Difference between revisions of "Brachiosaurus" - New World Encyclopedia

From New World Encyclopedia
 
(14 intermediate revisions by 5 users not shown)
Line 1: Line 1:
−
{{Contracted}}
+
{{Paid}}{{Approved}}{{Images OK}}{{Submitted}}{{copyedited}}
−
:''For the prehistoric amphibian see [[Branchiosaurus]]''.
 
 
{{Taxobox
 
{{Taxobox
 
| color = pink
 
| color = pink
 
| name = ''Brachiosaurus''
 
| name = ''Brachiosaurus''
 
| status = fossil
 
| status = fossil
−
| fossil_range = [[Late Jurassic]] - [[Early Cretaceous]]
+
| fossil_range = Late [[Jurassic]] - Early [[Cretaceous]]
 
| image = Brachiosaurus-brancai_jconway.jpg
 
| image = Brachiosaurus-brancai_jconway.jpg
 
| image_width = 200px
 
| image_width = 200px
Line 21: Line 20:
 
| subdivision_ranks = Species
 
| subdivision_ranks = Species
 
| subdivision =  
 
| subdivision =  
−
* ''B. altithorax'' ([[Type species|type]])
+
* ''B. altithorax'' ([[Genus#Type species|type]])
−
* ''?B. ([[Giraffatitan]]) brancai''
+
* ''B. ([[Giraffatitan]]) brancai''
 +
* ''B. nougaredi''  
 
}}
 
}}
  
−
'''''Brachiosaurus''''' ("arm lizard," from the Greek ''brachion''/βραχιων meaning "arm" and ''sauros''/σαυρος meaning "lizard") was a [[genus]] of huge, [[sauropod]] [[dinosaur]]s that lived during the late [[Jurassic]] period. Sauropods (Sauropoda) is a suborder or infraorder of the saurischian, "lizard-hipped" dinosaurs, and in generally these were large, relatively small-headed herbivorous dinosaurs. ''Brachiosaurus'' was named because its forelimbs were longer than its hind limbs. ''Brachiosaurus'' has become one of the most famous groups of all dinosaurs and is widely recognised worldwide.  
+
'''''Brachiosaurus''''' is an extinct [[genus]] of huge, [[sauropod]] [[dinosaur]]s that lived during the late [[Jurassic]] period. Sauropods comprise a suborder or infraorder of the [[saurischian]] ("lizard-hipped") dinosaurs, and in general were large, herbivorous dinosaurs. ''Brachiosaurus,'' which means "arm lizard," (from the Greek ''brachion''/βραχιων meaning "arm" and ''sauros''/σαυρος meaning "lizard") was so-named because the forelimbs were longer than the hind limbs. ''Brachiosaurus'' has become one of the most famous groups of all dinosaurs and is widely recognized worldwide.  
  
−
''Brachosaurus'', whose members are known as brachiosaurs, is a genus in the Brachiosauridae family, whose members are known as brachiosaurids.  The brachiosaurs were among the largest animals ever to walk the earth.
+
Brachiosaurus represented one stage in the history of [[life]]. When the age of dinosaurs was over, it gave rise to a new stage that prepared the foundation for the modern earth, with the ascension of [[mammal]]s and [[bird]]s. For young earth [[creationism|creationists]] (YEC), the presence of dinosaurs such as ''Brachiosaurus'' represents a problem, for their appearance 150 millions years ago conflicts with the YEC's belief in an Earth only thousands of years old. But for most religious adherents, there is no conflict between their religious beliefs and an Earth billions of years old, which passed through various stages leading to the appearance of [[human being]]s.  
  
 +
''Brachiosaurus,'' whose members are known as brachiosaurs, is a genus in the Brachiosauridae family, whose members are known as brachiosaurids.  The brachiosaurs were among the largest animals ever to walk the earth. 
  
