Scutellosaurus, meaning “little-shielded lizard,” is a genus of herbivorous dinosaur from the Early Jurassic Period of what is now North America (200 to 196 million years ago). It is classified in the sub-order Thyreophora, which include armored dinosaurs. Its closest relative may have been Scelidosaurus, which, unlike the bipedal Scutellosaurus, was mainly quadrupedal. It was one of earliest representatives of Thyreophora.
Fossil evidence includes two partial skeletons recovered from Arizona. The dinosaur had several hundred scutes (shields or plates) running along its neck and back as far down as its tail. Some of these scutes were flat, while others were pitted. The tail was unusually long, possibly to provide counterbalance against the weight of its armored body. It had long arms, suggesting it may have browsed on all fours.
Scutellosaurus was about 3.9 feet long, 20 inches tall at the hips, and weighed approximately 22 pounds in adulthood.