Monolophosaurus was a medium sized theropod dinosaur (about 16 feet long) that lived during the Middle Jurassic Period (about 165 million years ago) in what is now China. It had a distinctive crest running the length of its snout, which is recreated on this Monolophosaurus toy. History: The first Monolophosaurus skeleton was discovered by a joint Canadian-Chinese expedition to Xinjiang Province of China in 1981. Although a few more partial skeletons have been found, Monolophosaurus remains a rare dinosaur. Scientific Name: Monolophosaurus, meaning single-crested lizard. Characteristics: The most conspicuous characteristic of Monolophosaurus is the single crest on the top of the animal's head. Although Monolophosaurus looks a bit like the more famous Tyrannosaurus rex, it is much smaller and more primitive. Size: This Monolophosaurus toy is 7.5 inches long and 3 inches high.