−
==Size==
+
==Description and environment==
 +
''Brachiosaurus'' was a [[sauropod]] (Sauropoda), a group of large, four-legged, plant-eating, dinosaurs with long necks, relatively small heads and [[brain]]s, and generally long tails. Unlike other sauropods, ''Brachiosaurus'' 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 feet and the first three toes on its hind feet were clawed.
  
−
For many decades, the brachiosaurs were the largest dinosaurs known. It has since been discovered that a number of giant titanosaurians (''Argentinosaurus'', for example) surpassed brachiosaurs in terms of sheer mass. More recently, another member of the same family, Brachiosauridae, but another genus, ''Sauroposeidon'', has been discovered that seems likely to have outweighted the known brachiosaurs, albeit on incomplete fossil evidence.
+
''Brachiosaurus'' traditionally had been characterized by its distinctive high-crested skull, but many scientists now assign the specimen which this depiction was based on to the genus ''Giraffatitan.''
  
−
''Brachiosaurus'' is often considered to be the largest [[dinosaur]] known from a relatively complete [[fossil]]ized 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 ''Brachiosaurus brancai'' which some scientists consider to be part of a different [[genus]], ''Giraffatitan''. The holotype material of the type species, ''Brachiosaurus altithorax'', includes a sequence of seven posterior dorsal vertebrae, sacrum, proximal caudal vertebra, coracoid, humerus, femur and ribs—enough from which to estimate size.
+
One complete ''Brachiosaurus'' skull is known. [[O. C. Marsh]] used it on his early reconstructions of ''[[Apatosaurus]].'' 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 ''[[Camarasaurus|camarasaur]]''-like than the distinctive high-crested skull of ''Giraffatitan'' and it lends support to the opinion that ''Giraffatitan'' is a distinct genus.
−
[[Image:Human-brachiosaurus size comparison.png|250px|thumb|left|Size comparison between ''Brachiosaurus'' and a human]]
 
−
Based on a complete composite skeleton, ''Brachiosaurus'' attained 25 meters (82 feet) in length and was probably able to raise its head about 13 meters (42 feet) 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 centimeters in length, as well as the  brachiosaurid scapulocoracoid referred to ''Ultrasauros''.
 
  
−
''Brachiosaurus'' has been estimated to have weighed anywhere between 15 metric tons (Russell et al. 1980) and 78 tons (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 tons (Paul 1988) to 37 tons (Christtiansen 1997). The 15% longer specimens hinted at above would have massed 48 to 56 tonnes.
+
===Size===
  
 +
For many decades, the brachiosaurs were the largest dinosaurs known. It has since been discovered that a number of giant titanosaurians (''Argentinosaurus'', for example) surpassed brachiosaurs in terms of sheer mass. More recently, another member of the same family, Brachiosauridae, but different genus, ''Sauroposeidon,'' has been discovered that seems likely to have outweighed the known brachiosaurs, albeit on incomplete fossil evidence.
  
−
==Discovery and species==
+
[[Image:Human-brachiosaurus size comparison.png|250px|thumb|left|Size comparison between ''Brachiosaurus'' and a human]]
−
The first ''Brachiosaurus'' was discovered in 1900 by Elmer S. Riggs, in the Grand River Canyon of western Colorado, in the United States.  
+
''Brachiosaurus'' is often considered to be the largest [[dinosaur]] known from a relatively complete [[fossil]]ized 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 ''Brachiosaurus brancai'', which some scientists now place in the [[genus]], ''Giraffatitan''.
  
