Scutellosaurus (Greek for "little shield lizard"); pronounced SKOO-tell-oh-SORE-us
Woodlands of southern North America
Early Jurassic (200-195 million years ago)
Size and Weight:
About 4 feet long and 25 pounds
Small size; long tail; bony studs on back
One of the persistent themes of evolution is that large, imposing creatures descend from small, mouselike progenitors. Although no one would think of comparing Scutellosaurus to a mouse (it weighed about 25 pounds, for instance, and was covered with bony spikes), this dinosaur was certainly rodent-sized compared to its multi-ton armored descendants of the late Cretaceous period, such as Ankylosaurus and Euoplocephalus.
Although its hind limbs were longer than its forelimbs, paleontologists believe Scutellosaurus was ambidextrous, posture-wise: it probably stayed on all fours while eating, but was capable of breaking into a two-legged gait when escaping predators. Like other early dinosaurs, Scutellosaurus was anatomically very similar to the prosauropods and small theropods that roamed the earth during the late Triassic and early Jurassic periods.