Torvosaurus, meaning “savage lizard,” is a genus of large theropod dinosaur from the late Kimmeridgian to early Tithonian stage of the Late Jurassic Period. Fossils of Torvosaurus have been found in North America and Portugal. It was first discovered by James Jensen and Kenneth Stadtman in the Morrison Formation at Dry Mesa Quarry, Colorado in 1972.
The genus and type species, T. tanneri, were named and described by Jensen and Peter M. Galton in 1979. The type specimen was further described by Brooks Britt, and the Portuguese specimen by O. Mateus and M.T. Antunes. The type specimen is represented by an upper arm bone and lower arm bones. Other material includes skull fragments, back bones, hip bones, and hand bones.
Torvosaurus is related to the earlier Megalosaurus but is more advanced. Its classification is uncertain, but it is from the Megalosauridae family and is commonly held as a primitive of Tetanurae, less derived than carnosaurs, and likely related to spinosaurids.
The size of Torvosaurus is not definitely known because of incomplete material recovered. But it is believed to have been a fairly large theropod, reaching 30 to 36 feet in length and weighing about 2.2 tons, which would have made it one of the largest carnivores of its time.
A nearly complete jaw bone was found in 2006 in Portugal that was assigned to Torvosaurus tanneri. It measured 2.13 feet long, much larger than the 1.54-foot long jaw bone of the American specimen. The finding, if confirmed, makes Torvosaurus the largest Jurassic theropod — surpassing Allosaurus and Saurophaganax — and among the largest of all known theropods.