−
[[Image:Brachiosaurus leg bone.jpg|right|thumb|250px|The front leg bone of a ''Brachiosaurus''.]]
+
The holotype material of the [[genus#type species|type species]], ''Brachiosaurus 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 meters (82 feet) in length and was probably able to raise its head about 13 meters (42 feet) above ground level.  Fragmentary material from larger specimens indicates that it could grow 15 percent longer than this. Such material includes an isolated fibula HMN XV2, 1340 centimeters in length, as well as the  brachiosaurid scapulocoracoid referred to ''Ultrasaurus.''
−
''Brachiosaurus'' includes three known species:
 
  
−
* ''B. altithorax'' [[Elmer Riggs|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.
+
''Brachiosaurus'' had been estimated to have weighed anywhere between 15 metric tons (Russell et al. 1980) and 78 tons (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 tons (Paul 1988) to 37 tons (Christiansen 1997). The 15 percent longer specimens hinted at above would have massed 48 to 56 tons.
−
* ''B. alataiensis'' [[Albert-Felix de Lapparent|de Lapparent]] & [[Zbyszewski]], 1957 has been referred to the new genus ''[[Lusotitan]]'' (Antunes and Mateus 2003). It is known from back bones ([[vertebra]]e), and parts of the [[hip]] and limbs, which were recovered in [[Estremadura]], [[Portugal]]. It lived about 150 [[million years ago]], during the [[Kimmeridgian]] [[faunal stage|age]] of the Late [[Jurassic]] [[geologic period|period]]. The type species is Lusotitan atalaiensis. Originally described as Brachiosaurus atalaiensis by Lapparent and Zybszewski in 1975, it was reclassified in 2003.
 
−
* ''?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.
 
  
−
Dixon, Dougal. 'The Complete Book of Dinosaurs.' Hermes House, 2006
+
===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.
  
−
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 [[cladistics|derived characteristic]]s of ''Brachiosaurus''. ''Giraffatitan'' has [[withers]] over its shoulder, and a rounded crest over its nostrils.
+
If ''Brachiosaurus'' was [[warm-blooded|endothermic]] (warm-blooded), it would have taken an estimated ten years to reach full size. If it were instead [[cold-blooded|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 [[gigantothermy|bulk endotherm]], it would have needed far less food to meet its daily energy needs. Scientists now believe that like most large dinosaurs, it was a gigantotherm. Gigantothermy refers to the phenomena were large, bulky ectothermic (cold-blooded, controlling temperature through external means) animals are more easily able to maintain a constant, relatively high body temperature than smaller animals by virtue of their greater volume to surface area ratio. A bigger animal has proportionately less of its body close to the outside environment than a smaller animal of otherwise similar shape, and so it gains heat from, or loses heat to, the environment much more slowly.
  
−
* ''Giraffatitan brancai'' [[Werner Janensch|Janensch]], 1914 (formerly ''B. brancai''): The new [[type species]], it is known from five partial skeletons, including at least three [[skull]]s 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.
+
===Environment and behavior===
 +
[[Image:Brachiosaurus Animatronic model NHM2.jpg|thumb|left|''Brachiosaurus'' at the ''Dino Jaws'' exhibition - Natural History Museum, London]].
 +
''Brachiosaurus'' was one of the largest dinosaurs of the [[Jurassic]] period; it appeared to have lived on prairies filled with [[fern]]s, [[bennettites]], and [[horsetail]]s, and it moved through vast [[conifer]] forests and groves of [[cycad]]s, seed ferns, and [[ginkgo]]s. 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.
  
−
==Description and environment==
+
''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 theorized 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, 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).
−
''Brachiosaurus'' was a [[sauropod]], one of a group of [[quadruped|four-legged]], [[herbivore|plant-eating]] dinosaurs with long [[neck]]s and [[tail]]s and relatively small [[brain]]s. Unlike other [[biological family|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 [[claw]]ed.
 
