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Brachiosaurus

2007 Schools Wikipedia Selection. Related subjects: Dinosaurs

          For the extinct amphibian see Branchiosaurus.

   iBrachiosaurus

               Fossil range: Late Jurassic - Early Cretaceous

   Brachiosaurus (Giraffatitan) brancai
   Brachiosaurus ( Giraffatitan) brancai

                             Conservation status

   Extinct (fossil)
                   Scientific classification

   Kingdom:    Animalia
   Phylum:     Chordata
   Class:      Sauropsida
   Superorder: Dinosauria
   Order:      Saurischia
   Suborder:   Sauropodomorpha
   Infraorder: Sauropoda
   Family:     Brachiosauridae
   Genus:      Brachiosaurus
               Riggs, 1903

                                   Species

     * B. altithorax ( type)
     * ?B. ( Giraffatitan) brancai

   Brachiosaurus ( IPA: /ˌbrækiəˈsɔrəs/) meaning "Arm Lizard", from the
   Greek brachion/βραχιων meaning 'arm' and sauros/σαυρος meaning
   'lizard', was a genus of sauropod dinosaur which lived during the Late
   Jurassic Period.

   It was thus named because its forelimbs were longer than its hind
   limbs. One of the largest animals ever to walk the earth, it has become
   one of the most famous of all dinosaurs and is widely recognised
   worldwide.

   For many decades, Brachiosaurus was the largest dinosaur known. It has
   since been discovered that a number of giant titanosaurians (
   Argentinosaurus, for example) surpassed Brachiosaurus in terms of sheer
   mass. More recently, another brachiosaurid, Sauroposeidon, has also
   been discovered; based on incomplete fossil evidence, it too is likely
   to have outweighed Brachiosaurus.

   Brachiosaurus is often considered to be the largest dinosaur known from
   a relatively complete fossilized skeleton. However, the most complete
   specimens, including the Brachiosaurus in the Humboldt Museum of Berlin
   (excavated in Africa, the tallest mounted skeleton in the world), are
   members of the species B. brancai which some scientists consider to be
   part of a separate genus, Giraffatitan. The holotype material of the
   type species, B. altithorax. includes a sequence of seven posterior
   dorsal vertebrae, sacrum, proximal caudal vertebra, coracoid, humerus,
   femur and ribs: enough from which to estimate size.

   Based on a complete composite skeleton, Brachiosaurus attained 25
   metres (82 feet) in length and was probably able to raise its head
   about 13 metres (42 ft) above ground level. Fragmentary material from
   larger specimens indicates that it could grow 15% longer than this.
   Such material includes an isolated fibula HMN XV2 1340 cm in length and
   the brachiosaurid scapulocoracoid referred to Ultrasauros.

   Brachiosaurus has been estimated to have weighed anywhere between 15
   tonnes ( Russell et al. 1980) and 78 tonnes ( Colbert 1962). These
   extreme estimates can be discarded as that of Russell et al. was based
   on limb-bone allometry rather than a body model, and that of Colbert on
   an outdated and overweight model. More recent estimates based on models
   reconstructed from osteology and inferred musculature are in the range
   32 tonnes ( Paul 1988) to 37 tonnes (Christiansen 1997). The 15% longer
   specimens hinted at above would have massed 48 to 56 tonnes.

Discovery and species

   The first Brachiosaurus was discovered in 1900 by Elmer S. Riggs, in
   the Grand River Canyon of western Colorado, in the United States.

Brachiosaurus species

   The front leg bone of a Brachiosaurus.
   Enlarge
   The front leg bone of a Brachiosaurus.

   Brachiosaurus includes three known species:
     * B. alataiensis de Lapparent & Zbyszewski, 1957 has been referred to
       the new genus Lusotitan (Antunes and Mateus 2003). It is known from
       back bones ( vertebrae), and parts of the hip and limbs, which were
       recovered in Estremadura, Portugal. It lived about 150 million
       years ago, during the Kimmeridgian age of the Late Jurassic period.
     * B. altithorax Riggs, 1903: The type species is known from two
       partial skeletons recovered in Colorado and Utah in the United
       States. It lived from 145 to 150 million years ago, during the
       Kimmeridgian to Tithonian ages.
     * ?B. nougaredi de Lapparent, 1960: While it may not be a distinct
       species (nomen dubium?) it is known from set of fused bones over
       the hip ( sacrum) and parts of a forelimb, which were recovered in
       Wargla, Algeria in Africa. It lived 100 to 110 million years ago,
       during the Albian to Cenomanian ages of the middle Cretaceous
       period.

   The best specimens of Brachiosaurus were from the species B. brancai,
   which was found in the Tendaguru Beds of Tanzania, in Africa in 1909 by
   Werner Janensch. In 1991, George Olshevsky placed them in a new genus,
   Giraffatitan, because they do not share the derived characteristics of
   Brachiosaurus. Giraffatitan has withers over its shoulder, and a
   rounded crest over its nostrils.
     * Giraffatitan brancai Janensch, 1914 (formerly B. brancai): The new
       type species, it is known from five partial skeletons, including at
       least three skulls and some limb bones, which were recovered in
       Mtwara, Tanzania, in Africa. It lived from 145 to 150 million years
       ago, during the Kimmeridgian to Tithonian ages of the Late Jurassic
       period.

