Metriacanthosaurus (Greek for "moderate-spined lizard"); pronounced MET-ree-ah-CAN-tho-SORE-us
Woodlands of western Europe
Late Jurassic (160-150 million years ago)
Size and Weight:
About 25 feet long and one ton
Large size; short spines on backbone
Not the most euphoniously named of all dinosaurs, Metriacanthosaurus was mistakenly classified as a species of Megalosaurus when its incomplete fossil was discovered in 1923--not an uncommon occurrence, since many large theropods of the Jurassic period started out under the Megalosaurus umbrella. We still don't know a whole lot about this dinosaur, except that the short spines jutting out from its vertebrae may have supported a slender hump or sail--a hint that Metriacanthosaurus may have been more ancestral to more famous spined carnivores like Spinosaurus.