  
−
===Skull===
+
==Discovery and species==
−
''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]]''.
+
[[Image:Brachiosaurus leg bone.jpg|right|thumb|250px|The front leg bone of a ''Brachiosaurus''.]]
−
 
+
The first ''Brachiosaurus'' was discovered in 1900 by Elmer S. Riggs, in the Grand River Canyon of western [[Colorado]] in the [[United States]]. ''B. altithorax'' is the [[Genus#type species|type species]] and is known from two partial skeletons, the one recovered in Colorado and one recovered in Utah. It lived from 145 to 150 million years ago, during the Kimmeridgian to [[Tithonian]] [[geological time scale#Terminology|faunal stages]] of the late [[Jurassic]] period.
−
One complete ''Brachiosaurus'' skull is known. [[O.C. Marsh|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 ''[[Camarasaurus|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 {{Fact|date=April 2007}}.
 
  
−
If the ''Brachiosaurus'' was [[endothermy|endothermic]] (warm-blooded), it would have taken an estimated ten years to reach full size. If it were instead [[poikilothermy|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 [[gigantothermy|bulk endotherm]], it would have needed far less food to meet its daily energy needs. Scientists now believe that like most large dinosaurs, it was a [[gigantothermy|gigantotherm]].{{Fact|date=April 2007}}
+
The species ''B. alataiensis'' [[Albert-Felix de Lapparent|de Lapparent]] & [[Zbyszewski]], 1957, is known from back bones ([[vertebra]]e), and parts of the hip and limbs, which were recovered in Estremadura, [[Portugal]]. It lived about 150 million years ago, during the Kimmeridgian. However, recently ''B. alataiensis,'' which was originally described by Lapparent and Zybszewski in 1957, has been reclassified to a new [[genus]], ''Lusotitan'' and the type species is now known as ''Lusotitan atalaiensis''.  
  
−
===Environment and behaviour===
+
Another species, ''B. nougaredi'' de Lapparent, 1960, is known from a set of fused [[bone]]s 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. However, this may not be a distinct species.
−
[[Image:Brachiosaurus Animatronic model NHM2.jpg|thumb|left|''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 [[fern]]s, [[bennettites]] and [[horsetail]]s, and it moved through vast [[conifer]] forests and groves of [[cycad]]s, [[seed ferns]] and [[ginkgo]]s. 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'' [[nostril]]s, 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).
+
Historically, 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. Howevever, in 1991, George Olshevsky placed them in a new genus, ''Giraffatitan,'' because they do not share the [[cladistics|derived characteristic]]s of ''Brachiosaurus.'' ''Giraffatitan'' has withers over its shoulder and a rounded crest over its nostrils. The type species of ''Giraffatitan brancai'' [[Werner Janensch|Janensch]], 1914 (formerly ''B. brancai''), 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.
  
 
==Popular culture==
 
==Popular culture==
−
''Brachiosaurus'' is one of the most well-known dinosaurs amongst both paleontologists and the general public. As such, the genus has appeared in many films and television programmes, most notably ''[[Jurassic Park]]'', ''[[Jurassic Park 3]]'' and ''[[Walking with Dinosaurs]]''. It also appeared briefly at the end of ''[[Walking With Monsters]]''. A [[asteroid belt|main belt]] [[asteroid]], {{mp|1991 GX|7}}, has been named <!--no italics here—>9954 Brachiosaurus<!--no italics here—> in honor of the genus.<ref>{{cite web | title = JPL Small-Body Database Browser: 9954 Brachiosaurus (1991 GX7) | publisher = [[NASA]] | url= http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=9954 | accessdate = 2007-04-28}}</ref><ref name="Williams">{{cite web | author = Williams, Gareth | title = Minor Planet Names: Alphabetical List |publisher = [[Smithsonian Astrophysical Observatory]] | url= http://www.cfa.harvard.edu/iau/lists/MPNames.html | accessdate = 2007-02-10}}</ref>
+
''Brachiosaurus'' is one of the most well-known dinosaurs amongst both paleontologists and the general public. As such, the genus has appeared in many films and television programs, most notably ''Jurassic Park,'' ''Jurassic Park 3,'' and ''Walking with Dinosaurs.'' It also appeared briefly at the end of ''Walking With Monsters,'' A main belt [[asteroid]], {{mp|1991 GX|7}}, has been named <!--no italics here—>9954 Brachiosaurus<!--no italics here—> in honor of the genus (Williams 2007; JPL 2007).
−
 
 
−
''Brachiosaurus'' has also made an appearance in several computer games, including ''[[Jurassic Park:Operation Genesis]]'', ''[[Turok: Evolution]]'' and ''[[Jurassic Park: Rampage Edition]]'' for the [[SEGA]] consoles.
 
