Diplodocus
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{{for|the extinct amphibian|Diplocaulus}}
{{for|the Philadelphia-based producer and DJ|Diplo}}
{{Taxobox
| name = ''Diplodocus''
| fossil_range = [[Late Jurassic]]
| image = Diplodocus carnegi P1060066.jpg
| image_width = 250px
| image_caption = ''Diplodocus carnegiei'' skeleton, Naturkundemuseum, [[Berlin]].
| regnum = [[Animal]]ia
| phylum = [[Chordate|Chordata]]
| classis = [[Reptile|Sauropsida]]
| superordo = [[Dinosaur]]ia
| ordo = [[Saurischia]]
| subordo = [[Sauropodomorpha]]
| infraordo = [[Sauropoda]]
| familia = [[Diplodocidae]]
| genus = '''''Diplodocus'''''
| genus_authority = [[Othniel Charles Marsh|Marsh]], 1878
| subdivision_ranks = [[Species]]
| subdivision =
* ''D. longus'' <small>Marsh, 1878 ([[Type species|type]])</small>
* ''D. carnegiei'' <small>[[John Bell Hatcher|Hatcher]], 1901</small>
* ''D. hayi'' <small>Holland, 1924</small>
* ''D. hallorum'' <small>(Gillette, 1991) Lucas ''et al''., 2004</small>
| synonyms =
* ''Seismosaurus'' <small>Gillette, 1991</small>
}}
'''''Diplodocus''''' ({{pronEng|dɪˈplɒdəkəs}},<ref name="oed">{{cite book |author=Simpson, John; Edmund Weiner (eds.) |year=1989 |title=[[The Oxford English Dictionary]] |edition=2nd edition |location=Oxford |publisher=Oxford University Press |isbn=0-19-861186-2}}</ref><ref name="ahd">{{cite book |author=Pickett, Joseph P. et al. (eds.) |year=2000 |title=[[The American Heritage Dictionary of the English Language]] |edition=4th edition |location=Boston |publisher=Houghton Mifflin Company |isbn=0-395-82517-2}}</ref>
{{IPA|/daɪˈplɒdəkəs/}},<ref name="ahd"/> or {{IPA|/ˌdɪploʊˈdoʊkəs/}}<ref name="oed"/>)
is a [[genus]] of [[diplodocid]] [[sauropod]] [[dinosaur]] whose [[fossil]]s were first discovered in 1877 by [[Samuel Wendell Williston|S. W. Williston]]. The generic name, coined by [[Othniel Charles Marsh]] in 1878, is a [[Neo-Latin]] term derived from [[Ancient Greek|Greek]] {{unicode|διπλόος}} (''diploos'') "double" and {{unicode|δοκός}} (dokos) "beam",<ref name="oed"/> in reference to its double-beamed [[chevron (anatomy)|chevron bones]] located in the underside of the tail. These bones were initially believed to be unique to ''Diplodocus''; however, they have since then been discovered in other members of the [[diplodocid]] family and in non-diplodocid sauropods such as ''[[Mamenchisaurus]]''.
It lived in what is now western North America at the end of the [[Jurassic]] [[Period (geology)|Period]]. ''Diplodocus'' is one of the more common dinosaur fossils found in the Upper [[Morrison Formation]], a sequence of shallow marine and alluvial sediments deposited about 150 to 147 [[mega-annum|million years ago]], in what is now termed the [[Kimmeridgian]] and [[Tithonian]] [[faunal stage|stages]]. The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs such as ''[[Camarasaurus]]'', ''[[Barosaurus]]'', ''[[Apatosaurus]]'' and ''[[Brachiosaurus]]''.<ref> Christine C.E. & Peterson, F. (2004). "Reconstruction of the Upper Jurassic Morrison Formation extinct ecosystem—a synthesis". Sedimentary Geology '''167''', 309–355</ref>
''Diplodocus'' is among the most easily identifiable dinosaurs, with its classic dinosaur shape, long neck and tail and four sturdy legs. For many years, it was the longest dinosaur known. Its great size may have been a deterrent to the predators ''[[Allosaurus]]'' and ''[[Ceratosaurus]]'': their remains have been found in the same [[stratum|strata]], which suggests they coexisted with ''Diplodocus''.
