Nodosaurus: the armoured browser Wyoming forgot

When and where

Nodosaurus lived during the Late Cretaceous, roughly 100 to 94 million years ago, in what is now Wyoming. Its fossils come from the Frontier Formation, a marine and coastal sedimentary layer that also preserves clams, ammonites, and sea-going reptiles. The environment was a warm shoreline with tidal flats and river deltas feeding into the Western Interior Seaway. No complete skeleton has ever been found, so most estimates rely on fragmentary remains.

How we know

Othniel Charles Marsh named Nodosaurus textilis in 1889, based on vertebrae and armour plates collected near the Powder River in Wyoming. The genus name means "knobbed lizard," a reference to the rounded osteoderms embedded in the skin. The type specimen is incomplete (a partial skeleton with some ribs, vertebrae, and shoulder elements), and no skull has been confidently assigned to the genus. A 1921 redescription by Richard Swan Lull at Yale added more armour fragments and clarified the shoulder girdle, but the animal remains one of the more poorly known ankylosaurs. Source: Wikipedia entry on Nodosaurus.

What set it apart

Unlike its later relative Ankylosaurus, Nodosaurus had no tail club. Its defence was passive: rows of oval osteoderms running in bands across the back and flanks, plus smaller pebble-shaped scutes between them. The body was low and wide, the limbs short and pillar-like, and the head narrow with simple leaf-shaped teeth suited to soft vegetation. Length estimates are uncertain; comparisons with better-known nodosaurids suggest around 4 to 6 metres. The lack of a tail club and the coastal habitat distinguish it from the inland, club-tailed ankylosaurids that came later.

For collectors and classrooms

A Nodosaurus figurine shows the body armour and low stance that define the nodosaurid group. Look for models that include rows of rounded back plates rather than tail-club poses, which belong to Ankylosaurus. Browse a hand-painted figurine.