Scelidosaurus (H. Kyoht Luterman).


Scelidosaurus (Greek for "rib of beef lizard"); pronounced SKEH-lih-doe-SORE-us


Woodlands of western Europe and southern North America

Historical Period:

Early Jurassic (208-195 million years ago)

Size and Weight:

About 11 feet long and 500 pounds



Distinguishing Characteristics:

Bony plates and spines on back; quadrupedal posture; horny beak

About Scelidosaurus

As dinosaurs go, Scelidosaurus has a fairly deep provenance, popping up in the fossil record at the start of the Jurassic period, 208 million years ago, and persisting for the next 10 or 15 million years. In fact, this plant-eater was so "basal" in its features that paleontologists speculate it may have given rise to the family of dinosaurs, the thyreophorans, or "armor-bearers," that included both the ankylosaurs (typified by Ankylosaurus) and stegosaurs (typified by Stegosaurus) of the later Mesozoic Era. Certainly, Scelidosaurus was a well-armored beast, with three rows of bony "scutes" embedded in its skin and tough, knobby growths on its skull and tail.

Whatever its place on the thyreophoran family tree, Scelidosaurus was also one of the first ornithischian ("bird-hipped") dinosaurs, a family that included pretty much all of the highly specialized, herbivorous dinosaurs of the Jurassic and Cretaceous periods, with the exception of sauropods and titanosaurs. Some ornithischians were bipedal, some were quadrupedal, and some were capable of walking on both two and four legs; although its hind limbs were longer than its forelimbs, paleontologists speculate that Scelidosaurus was a devoted quadruped.

Scelidosaurus has a complicated fossil history. The type specimen of this dinosaur was discovered in Lyme Regis, England, in the 1850's, and forwarded to the famous naturalist Richard Owen, who accidentally erected the genus name Scelidosaurus ("rib of beef lizard") instead of the Greek construction he intended ("lower hind limb lizard"). Perhaps embarrassed by his mistake, Owen promptly forgot all about Scelidosaurus, even though its quadrupedal posture would otherwise have confirmed his early theories about dinosaurs. It was up to Richard Lydekker, a generation later, to pick up the Scelidosaurus baton, but this eminent scientist committed his own blunder, mixing up the bones of an additional fossil specimens with those of an unidentified theropod, or meat-eating dinosaur!