==Description==
[[Image:Diplodocus size comparison.png|thumb|left|320px|Skeletal diagram, with humans for scale]]
One of the best-known sauropods, ''Diplodocus'' was a very large long-necked [[quadruped]]al animal, with a long, whip-like tail. Its forelimbs were slightly shorter than its hind limbs, resulting in a largely horizontal posture. The long-necked, long-tailed animal with four sturdy legs has been mechanically compared with a suspension bridge.<ref name="UDB">Lambert D. (1993)''The Ultimate Dinosaur Book'' ISBN 0-86438-417-3</ref> In fact, ''Diplodocus'' is the longest dinosaur known from a complete skeleton.<ref name="UDB">Lambert D. (1993)''The Ultimate Dinosaur Book'' ISBN 0-86438-417-3</ref> The partial remains of ''D. hallorum'' have increased the estimated length, though not as much as previously thought; when first described in 1991, discoverer David Gillete calculated it may have been up to 54 m (177.05 ft) long, making it the longest known dinosaur (excluding those known from especially poor remains, such as ''[[Amphicoelias]]''). Some weight estimates ranged as high as 113 (rather only 50) [[tonne]]s (125 US [[short tons]]). This review was based on recent findings that show that the giant tail vertebrae were actually placed further forward on the tail than Gillete originally calculated. The study shows that the complete ''Diplodocus'' skeleton at the [[Carnegie Museum of Natural History]] in [[Pittsburgh, Pennsylvania]] on which estimates of ''Seismosaurus'' were based had its 13th tail vertebra come from another dinosaur, throwing size estimates for ''Seismosaurus'' off by up to 30%. While dinosaurs such as ''[[Supersaurus]]'' were probably longer, fossil remains of these animals are only fragmentary.<ref>Wedel, M.J. and Cifelli, R.L. ''Sauroposeidon'': Oklahoma's Native Giant. 2005. Oklahoma Geology Notes 65:2.</ref>
[[Image:Fig023.jpg|thumb|''Diplodocus'' skull from [[Bone-Cabin Quarry]].]]
The skull of ''Diplodocus'' was very small, compared with the [[largest organism|size]] of the animal, which could reach up to {{convert|35|m|ft|0|abbr=on|link=on}},<ref name ="dinosauria04b"/> of which over {{convert|6|m|ft|0|abbr=on}} was neck.<ref name ="dinosauria04a">{{cite book|title=The Dinosauria (2nd Edition)|year=2004|chapter=Sauropoda|editor=Weishampel DB, Dodson P, Osmólska H|author=Upchurch P, Barrett PM, Dodson P|pages=316|publisher=University of California Press|id=ISBN 0-520-24209-2}}</ref> ''Diplodocus'' had small, 'peg'-like teeth that pointed forward and were only present in the [[Anatomical terms of location#Anterior and posterior|anterior]] sections of the jaws.<ref>Upchurch, P. & Barrett, P.M. (2000). Chapter 4: The evolution of sauropod feeding mechanism. IN: ''Evolution of Herbivory in Terrestrial Vertebrates'' ISBN 0-521-59449-9</ref> Its braincase was small. The neck was composed of at least fifteen [[vertebra]]e and is now believed to have been generally held parallel to the ground and unable to have been elevated much past horizontal.<ref> Stevens, K.A. & Parrish, M. (1999). "Neck Posture and Feeding Habits of Two Jurassic Sauropod Dinosaurs". Science '''284''', 798–800</ref> Modern mass estimates have tended to be in the 10 to 16 [[tonne]] (11–17.6 [[ton]]) range: 10 tonnes (11 tons);<ref name=DBBM80>Dodson, P., Behrensmeyer, A.K., Bakker, R.T., and McIntosh, J.S. (1980). Taphonomy and paleoecology of the dinosaur beds of the Jurassic Morrison Formation. ''Paleobiology'' '''6''':208–232.</ref> 11.5 tonnes (12.7 tons);<ref name=GSP94>Paul, G.S. (1994). Big sauropods - really, really big sauropods. ''The Dinosaur Report, The Dinosaur Society'' Fall:12–13.</ref> 12.7 tonnes (14 tons);<ref name=JRF03>Foster, J.R. (2003). Paleoecological Analysis of the Vertebrate Fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain Region, U.S.A. New Mexico Museum of Natural History and Science:Albuquerque, New Mexico. Bulletin 23.</ref> and 16 tonnes (17.6 tons).<ref name=CDFJR87>Coe, M.J., Dilcher, D.L., Farlow, J.O., Jarzen, D.M., and Russell, D.A. (1987). Dinosaurs and land plants. In: Friis, E.M., Chaloner, W.G., and Crane, P.R. (eds.). ''The Origins of Angiosperms and Their Biological Consequences.'' Cambridge University Press:New York, 225–258. ISBN 0521323576.</ref>
[[Image:Diplodocus caudal vertebrae NHM.JPG|thumb|left|Caudal vertebrae of ''Diplodocus carnegiei'', [[Natural History Museum]], [[London]].]]
