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Dilophosaurus

2007 Schools Wikipedia Selection. Related subjects: Dinosaurs

   iDilophosaurus

                        Fossil range: Early Jurassic

   Dilophosaurus animatronic model
   Dilophosaurus animatronic model

                             Conservation status

   Extinct (fossil)
              Scientific classification

   Kingdom:     Animalia
   Phylum:      Chordata
   Class:       Sauropsida
   Superorder:  Dinosauria
   Order:       Saurischia
   Suborder:    Theropoda
   Superfamily: Coelophysoidea
   Family:      Dilophosauridae
   Genus:       Dilophosaurus
                Welles, 1970

                                   Species

     * D. wetherelli
     * D. breedorum
     *  ?D. sinensis

   Dilophosaurus was a theropod dinosaur from the Early Jurassic Period.
   The name is pronounced (dy-LOH-fo-sawr-us) meaning 'two-crested
   lizard', because it had two crests ( Greek di meaning 'two', lophos
   meaning 'crest' and sauros meaning 'lizard')

Description

   Dilophosaurus measured around 6 meters (20 ft) long and may have
   weighed half a ton. Fossils of the animal have been found at the Navajo
   Indian Reservation, just west of Tuba City, Arizona, USA. Just a few
   tens of feet below the level of the bones, large footprints of
   carnivorous dinosaurs were found and these may belong to Dilophosaurus.
   It lived in the Early Jurassic Period.

   The original description was published in 1954, by the renowned
   paleontologist Samuel Welles. However, at the time, it was thought to
   be another genus of theropod ( Megalosaurus). In 1970, it was
   recognized to be distinct and given its own generic name Dilophosaurus.
   Welles later redescribed the entire taxon in 1984, in a more
   comprehensive paper. Dilophosaurus may be a primitive member of the
   clade containing both ceratosaurian and tetanuran theropods.
   Alternatively, some paleontologists classify this genus as a large
   coelophysoid. Recent Dilophosaurus 'skin imprints', associated with a
   set of footprints, seemed to suggest that it had feathers but further
   study revealed these to be impressions of plant material.

   Footprints of Dilophosaurus have been discovered in the Lavini di Marco
   area, near Rovereto ( Trentino, northern Italy). They are associated
   with those of Camptosaurus.

Skull and crests

   The most distinctive characteristic of Dilophosaurus was the pair of
   rounded crests on its skull, probably used for display. Studies by Rob
   Gay (2001) show that these crests may have been larger in one sex than
   in the other. Another curious skull feature was a notch behind the
   first row of teeth, giving it an almost crocodile-like appearance. This
   "notch" existed by virtue of a weak connection between the premaxillary
   and maxillary bones of the skull. This conformation led to the early
   hypothesis that Dilophosaurus scavenged off dead carcasses, with the
   front teeth being too weak to bring down and hold large prey. A similar
   notch is also present in another Ceratosaur, Syntarsus.

Species

   There is another species of Dilophosaurus (D. sinensis), which may or
   may not belong to this genus. It is possibly closer to the bizarre
   Antarctic theropod Cryolophosaurus, based on the fact that the anterior
   end of the jugal does not participate in the internal antorbital
   fenestra and that the maxillary tooth row is completely in front of the
   orbit and ends anterior to the vertical strut of the lacrimal. This
   species was recovered from the Yunnan Province of China in 1987, with
   the prosauropod Yunnanosaurus and later described and named in 1993 by
   Shaojin Hu.

In popular culture

     * Dilophosaurus featured in the 1993 movie Jurassic Park and in the
       original novel by Michael Crichton (on which the film was based).
       In the film version, it had a retractable frill around its neck
       (much like a frilled lizard), and was able to spit poison, aiming
       for the eyes to blind and paralyse its prey. There is no evidence
       to support this representation, which was invented by the author
       and director to heighten suspense. In the film the director Steven
       Spielberg reduced its size, from moderately large to about 3 feet
       tall and 5 feet long - this was so as not to overshadow the main
       star of the movie, Tyrannosaurus .

     * In the novel, the creature was 10 feet tall with no frill and had
       poisonous saliva that was used in predation by biting or spitting
       at its prey. In the novel, this trait was discovered by the
       researchers at Jurassic Park, who planned to remove the glands
       containing the poison. This plan was not carried out - an autopsy
       would have been needed to see how to remove the glands, but it
       would have required killing a Dilophosaurus, which John Hammond,
       owner of the park, opposed.

     * Dilophosaurus featured in the documentary When Dinosaurs Roamed
       America, killing an Anchisaurus and scaring off a pack of
       Megapnosaurus.

     * Dilophosaurus was also featured in the Vivendi Universal game
       Jurassic Park: Operation Genesis.

     * Dilophosaurus has been featured in the arcade games of The Lost
       World: Jurassic Park and Jurassic Park III but did not appear in
       the movies.

     * The Dilophosaurus in the ParaWorld PC game resembles the one from
       Jurassic Park.

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