−
 
 
−
===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.
 
−
 
 
−
== Footnotes ==
 
−
{{reflist}}
 
  
 
==References==
 
==References==
  
−
nes<ref>[[Gregory S. Paul|Paul]], 1988</ref> to 37 tonnes (Christiansen 1997).
+
* Christiansen P. 1997. Locomotion in sauropod dinosaurs. ''Gaia'' 14: 45–75.
−
 
+
* Colbert, E. H. 1962. The weights of dinosaurs. ''American Museum Novitiates'' 2076: 1-16.
−
.<ref>[[Edwin Harris Colbert|Colbert]], 1962, table on p. 10. Exact figures given are 78.26 [[metric ton]]s / 85.63 [[short ton]]s.</ref>
+
* Dixon, D. 2006. ''The Complete Book of Dinosaurs: The Ultimate Reference to 355 Dinosaurs from the Triassic, Jurassic and Cretaceous periods, Including More than 900 Watercolors, Maps, Timelines and Photographs''. London: Hermes House. ISBN 0681375787
−
 
+
* Jet Propulsion Laboratory (JPL), California Institute of Technology. 2007. [http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=9954 JPL small-body database browser: 9954 Brachiosaurus (1991 GX7)]. ''NASA''. Retrieved April 28, 2007.
−
 
+
* Paul, G. S. 1988. The brachiosaur giants of the Morrison and Tendaguru with a description of a new subgenus, ''Giraffatitan'', and a comparison of the world's largest dinosaurs. ''Hunteria'' 2(3): 1-14.
−
 
+
* Russell, D. A., P. Beland, and J. S. McIntosh. 1980. Paleoecology of the dinosaurs of Tendaguru. ''Memoirs de Societe Geologique de France'' 139: 169-175.
−
* {{cite journal
+
* Williams, G. 2007. Minor planet names: Alphabetical list. ''Smithsonian Astrophysical Observatory''.
−
  | last = Colbert
 
−
  | first = E. H.
 
−
  | authorlink =
 
−
  | coauthors =
 
−
  | title = The Weights of Dinosaurs
 
−
  | journal = American Museum Novitiates
 
−
  | volume =
 
−
  | issue = 2076
 
−
  | pages = p. 1&ndash;16
 
−
  | publisher =
 
−
  | date = 1962
 
−
  | url =
 
−
  | doi =
 
−
  | id =
 
−
  | accessdate =  }}
 
−
* {{cite journal
 
−
  | last = Paul
 
−
  | first = G. S.  
 
−
  | authorlink =
 
−
  | coauthors =
 
−
  | title = The brachiosaur giants of the Morrison and Tendaguru with a description of a new subgenus, ''Giraffatitan'', and a comparison of the world's largest dinosaurs
 
−
  | journal = Hunteria
 
−
  | volume = 2
 
−
  | issue = 3
 
−
  | pages = 1&ndash;14
 
−
  | publisher =
 
−
  | date = 1988
 
−
  | url =
 
−
  | doi =
 
−
  | id =
 
−
  | accessdate =  }}
 
−
 
 
−
*[http://www.dinodata.org/index.php See entry on ''Brachiosaurus'' at DinoData] (registration required, free)
 
