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Iguanodon

2007 Schools Wikipedia Selection. Related subjects: Dinosaurs

                              iIguanodon
   Iguanodon skull from Oxford University Museum of Natural History
   Iguanodon skull from Oxford University Museum of Natural History

                             Conservation status

   Extinct (fossil)
                      Scientific classification

   Kingdom:    Animalia
   Phylum:     Chordata
   Class:      Sauropsida
   Superorder: Dinosauria
   Order:      Ornithischia
   Suborder:   Ornithopoda
   Infraorder: Iguanodontia
   Family:     Iguanodontidae
   Genus:      Iguanodon
               Mantell, 1825

                                   Species

     * I. bernissartensis ( neotype)

   Iguanodon (meaning " Iguana tooth") is the name given to a genus of
   ornithopod dinosaurs, which lived roughly halfway between the early
   hypsilophodontids and their ultimate culmination in the duck-billed
   dinosaurs. They lived between 120 to 140 million years ago, in the
   Barremian to Valanginian ages of the Early Cretaceous Period, although
   one dubious species is from the Late Jurassic. Iguanodon's most
   distinctive feature was a large razor-sharp 'thumb spike', probably
   used for defense against predators.

   Iguanodon was the first dinosaur recognized and the second dinosaur
   formally named, described in 1822 by English geologist Gideon Mantell.
   Together with Megalosaurus and Hylaeosaurus, it was one of the three
   originally used to define the new classification, Dinosauria.

Paleobiology

   The various Iguanodon species are bulky herbivores, ranging from 6 to
   11 metres (20 to 36 feet) in length, and averaging about 5 tonnes (5.5
   tons) in weight. Iguanodon's thumb spikes were perpendicular to the
   three main digits. In early restorations, the spike was placed on the
   animal's nose. Later fossils revealed the true nature of the thumb
   spikes, although their exact purpose is still debated. It could have
   been used for defence, or for foraging for food.

Posture

   Early fossil remains were fragmentary, which led to much speculation on
   the posture and nature of Iguanodon. Initially, Iguanodon was portrayed
   as a quadrupedal horn-nosed beast, in the mid-19th century. However as
   more bones were discovered, Mantell astutely observed that the
   forelimbs were much smaller than the hindlimbs. His rival Owen was of
   the opinion it was a stumpy creature with four pillar-like legs. The
   job of overseeing the first life size reconstruction of dinosaurs was
   initially offered to Mantell, who declined due to ill-health, and
   Owen's vision subesequently formed the basis on which the sculptures
   took shape.

   Then, with the discovery of the Bernissart skeletons, its bipedal
   nature was revealed. However, it was depicted in an upright posture,
   with the tail dragging along the ground, acting as the third leg of a
   tripod. Since then, however, it has been depicted in a more horizontal
   though predominantly bipedal posture, with stiffened tail.
   Paleontologist David Norman proposes that mature Iguanodons may have
   been quadrupedal.

   Benjamin Waterhouse Hawkins-designed Iguanodon statues, at Crystal
   Palace, based on the theories of Sir Richard Owen

   Reconstruction by Samuel Griswold Goodrich from Illustrated Natural
   History of the Animal Kingdom

   Reconstruction as biped in old ' tripod' posture from early 20th cent.

   Current reconstruction, with more horizontal bipedal posture.

Discovery and species

   Iguanodon model Oxford University Museum of Natural History
   Enlarge
   Iguanodon model Oxford University Museum of Natural History
   Iguanodon hind feet Oxford University Museum of Natural History
   Enlarge
   Iguanodon hind feet Oxford University Museum of Natural History

   The story goes that Gideon Mantell's wife, Mary Ann, discovered the
   first tooth of an Iguanodon in the strata of Tilgate Forest in
   Cuckfield, Sussex, England, in 1822 while Mantell was visiting a
   patient. The tooth resembled that of an iguana, but was twenty times
   larger, so he named it Iguanodon or "iguana-toothed", from iguana and
   the Greek word odontos (" tooth"). His initial idea for a name was
   Iguanasaurus, however his friend Conybeare suggested the name was
   applicable to the iguana lizard itself, so a better name would be
   Iguanoides ("Iguana-like") or Iguanodon.

   Based on isometric scaling, he estimated that the creature might have
   been up to 60 feet (18 metres) long. A better specimen was discovered
   in a quarry in Maidstone, Kent, England, which Mantell was able to
   identify, after acquiring it in 1834, as an Iguanodon, based on the
   tooth. The Maidstone slab allowed the first skeletal reconstructions
   and artistic renderings of the Iguanodon. The most famous mistake was
   the placement of a " horn", also discovered by Mantell's wife, on the
   nose of the dinosaur. The discovery of much better specimens of I.
   bernissartensis in 1878 in Belgium revealed that the horn was actually
   a modified thumb, perhaps used for defense.

   Still encased in rock, the Maidstone slab is currently displayed at the
   Natural History Museum, in London. The borough of Maidstone
   commemorated this find by adding an Iguanodon to their coat of arms, in
   1949.

   I. anglicus was the original type species but the holotype was based on
   a single tooth and only partial remains of the species have been
   recovered since. In March of 2000, the International Commission on
   Zoological Nomenclature changed the type species to I. bernissartensis,
   which is known from dozens of skeletons found in Benissart (see below),
   some of which are very complete.
   Sculpture outside the museum of the Royal Belgian Institute of Natural
   Sciences, Brussels
   Enlarge
   Sculpture outside the museum of the Royal Belgian Institute of Natural
   Sciences, Brussels

   Remains of the best-known Iguanodon species have been found
   predominantly in Belgium, England, Germany, Spain and France. Remains
   of similar animals have been found in Tunisia and Mongolia, and
   distinct species have been found in Utah and South Dakota.

   The largest find of Iguanodon remains occurred in 1878 in a coal mine
   at Bernissart in Belgium. With the encouragement of Alphonse Briart,
   supervisor of mines at nearby Morlanwelz, Louis Dollo oversaw
   excavation and reconstructed the skeletons. Some were publicly
   displayed from 1882. The completed restoration makes an impressive
   display in the Royal Belgian Institute of Natural Sciences, in
   Brussels. A replica of one of these is on display at the Oxford
   University Museum of Natural History. The original Iguanodon tooth is
   held at Te Papa Tongarewa, the Museum of New Zealand in Wellington,
   although it is not on display.

   In 1989, I. lakotaensis was described based on a partial skull from
   Early Cretaceous beds in South Dakota.

Iguanodon Species

     * I. bernissartensis ( neotype)
     * I. anglicus ( holotype)
     * I. atherfieldensis
     * I. dawsoni
     * I. fittoni
     * I. hoggi
     * I. lakotaensis

   A previously named species, Iguanodon orientalis was renamed Altirhinus
   kurzanovi in 1998.

Classification

   Iguanodon gives its name to the infraorder Iguanodontia, a very
   populous group with many species of Ornithopod from the mid-Jurassic to
   the Late Cretaceous.

In popular culture

     * Iguanodon appeared in the BBC Walking with Dinosaurs production.
     * In Disney's film, Dinosaur, an Iguanodon named Aladar served as the
       protagonist with three other iguanadons as other main characters.
     * Iguanodon played a starring role in Sir Arthur Conan Doyle's book,
       "The Lost World".
     * Iguanodon is one of the three dinosaur species which inspired
       Godzilla, the other two being Tyrannosaurus and Stegosaurus.

     * Iguanodon made appearances in the sequels of The Land Before Time.

   Retrieved from " http://en.wikipedia.org/wiki/Iguanodon"
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   with only minor checks and changes (see www.wikipedia.org for details
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