Allosaurus

      Allosaurus Dinosaur (AL-oh-sore-us) was a big carnivorous dinosaur with a length of up to 12 m (39 ft).It was the most common huge predator in North America, 140 million years ago, in the Jurassic period.

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

      Allosaurus is a classic big theropod: a big skull on a short neck, a long tail, and abridged forelimbs. Its most distinctive feature is a pair of blunt horns just above and in front of the eyes. Although short in assessment to the hindlimbs, the forelimbs are massive and bear large, eagle-like claws. The skull shows evidence of being self-possessed of separate modules, which could be moved in relation to one another, allowing big pieces of meat to be swallowed. The skeleton of Allosaurus, like other theropods, shows birdlike features similar to a wishbone and neck vertebrae hollowed by air sacs. It is thought that Allosaurus might have necessary in packs, allowing it to bring down the huge sauropods of the time.

Findings

     Allosaurus Dinosaur is the most general theropod in the huge section of dinosaur-bearing rock in the American Southwest known as the Morrison Formation. Remains have been improved in Montana, Wyoming, South Dakota, Colorado, Oklahoma, New Mexico, and Utah in the United States; and in Portugal. Curiously, Allosaurus shared the Jurassic landscape with several other theropods, including Ceratosaurus and the massive Torvosaurus.

     A famous fossil bed can be found in the Cleveland Lloyd Quarry in Utah. This fossil bed contains over 10,000 bones, mostly of Allosaurus, with other dinosaurs like Stegosaurus and Ceratosaurus thrown in. It is still a mystery how the bits and pieces of so many animals can be found in one place: normally the ratio of fossils of carnivorous animals over fossils of plant eaters is very small. Conclusion like these can be explained by pack hunting, although this is difficult to prove.

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

Classification and history of Allosaurus Dinosaur

    The first Allosaurus Dinosaur fossil to be described was a "petrified horse hoof" given to Ferdinand Vanpeer Hayden in 1869 by the populace of Middle Park, near Granby, Colorado. It was really a caudal vertebra (a tail bone), which Joseph Leidy tentatively assigned first to the Poicilopleuron 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 counting a partial skeleton, from Garden Park, north of Canon City, Colorado.

    The name Allosaurus Dinosaurs comes from the Greek allos, meaning "strange" or "different"; and sauros, meaning "lizard" or "reptile". The species epithet fragilis is Latin for "fragile". Both refer to lightening skin in the vertebrae.

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

   Allosaurus's closest relative is probably the Lower Cretaceous Acrocanthosaurus.

 Allosaurus facts:
Name:     Allosaurus Dinosaur (AL-oh-sore-us)
Size:     39 feet long and 12 feet tall
Main Facts:     It is unclear how many species of Allosaurus Dinosaurs there were. Fossils like Allosaurus have been described from Portugal.