−
*[http://internt.nhm.ac.uk/jdsml/nature-online/dino-directory//detail.dsml?Genusqtype=starts+with&disp=gall&identifier=brach&sort=Genus&dataHeaderText_EX=dinosaurs+beginning+with+%27B%27&Genus=B&beginIndex=6&listPageURL=nameAZ%2edsml%3fGenusqtype%3dstarts%2bwith%26disp%3dgall%26sort%3dGenus%26Genus%3 dB ''Brachiosaurus'' (Natural History Museum)]
 
−
 
 
−
==External links==
 
−
*[http://www.fieldmuseum.org/museum_info/press/press_brachiosaurus.htm Expect awe-struck travelers], from the Field Museum. (O'Hare airport mount)
 
−
 
 
−
*[http://dinosaurier-web.de/galery/pages_b/brachiosaurus.html Dinosaurier-Web], Description and printable fact-sheet with picture (in German and English)
 
−
 
 
−
{{portalpar|Dinosaurs}}
 
  
−
{{credit|127492862}}
+
{{credit|Brachiosaurus|127492862|Gigantothermy|124331516|Brachiosauridae|119158804}}
 
[[Category:Life sciences]]
 
[[Category:Life sciences]]
 +
[[Category:Animals]]
 +
[[Category:Reptiles]]

Latest revision as of 02:00, 12 January 2023

Brachiosaurus
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
  • B. nougaredi

Brachiosaurus is an extinct genus of huge, sauropod dinosaurs that lived during the late Jurassic period. Sauropods comprise a suborder or infraorder of the saurischian ("lizard-hipped") dinosaurs, and in general were large, herbivorous dinosaurs. Brachiosaurus, which means "arm lizard," (from the Greek brachion/βραχιων meaning "arm" and sauros/σαυρος meaning "lizard") was so-named because the forelimbs were longer than the hind limbs. Brachiosaurus has become one of the most famous groups of all dinosaurs and is widely recognized worldwide.

Brachiosaurus represented one stage in the history of life. When the age of dinosaurs was over, it gave rise to a new stage that prepared the foundation for the modern earth, with the ascension of mammals and birds. For young earth creationists (YEC), the presence of dinosaurs such as Brachiosaurus represents a problem, for their appearance 150 millions years ago conflicts with the YEC's belief in an Earth only thousands of years old. But for most religious adherents, there is no conflict between their religious beliefs and an Earth billions of years old, which passed through various stages leading to the appearance of human beings.

Brachiosaurus, whose members are known as brachiosaurs, is a genus in the Brachiosauridae family, whose members are known as brachiosaurids. The brachiosaurs were among the largest animals ever to walk the earth.

Description and environment

Brachiosaurus was a sauropod (Sauropoda), a group of large, four-legged, plant-eating, dinosaurs with long necks, relatively small heads and brains, and generally long tails. Unlike other sauropods, Brachiosaurus 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 feet and the first three toes on its hind feet were clawed.

Brachiosaurus traditionally had been characterized 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. O. C. Marsh used it on his early reconstructions of Apatosaurus. 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.

Size

For many decades, the brachiosaurs were the largest dinosaurs known. It has since been discovered that a number of giant titanosaurians (Argentinosaurus, for example) surpassed brachiosaurs in terms of sheer mass. More recently, another member of the same family, Brachiosauridae, but different genus, Sauroposeidon, has been discovered that seems likely to have outweighed the known brachiosaurs, albeit on incomplete fossil evidence.

Size comparison between Brachiosaurus and a human

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 Brachiosaurus brancai, which some scientists now place in the genus, Giraffatitan.

The holotype material of the type species, Brachiosaurus 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 meters (82 feet) in length and was probably able to raise its head about 13 meters (42 feet) above ground level. Fragmentary material from larger specimens indicates that it could grow 15 percent longer than this. Such material includes an isolated fibula HMN XV2, 1340 centimeters in length, as well as the brachiosaurid scapulocoracoid referred to Ultrasaurus.

Brachiosaurus had been estimated to have weighed anywhere between 15 metric tons (Russell et al. 1980) and 78 tons (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 tons (Paul 1988) to 37 tons (Christiansen 1997). The 15 percent longer specimens hinted at above would have massed 48 to 56 tons.