Description and environment

   Brachiosaurus was a sauropod, one of a group of four-legged,
   plant-eating dinosaurs with long necks and tails and relatively small
   brains. Unlike other families of sauropods, it had a giraffe-like
   build, with long forelimbs and a very long neck. Brachiosaurus had
   spatulate teeth (resembling chisels), well-suited to its herbivorous
   diet. Its skull featured a number of holes, probably aiding
   weight-reduction. The first toe on its front foot and the first three
   toes on its hind feet were clawed.

Skull

   Brachiosaurus has traditionally been characterised by its distinctive
   high-crested skull, but many scientists now assign the specimen which
   this depiction was based on to the genus Giraffatitan.

   One complete Brachiosaurus skull is known. Marsh used it on his early
   reconstructions of Brontosaurus. Carpenter and Tidwell studied it in
   1998 and found that it belonged to one of the North American
   Brachiosaurus species. The skull of Brachiosaurus is more
   camarasaur-like than the distinctive high-crested skull of Giraffatitan
   and it lends support to the opinion that Giraffatitan is a distinct
   genus.

Metabolism

   Like other "long-necked" dinosaurs, Brachiosaurus may not have been
   able to pump sufficient oxygenated blood from its heart to its brain if
   it raised its head high above its shoulders, though this is disputed by
   some researchers.

   If the Brachiosaurus was endothermic (warm-blooded), it would have
   taken an estimated ten years to reach full size. If it were instead
   poikilothermic (cold-blooded), then it would have required over 100
   years to reach full size. As a warm-blooded animal, the daily energy
   demands of Brachiosaurus would have been enormous; it would probably
   have needed to eat more than 400 lb. (~200 kg) of food per day. If
   Brachiosaurus was fully cold-blooded or was a passive bulk endotherm,
   it would have needed far less food to meet its daily energy needs.

Environment and behaviour

   Brachiosaurus at the Dino Jaws exhibition - Natural History Museum,
   London.
   Enlarge
   Brachiosaurus at the Dino Jaws exhibition - Natural History Museum,
   London.

   Brachiosaurus was one of the largest dinosaurs of the Jurassic era; it
   lived on prairies filled with ferns, bennettites, horsetails and it
   moved through vast conifer forests, groves of cycads, Seed ferns, and
   Ginkgos. Some of its contemporary genera included Stegosaurus,
   Dryosaurus, Apatosaurus, and Diplodocus. While it is speculated that
   groups of Brachiosaurus moved in herds, fully grown individuals had
   little to fear from even the largest predators of the time, Allosaurus
   and Torvosaurus, on account of their sheer size.

   Brachiosaurus nostrils, like the huge corresponding nasal openings in
   its skull, were long thought to be located on the top of the head. In
   past decades, scientists theorised that the animal used its nostrils
   like a snorkel, spending most of its time submerged in water in order
   to support its great mass. The current consensus view, however, is that
   Brachiosaurus was a fully terrestrial animal. Studies have demonstrated
   that water pressure would have prevented the animal from breathing
   effectively while submerged and that its feet were too narrow for
   efficient aquatic use. Furthermore, new studies by Larry Witmer (2001)
   show that, while the nasal openings in the skull were placed high above
   the eyes, the nostrils would still have been close to the tip of the
   snout (a study which also lends support to the idea that the tall
   "crests" of brachiosaurs supported some sort of fleshy resonating
   chamber).

Berlin's G. brancai and Chicago's high flyer

   A Brachiosaurus skeleton is mounted in the B Concourse of United
   Airlines' Terminal One in O'Hare International Airport in Chicago,
   courtesy of the Field Museum of Natural History of Chicago. It is a
   model, not a collection of fossils.

   A famous specimen of Giraffatitan brancai mounted in Berlin, sometimes
   considered a species or sub-genus of Brachiosaurus, is one of the
   largest mounted skeletons in the world.

   Beginning in 1909, Werner Janensch found many additional brachiosaur
   specimens in Tanzania, Africa, including some nearly complete
   skeletons, which were widely used in Brachiosaurus reconstructions.
   These are now considered to be Giraffatitan fossils.

In popular culture

   Brachiosaurus appeared in two of the three Jurassic Park movies. In the
   first movie they are seen when the scientists land on the island.
   Later, the herd interacts with some people in a tree. In Jurassic Park
   III, another herd is seen on Isla Sorna, first from the view of an
   airplane and later from a boat.

   Brachiosaurus is also featured in the Vivendi Universal game, Jurassic
   Park: Operation Genesis.

   Brachiosaurus appeared in the Walt Disney movie Dinosaur. Only one was
   shown, an older female who was the last of her kind.

   Brachiosaurus appeared briefly in the second episode of Walking with
   Dinosaurs to show the great achievements of sauropods.

   There were two brachiosaurs in the Power Rangers series. The first was
   the Carrierzord Titanus in Mighty Morphin Power Rangers season 1, who
   also appeared three times in season 3. It also provided the power
   source for the Black Ranger in Power Rangers: Dino Thunder and, like
   its MMPR counterpart, functioned as a sort of carrier, providing
   transportation to the other Dinozords in its bulky body.
   Retrieved from " http://en.wikipedia.org/wiki/Brachiosaurus"
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