''Diplodocus'' had an extremely long tail, composed of about 80 [[caudal]] vertebrae,<ref name ="Rogers05">{{cite book|title=The Sauropods:Evolution and Paleobiology|year=2005|chapter=Overview of Sauropod Phylogeny and Evolution|editor=Rogers KA & Wilson JA(eds)|author=Wilson JA|page=15–49|publisher=Indiana University Press|id=ISBN 0-520-24623-3}}</ref> which is almost double the number some of the earlier sauropods had in their tails (such as ''[[Shunosaurus]]'' with 43), and far more than contemporaneous [[macronaria]]ns had (such as ''[[Camarasaurus]]'' with 53). There has been speculation as to whether it may have had a defensive<ref>
{{cite journal|author= Holland WJ|year=1915|title=Heads and Tails: a few notes relating to the structure of sauropod dinosaurs.|journal=Annals of the Carnegie Museum|volume=9|pages=273–278}}</ref> or noisemaking function.<ref> {{cite journal|author= Myhrvold NP and Currie PJ|year=1997|title=Supersonic sauropods? Tail dynamics in the diplodocids|journal=Paleobiology|volume=23|pages=393–409}}</ref> The tail may have served as a counterbalance for the neck. The middle part of the tail had 'double beams' (oddly-shaped bones on the underside, which gave ''Diplodocus'' its name). They may have provided support for the vertebrae, or perhaps prevented the blood vessels from being crushed if the animal's heavy tail pressed against the ground. These 'double beams' are also seen in some related dinosaurs.
Like other sauropods, the manus (front "feet") of ''Diplodocus'' were highly modified, with the finger and hand bones arranged into a vertical column, [[horseshoe]]-shaped in cross section. ''Diplodocus'' lacked claws on all but one digit of the front limb, and this claw was unusually large relative to other sauropods, flattened from side to side, and detached from the bones of the hand. The function of this unusually specialized claw is unknown.<ref name="bonnan2003">Bonnan, M. F. (2003). "The evolution of manus shape in sauropod dinosaurs: implications for functional morphology, forelimb orientation, and phylogeny." ''Journal of Vertebrate Paleontology'', '''23''': 595-613.</ref>
==Discovery and species==
[[Image:Large holland diplodocus.jpg|thumb|Presentation of the first replica of ''Diplodocus carnegiei'' to the trustees of the [[British Museum of Natural History]], [[12 May]], 1905. [[Lord Avebury]] speaking.]]
Several species of ''Diplodocus'' were described between 1878 and 1924. The first [[skeleton]] was found at [[Como Bluff]], [[Wyoming]] by [[Benjamin Franklin Mudge|Benjamin Mudge]] and [[Samuel Wendell Williston]] in 1878, and was named ''Diplodocus longus'' ('long double-beam'), by [[paleontology|paleontologist]] [[Othniel Charles Marsh]] in 1878.<ref>Marsh OC. Principal characters of American Jurassic dinosaurs. Part I. American Journal of Science 3; 411–416 (1878).</ref> ''Diplodocus'' remains have since been found in the [[Morrison Formation]] of the western [[United States|U.S.]] States of [[Colorado]], [[Utah]], [[Montana]] and [[Wyoming]]. [[Fossil]]s of this animal are common, except for the [[skull]], which is often missing from otherwise complete skeletons. Although not the type species, ''D. carnegiei'' is the most completely known and most famous due to the large number of casts of its skeleton in museums around the world.
The two Morrison Formation sauropod genera ''Diplodocus'' and ''Barosaurus'' had very similar limb bones. In the past, many isolated limb bones were automatically attributed to ''Diplodocus'' but may, in fact, have belonged to ''Barosaurus''.<ref>{{cite book|author=McIntosh|year=2005|chapter=The Genus Barosaurus ([[Othniel Charles Marsh|Marsh]])|editor=Carpenter, Kenneth and Tidswell, Virginia (ed.)|title=Thunder Lizards: The Sauropodomorph Dinosaurs|pages=38–77|publisher= Indiana University Press|id=ISBN 0-253-34542-1}}</ref>
===Valid species===
''Seismosaurus redirects here. For the fictional mecha based on this dinosaur, see [[Seismosaurus (Zoids)]]''
* '''''D. longus''''', the [[type species]], is known from two skulls and a caudal series from the Morrison Formation of Colorado and Utah.<ref name ="dinosauria04b">{{cite book|title=The Dinosauria (2nd Edition)|year=2004|chapter=Sauropoda|editor=Weishampel DB, Dodson P, Osmólska H|author=Upchurch P, Barrett PM, Dodson P|pages=305|publisher=University of California Press|id=ISBN 0-520-24209-2}}</ref>
* '''''D. carnegiei''''', named after [[Andrew Carnegie]], is the best known, mainly due to a near-complete skeleton collected by Jacob Wortman, of the [[Carnegie Museums of Pittsburgh#Carnegie Museum of Natural History|Carnegie Museum of Natural History]] in [[Pittsburgh, Pennsylvania]] and described and named by [[John Bell Hatcher]] in 1901.