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 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. Scientists now believe that like most large dinosaurs, it was a gigantotherm. Gigantothermy refers to the phenomena were large, bulky ectothermic (cold-blooded, controlling temperature through external means) animals are more easily able to maintain a constant, relatively high body temperature than smaller animals by virtue of their greater volume to surface area ratio. A bigger animal has proportionately less of its body close to the outside environment than a smaller animal of otherwise similar shape, and so it gains heat from, or loses heat to, the environment much more slowly.

Environment and behavior

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

.

Brachiosaurus was one of the largest dinosaurs of the Jurassic period; it appeared to have lived on prairies filled with ferns, bennettites, and horsetails, and it moved through vast conifer forests and 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 theorized 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, 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).

Discovery and species

The front leg bone of a Brachiosaurus.

The first Brachiosaurus was discovered in 1900 by Elmer S. Riggs, in the Grand River Canyon of western Colorado in the United States. B. altithorax is the type species and is known from two partial skeletons, the one recovered in Colorado and one recovered in Utah. It lived from 145 to 150 million years ago, during the Kimmeridgian to Tithonian faunal stages of the late Jurassic period.

The species B. alataiensis de Lapparent & Zbyszewski, 1957, 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. However, recently B. alataiensis, which was originally described by Lapparent and Zybszewski in 1957, has been reclassified to a new genus, Lusotitan and the type species is now known as Lusotitan atalaiensis.

Another species, B. nougaredi de Lapparent, 1960, is known from a 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. However, this may not be a distinct species.

Historically, 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. Howevever, 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. The type species of Giraffatitan brancai Janensch, 1914 (formerly B. brancai), 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.

Popular culture

Brachiosaurus is one of the most well-known dinosaurs amongst both paleontologists and the general public. As such, the genus has appeared in many films and television programs, most notably Jurassic Park, Jurassic Park 3, and Walking with Dinosaurs. It also appeared briefly at the end of Walking With Monsters, A main belt asteroid, 1991 GX7, has been named 9954 Brachiosaurus in honor of the genus (Williams 2007; JPL 2007).

References
ISBN links support NWE through referral fees

  • Christiansen P. 1997. Locomotion in sauropod dinosaurs. Gaia 14: 45–75.
  • Colbert, E. H. 1962. The weights of dinosaurs. American Museum Novitiates 2076: 1-16.
  • Dixon, D. 2006. The Complete Book of Dinosaurs: The Ultimate Reference to 355 Dinosaurs from the Triassic, Jurassic and Cretaceous periods, Including More than 900 Watercolors, Maps, Timelines and Photographs. London: Hermes House. ISBN 0681375787
  • Jet Propulsion Laboratory (JPL), California Institute of Technology. 2007. JPL small-body database browser: 9954 Brachiosaurus (1991 GX7). NASA. Retrieved April 28, 2007.
  • Paul, G. S. 1988. The brachiosaur giants of the Morrison and Tendaguru with a description of a new subgenus, Giraffatitan, and a comparison of the world's largest dinosaurs. Hunteria 2(3): 1-14.
  • Russell, D. A., P. Beland, and J. S. McIntosh. 1980. Paleoecology of the dinosaurs of Tendaguru. Memoirs de Societe Geologique de France 139: 169-175.
  • Williams, G. 2007. Minor planet names: Alphabetical list. Smithsonian Astrophysical Observatory.

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

The history of this article since it was imported to New World Encyclopedia:

Note: Some restrictions may apply to use of individual images which are separately licensed.

Retrieved from https://www.newworldencyclopedia.org/p/index.php?title=Brachiosaurus&oldid=1095090

Content is available under Creative Commons Attribution/Share-Alike License; additional terms may apply. See Terms of Use for details.
Copyright Logo
Powered by MediaWiki