.

It is estimated that Nodosaurus had a length of 6 meters (20 feet) and a weight of 3.5 tonnes (3.85 short tons). Its physique included four short legs, feet with five toes, a concise neck, and an elongated, non-clubbed tail. The dinosaur's head was narrow, featuring a pointed snout, robust jaws, and small teeth. It likely fed on soft plants since it may not have been capable of chewing tough, fibrous vegetation. Alternatively, it might have used gastroliths and its extensive digestive system to process such tougher plant materials.

Nodosaurids are believed to be the precursors of ankylosaurids, and they appear to have thrived alongside their more heavily armored relatives. One noticeable resemblance between nodosaurids and ankylosaurids is the presence of small pieces of bony armor, often referred to as osteoderms or scutes, which extended across the back and upper flanks of their bodies.

However, there are significant distinctions. Unlike ankylosaurids, nodosaurids lack a clubbed tail, possess a narrower mouth, and do not exhibit the advanced nasal adaptations that are characteristic of more evolved ankylosaurids.