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Therizinosaurus

2007 Schools Wikipedia Selection. Related subjects: Dinosaurs

   iTherizinosaurus

                        Fossil range: Late Cretaceous

                  Conservation status

   Extinct (fossil)
               Scientific classification

   Kingdom:    Animalia
   Phylum:     Chordata
   Class:      Sauropsida
   Superorder: Dinosauria
   Order:      Saurischia
   Suborder:   Theropoda
   Infraorder: Coelurosauria
   Family:     Therizinosauridae
   Genus:      Therizinosaurus
   Species:    T. cheloniformis

                                Binomial name

   Therizinosaurus cheloniformis
   Maleev, 1954

   Therizinosaurus ('scythe lizard', from the Greek therizo meaning 'to
   reap' or 'to cut off' and sauros meaning 'lizard') was a very large
   therizinosaur (previously known as segnosaur). It could grow up to
   10-12 meters (33-40 feet) long and reach 3-6 tons in weight.
   Therizinosaurus lived in the late Cretaceous Period around 70-75
   million years ago, and was one of the later and largest representatives
   of its unique group. Its fossils were first discovered in Mongolia and
   when it was discovered it was originally thought to be a turtle (hence
   the name cheloniformis - turtle-formed) but it is now accepted as a
   maniraptoran theropod dinosaur.

Discovery and Species

   The first fossils now attributed to Therizinosaurus were discovered in
   the late 1940s by a joint Soviet-Mongolian fossil expedition. The
   expedition unearthed several giant claws which measured up to a meter
   in length - but to what creature these belonged was unknown until the
   early 1950s, when further fossil expeditions unearthed more bones -
   several more sets of claws and parts of a forelimb and hindlimb.
   Subsequent finds in northern China allowed paleontologists to assemble
   the general skeletal structure of the animal, which was determined to
   be a dinosaur and not a turtle. In 1954, the animal was named
   Therizinosaurus ('scythe lizard'), referring to the enormous claws. At
   present, there is one accepted species - T. cheloniformis.

   The recent discovery of several related dinosaurs - Alxasaurus in 1993
   and Beipiaosaurus in 1996 - helped clarify the position of the
   therizinosaurs as a whole. Various theories had been proposed to
   explain the ancestry of these dinosaurs, with some scientists even
   suggesting they were descendents of the sauropodomorphs - but these
   new, well-preserved finds, giving details about the bird-like pelvis,
   feet and skulls, helped confirm that the therizinosaurs were all
   maniraptoran, theropod dinosaurs.

Characteristics

   Therizinosaurus had a small head with a beaked mouth, atop a long neck.
   It was bipedal and had a large, heavy, deep body, as evidenced by the
   wide pelvis, 2.5 meter (8 foot) long 'arms' and hind legs that ended in
   four toes (three of which supported the animal's weight), which were
   tipped by short, curved claws. The most distinctive feature of the
   animal was the presence of three gigantic claws on its front limbs.
   Each of the three digits of its 'hand' bore these claws, which reached
   nearly a meter (approximately 2-3 feet) in length. The largest claw was
   on the first digit.

   The feeding habits of Therizinosaurus are still debated, but it was
   most probably an herbivore, using its big claws to push leaves into its
   mouth. Other hypotheses suggest that it was a termite eater, using its
   claws to open large termite nests - but it seems highly unlikely that
   an animal the size of Therizinosaurus could survive on a diet based on
   insects and features of the skull (including a beaked mouth and
   flattened teeth) suggest a herbivorous diet . It is thought that
   Therizinosaurus lived a similar lifestyle to modern gorillas or
   prehistoric ground sloths, using its long arms and sharp claws to grab
   food and foliage from trees.

   There are other possible functions that could have been served by the
   claws of Therizinosaurus, such as defense against predators (e.g. the
   contemporary Tarbosaurus) and in intraspecific fighting, such as
   fighting for territory or for mating. The claws may even have served
   all these functions.

   It is highly likely that Therizinosaurus was feathered, given that its
   close relative Beipiaosaurus certainly was.

In popular culture

   Therizinosaurus appeared in the BBC Walking With Dinosaurs special
   "Chased By Dinosaurs".

   Therizinosaurus appears in the Playstation video game Dino Crisis. In
   the game, Therizinosaurus is portrayed as an active predator rather
   than a herbivore.
   Retrieved from " http://en.wikipedia.org/wiki/Therizinosaurus"
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   with only minor checks and changes (see www.wikipedia.org for details
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