allosaurus [al΄ō sôr′əs, al΄əsôr′əs ]
ModL: see ALLO- & -SAUR
any of a genus (Allosaurus) of huge, carnivorous saurischian dinosaurs of the Jurassic and Cretaceous periods

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Large carnivorous dinosaur of a group similar to the tyrannosaurs, found as fossils primarily in Late Jurassic rocks of North America.

It weighed 2 tons (1,800 kg) and grew to 35 ft (10.5 m) long. Its well-developed tail, half of its total body length, probably functioned as a counterbalance for the body. Allosaurus walked on its two hind limbs and probably used the much smaller forelimbs for grasping. Equipped with powerful, flexible jaws, allosaurs likely preyed on medium-sized dinosaurs; they were possibly scavengers that hunted in groups. Some related allosaurs (Giganotosaurus, Carcharodonotosaurus) may have been larger than Tyrannosaurus rex.

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▪ dinosaur genus
subsumes  Antrodemus  
 large carnivorous dinosaurs that lived from 150 million to 144 million years ago during the Late Jurassic Period; they are best known from fossils found in the western United States, particularly from the Cleveland-Lloyd Quarry in Utah and the Garden Park Quarry in Colorado.

      Allosaurus weighed two tons and grew to 10.5 metres (35 feet) in length, although fossils indicate that some individuals could have reached 12 metres. Half the body length consisted of a well-developed tail, and Allosaurus, like all theropod dinosaurs, was a biped. It had very strong hind limbs and a massive pelvis with strongly forward- (anteriorly) and rearward- (posteriorly) directed projections. The forelimbs were considerably smaller than the hind limbs but not as small as those of tyrannosaurs (tyrannosaur). The forelimbs had three fingers ending in sharp claws and were probably used for grasping.

      The allosaur skull is distinguished by a large roughened ridge just in front of the eye. The skull was large and had sizable laterally compressed teeth, which were sharp and recurved. Allosaurus likely preyed upon ornithischian dinosaurs, small sauropod dinosaurs, and anything else that it could trap and kill. It is possible that Allosaurus was also a scavenger, feeding upon carcasses of dead or dying animals.

      The name Allosaurus subsumes Antrodemus, which was named earlier but was based only on an undiagnostic tail vertebra. Descendants of Allosaurus lived from 144 million to 135 million years ago, during the Early Cretaceous Period, and are known from fossils found in North America, Africa, and Australia.

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Universalium. 2010.

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Look at other dictionaries:

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  • allosaurus — ☆ allosaurus [al΄ō sôr′əs, al΄əsôr′əs ] n. [ModL: see ALLO & SAUR] any of a genus (Allosaurus) of huge, carnivorous saurischian dinosaurs of the Jurassic and Cretaceous periods …   English World dictionary

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  • Allosaurus —  Pour l’article homophone, voir Halosaurus. Allosaurus …   Wikipédia en Français

  • Allosaurus — A. ferox (dudoso) A. fragilis A. lucaris (dudoso) A. tendagurensis (dudoso) Allosaurus (en griego, reptil extraño ) es un género de dinosaurios terópodos, bien conocido por el hallazgo de cientos de fósiles (muchos de ellos esqueletos enteros) en …   Enciclopedia Universal

  • allosaurus — noun Etymology: New Latin, from Greek all + sauros lizard Date: 1886 any of a genus (Allosaurus) of very large carnivorous North American theropod dinosaurs of the late Jurassic period …   New Collegiate Dictionary

  • allosaurus — noun a large, carnivorous dinosaur, of genus Allosaurus, that lived in the Jurassic period …   Wiktionary

  • allosaurus — noun late Jurassic carnivorous dinosaur; similar to but somewhat smaller than tyrannosaurus • Syn: ↑allosaur • Hypernyms: ↑theropod, ↑theropod dinosaur, ↑bird footed dinosaur • Member Holonyms: ↑genus Allosaurus, ↑ …   Useful english dictionary

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