Torvosaurus
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| Torvosaurus Fossil range: Late Jurassic |
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 Torvosaurus tanneri
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Torvosaurus (pronounced /ˌtɔrvoʊˈsɔrəs/ TOR-vo-SOR-us) is a genus of giant carnivorous dinosaur, relatively similar in appearance to Tyrannosaurus although it had larger 'arms' and a bulky body. It lived about 145 million years ago, in the late Jurassic Period of what is now North America and Portugal. It reached 9 to 11 meters (30 to 36 ft) in length and an estimated weight of about 2 metric tons (2.2 tons), which made it the largest carnivore of its time, except for possibly Epanterias (perhaps just a big Allosaurus) and Saurophaganax.
It was first discovered by James A. Jensen and Kenneth Stadtman in the rocks of the Morrison Formation at the Dry Mesa Quarry, Colorado in 1972. The genus and the type species T. tanneri were named and described in 1979 by Peter M. Galton and Jensen. The name Torvosaurus means 'savage lizard' from the Latin torvus meaning 'savage' and the Greek sauros meaning 'lizard').
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[edit] Material
The holotype is represented by an upper arm bone (humerus) and lower arm bones (radius and ulna). Additional material includes some skull bones, back bones, hip bones and 'hand' bones.
[edit] Systematics
Torvosaurus is related to the earlier Megalosaurus but is seemingly more advanced. Its classification is still uncertain but its family Megalosauridae is most commonly held as a dead-ended branch of basal tetanurae, similar to Ceratosauria, although that group would continue on until the end of the Cretaceous.
[edit] Palaeobiology
Torvosaurus, while the largest predator of the Morrison Formation, was likely not the top predator, instead giving way to the packs of nearly as large Allosaurus that were far more common. The 8m Ceratosaurus also competed for prey, though it likely was a solitary or small group hunter and not much more common than Torvosaurus.
[edit] Largest theropod of the Jurassic
The size of Torvosaurus is not definitely known, because only incomplete material has been found, but it was a large theropod. North American Torvosaurus material is estimated as belonging to an individual about 9.0 meters long (29 ft), with a weight of about 1.95 metric tons (2.15 tons).[1] Material from Portugal indicates even larger animals. In 2006 a nearly complete maxilla found in Portugal was assigned to Torvosaurus tanneri. It measured 63 cm in length (2.13 ft), significantly larger than the 47 cm (1.54 ft) long maxilla of the American specimen (total skull length 118 cm [3.87 ft]). Based on this, a skull length of 158 cm (5.18 ft) was estimated for the Portuguese specimen. This is comparable to the largest T. rex skulls, and makes Torvosaurus the largest known Jurassic theropod (surpassing Saurophaganax/Allosaurus maximus and Edmarka), and among the largest of all theropods. A partial femur from another individual belongs to an animal estimated as 11 m (36 ft) long.[2]
[edit] References
- ^ Paul, Gregory S. (1988). Predatory Dinosaurs of the World. New York: Simon and Schuster, 282. ISBN 978-0671619466.
- ^ Mateus, O., Walen, A., and Antunes, M.T. (2006). "The large theropod fauna of the Lourinha Formation (Portugal) and its similarity to that of the Morrison Formation, with a description of a new species of Allosaurus." New Mexico Museum of Natural History and Science Bulletin, 36.
