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Allosaurus

2007 Schools Wikipedia Selection. Related subjects: Dinosaurs

                             iAllosaurus
   Replica of Allosaurus skull (San Diego Natural History Museum).
   Replica of Allosaurus skull (San Diego Natural History Museum).

                             Conservation status

   Extinct (fossil)
                      Scientific classification

   Kingdom:    Animalia
   Phylum:     Chordata
   Class:      Sauropsida
   Superorder: Dinosauria
   Order:      Saurischia
   Suborder:   Theropoda
   Infraorder: Carnosauria
   Family:     Allosauridae
   Genus:      Allosaurus
               Marsh, 1877

                                   Species

     * A. fragilis type
     * A. atrox ( Marsh, 1878) Paul, 1987
     * A. "jimmadseni" Chure, 2000 vide Glut, 2003

                              Synonyms

     * Creosaurus Marsh, 1878
     * Labrosaurus Marsh, 1879
     * Camptonotus Marsh, 1879
     *  ? Antrodemus Leidy, 1870
     *  ? Epanterias Cope, 1878
     *  ? Saurophaganax Chure, 1995

   Allosaurus ( IPA: [ˈæləˌsɔɹəs]) was a large bipedal carnivorous
   dinosaur up to 12  m (39  ft) long. It was named 'different lizard'
   because its vertebrae were different from those of all other dinosaurs.
   The name comes from the Greek allos/αλλος, meaning 'strange' or
   'different' and saurus/σαυρος, meaning 'lizard' or 'reptile'. It was
   the most common large predator in what is now North America, 155 to 145
   million years ago, in the late Jurassic period. It shared the landscape
   with several genera of giant sauropods such as Apatosaurus, Diplodocus
   and Camarasaurus as well as other herbivores such as Stegosaurus and
   Camptosaurus, all of which may have been potential prey.

   More scant finds of a smaller species similar to Allosaurus and dating
   from the Early Cretaceous of North America and Australia, indicate that
   this versatile hunter might have survived the mass extinction at the
   end of the Jurassic, 144 MYA. Fukuiraptor from the Early Cretaceous of
   Japan has been shown to be an allosaurid and may be the same animal as
   the Australian Allosaurus.

Description

   A replica Allosaurus skeleton in Canterbury Museum, Christchurch, New
   Zealand. The current view is that the animal normally stood in a more
   horizontal position.
   Enlarge
   A replica Allosaurus skeleton in Canterbury Museum, Christchurch, New
   Zealand. The current view is that the animal normally stood in a more
   horizontal position.

   Allosaurus was a typical large theropod, having a massive skull on a
   short neck, a long tail and reduced forelimbs, with an average length
   of ~9 meters (~30 feet). Its most distinctive feature was a pair of
   blunt horns, just above and in front of the eyes. Although short in
   comparison to the hindlimbs, the forelimbs were massive and bore large,
   eagle-like claws. The skull showed evidence of being composed of
   separate modules, which could be moved in relation to one another,
   allowing large pieces of meat to be swallowed. The skeleton of
   Allosaurus, like other theropods, displayed bird-like features, such as
   a furcula (wishbone) and neck vertebrae hollowed by air sacs.

Finds

   Allosaurus is the most common theropod in the vast tract of
   dinosaur-bearing rock in the American Southwest known as the Morrison
   Formation. Remains have been recovered in Montana, Wyoming, South
   Dakota, Colorado, Oklahoma, New Mexico and Utah, in the United States.
   There have also been finds in Portugal. Allosaurus shared the Jurassic
   landscape with several other theropods, including Ceratosaurus and the
   massive Torvosaurus.
   Allosaurus skull from Dinosaur National Monument, still partially
   encased in matrix.
   Enlarge
   Allosaurus skull from Dinosaur National Monument, still partially
   encased in matrix.

   A famous fossil bed can be found in the Cleveland Lloyd Dinosaur Quarry
   in Utah. This fossil bed contains over 10,000 bones, mostly of
   Allosaurus, intermixed with the remains of other dinosaurs, such as
   Stegosaurus and Ceratosaurus. It is still a mystery how the remnants of
   so many animals can be found in one place. The ratio of fossils of
   carnivorous animals over fossils of plant eaters is normally very
   small. Findings like these can be explained by pack hunting, although
   this is difficult to prove. Another possibility is that the Cleveland
   Lloyd site formed a ' predator trap', similar to the La Brea Tar Pits,
   that caused large numbers of predators to become mired in an
   inescapable sediment.

