Nodosaurids are a group of 6-25ft long ankylosaurs of the Mid Jurassic to Late Cretaceous periods. The name means 'knobbly lizards' and derives from the nodules in the skin which helped to armor these dinosaurs. Nodosaurids were herbivores that walked on all fours. They had short limbs, a short neck, a fairly narrow head with a pointed snout and large jaws with small leaf-shaped teeth and a horny toothless beak. Unlike their relatives the ankylosaurids, these dinosaurs did not have a protective tail club. Nodosaurids have been excavated in North America, Europe, Asia and Australia. They include Hylaeosaurus, Nodosaurus, Panoplosaurus, Sauropelta and Silvisaurus.

Nodosaurus itself was an 18ft long nodosaurid ankylosaur of the Late Cretaceous period, Nodosaurus remains have been excavated in Kansas and Wyoming, USA. Nodosaurus had a narrow snout and no tail club. Examination of a partial jaw found in the Oxford Clay of Petersborough, England, has shown that another species, called Sarcolestes or 'flesh robber' may have been a nodosaurid ankylosaur of the Mid Jurassic period. If this is correct, Sarcolestes would have the honor of being the oldest known nodosaur.

Silvisaurus means 'forest lizard', a name possibly derived from the site where the excavation took place. Silvisaurus was a primitive nodosaurid of the Early Cretaceous period. It was a 13ft long four-legged armored herbivore, excavated in Kansas in the 1960s. This dinosaur had short legs and an elongated body covered in rounded bony plates. Its tail had rounded spikes sticking out from the sides.