"Big Al"

   One of the more significant finds was the 1991 discovery of " Big Al"
   (MOR 593), a 95% complete, partially articulated, juvenile specimen
   that measured 8 meters (26 feet) in length. Nineteen bones were broken
   or showed signs of infection, which probably contributed to Big Al's
   death. It was featured in "The Ballad of Big Al", a special programme
   in the BBC's Walking with Dinosaurs series. The fossils were excavated
   near Shell, Wyoming by the Museum of the Rockies and the University of
   Wyoming Geological Museum. This skeleton was initially discovered by a
   Swiss team, led by Kirby Siber. The same team later excavated a second
   Allosaurus, "Big Al Two", which is the best preserved skeleton of its
   kind to date.

Classification and history

   The first Allosaurus fossil to be described was a 'petrified horse
   hoof' given to Ferdinand Vandiveer Hayden in 1869, by the natives of
   Middle Park, near Granby, Colorado. It was actually a caudal vertebra
   (a tail bone), which Joseph Leidy tentatively assigned first to the
   Poekilopleuron genus and later to a new genus, Antrodemus. However, it
   was Othniel Charles Marsh who gave the formal name Allosaurus fragilis
   to the genus and type species in 1877, based on much better material,
   including a partial skeleton, from Garden Park, north of Canon City,
   Colorado.

   The species epithet fragilis is Latin for 'fragile'. Both refer to
   lightening features in the vertebrae.

   It is unclear how many species of Allosaurus there were. The material
   from the Cleveland Lloyd Dinosaur Quarry specimen is much smaller and
   more lightly-built than the huge and robust Allosaurus from Brigham
   Young University's Dry Mesa Quarry. Fossils resembling Allosaurus have
   been described from Portugal.

Allosaurid relatives

     * Fukuiraptor is an early Cretaceous theropod from Japan thought to
       be an Allosaurid.

     * An allosaurid astragalus (ankle bone) was found at Cape Patterson,
       Victoria in early Cretaceous beds in Southeastern Australia. This
       is notable as this part of Australia lay within the Antarctic
       Circle at the time.

In popular culture

   Allosaurus is the official state fossil of Utah, in the United States.

   Along with Tyrannosaurus, Allosaurus has come to represent the
   quintissential carnivorous dinosaur in popular culture. Allosaurus has
   featured in the following films:

   Allosaurus is top predator in both Arthur Conan Doyle's novel, The Lost
   World, and the 1925 film adaptation (not to be confused with
   Tyrannosaurus).

   One Million Years BC

   The Valley of Gwangi (Gwangi is technically meant to be an Allosaurus
   but Ray Harryhausen based his model for the creature on Tyrannosaurus.
   Harryhausen often confuses the two, stating in a DVD interview "They're
   both meat eaters, they're both Tyrants... one was just a bit larger
   than the other.")

   The main hero of Dinosaucers, "Allo", is an evolved Allosaurus.

   Fran Sinclair of Dinosaurs (TV series) is mentioned on the show and a
   number of merchandise packaging as being an Allosaurus.

   An Allosaurus named Santo was the main character of an Age of Reptiles
   comic, The Hunt. He was pitted against a pack of Ceratosaurus.

   Calvin in the comic strip Calvin and Hobbes often imagines himself as
   an Allosaurus in his "dinosaur" fantasies.

   It appears in the second and fifth episodes of Walking with Dinosaurs.
   As the main enemy of Diplodocus in the second episode, one injures the
   main character, a female, by taking a deep bite out of her back. A
   dwarf species appears in the fifth episode, as the main predator of
   Leaellynasaura, killing and eating the leading Leaellynasaura female.

   The Walking With Dinosaurs special The Ballad of Big Al chornicles the
   life of Big Al.

   Allosaurus appear in When Dinosaurs Roamed America, killing a
   Ceratosaurus and feasting on a wounded Apatosaurus.

   Allosaurus appears in the children's television series Land of the Lost
   (1974 TV series) 1974-1976.
   Retrieved from " http://en.wikipedia.org/wiki/Allosaurus"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