* '''''D. hayi''''', known from a partial skeleton discovered by William H. Utterback in 1902 near [[Sheridan, Wyoming]], was described in 1924.<ref>Holland WJ. The skull of ''Diplodocus''. Memoirs of the Carnegie Museum IX; 379–403 (1924).</ref>
[[Image:SeismosaurusDB.jpg|thumb|''Diplodocus hallorum'' (formerly known as ''Seismosaurus'')]]
* '''''D. hallorum''''', first described in 1991 by Gillette as ''Seismosaurus halli'' from a partial skeleton comprising vertebrae, pelvis and ribs. Olshevsky later attempted to emend the name as ''S. hallorum'', citing incorrect grammar on the part of the original authors, a recommendation that has been followed by others including Carpenter (2006). In 2004, a presentation at the annual conference of the [[Geological Society of America]] made a case for ''Seismosaurus'' being a [[junior synonym]] of ''Diplodocus''.<ref>Lucas S, Herne M, Heckert A, Hunt A, and Sullivan R. [http://gsa.confex.com/gsa/2004AM/finalprogram/abstract_77727.htm Reappraisal of ''Seismosaurus'', A Late Jurassic Sauropod Dinosaur from New Mexico.] The Geological Society of America, 2004 Denver Annual Meeting (November 7–10, 2004). Retrieved on [[2007-05-24]].</ref> This was followed by a much more detailed publication in 2006, which not only renamed the species ''Diplodocus hallorum'', but also speculated that it could prove to be the same as ''D. longus''.<ref>{{cite book|title=Paleontology and Geology of the Upper Morrison Formation|year=2006|chapter=Taxonomic status of ''Seismosaurus hallorum'', a Late Jurassic sauropod dinosaur from New Mexico|editor=Foster, J.R., and Lucas, S.G.|author=Lucas, S.G., Spielman, J.A., Rinehart, L.A., Heckert, A.B., Herne, M.C., Hunt, A.P., Foster, J.R., and Sullivan, R.M.|pages=149–161|publisher=New Mexico Museum of Natural History and Science (bulletin 36)|id=ISSN 1524-4156}}</ref> The position that ''D. hallorum'' should be regarded as a specimen of ''D. longus'' was also taken by the authors of a redescription of ''[[Supersaurus]]'', refuting a previous hypothesis that ''Seismosaurus'' and ''Supersaurus'' were the same.<ref name=LHW07>{{cite journal |last=Lovelace |first=David M. |coauthors=Hartman, Scott A.; and Wahl, William R. |year=2007 |title=Morphology of a specimen of ''Supersaurus'' (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny |journal=Arquivos do Museu Nacional |volume=65 |issue=4 |pages=527–544 }}</ref>
===''Nomina dubia'' (doubtful species)===
* ''D. lacustris'' is a ''[[nomen dubium]]'', named by Marsh in 1884, from remains of a smaller animal from [[Morrison, Colorado]].<ref name="marsh84"/> These remains are now believed to have been from an immature animal, rather than from a separate species.<ref name="upchurchetal2004">Upchurch, P., Barrett, P.M., and Dodson, P. (2004). "Sauropoda." In D. B. Weishampel, P. Dodson, and H. Osmólska (eds.), ''The Dinosauria (2nd edition)''. University of California Press, Berkeley 259–322.</ref>
==Paleobiology==
Due to a wealth of skeletal remains, ''Diplodocus'' is one of the best-studied dinosaurs. Many aspects of its lifestyle have been subjects of various theories over the years.
===Habitat===
[[Image:DiplodocusDB.jpg|left|thumb|Illustration of two ''Diplodocus longus'']]
Marsh and then [[John Bell Hatcher|Hatcher]]<ref>Hatcher JB. "''Diplodocus'' (Marsh): Its osteology, taxonomy, and probable habits, with a restoration of the skeleton,". Memoirs of the Carnegie Museum, vol. 1 (1901), pp. 1–63</ref> assumed the animal was aquatic, because of the position of its nasal openings at the apex of the cranium. Similar aquatic behavior was commonly depicted for other large sauropods such as ''[[Brachiosaurus]]'' and ''[[Apatosaurus]]''. The idea of an aquatic existence was later debunked, as the water pressure on the chest wall of ''Diplodocus'' was proven to have been too great for the animal to have breathed. Since the 1970s, general consensus has the sauropods as firmly terrestrial animals, browsing on trees. However, a more recent theory suggests a likely [[riparian]] habitat for ''Diplodocus''.
===Posture===
[[Image:Diplodocus by Hay 1910.jpg|thumb|right|An outmoded depiction of ''Diplodocus'' by Oliver P. Hay (1910), with a high head and sprawled limbs<ref> Hay, O. P., 1910, Proceedings of the
Washington Academy of Sciences, vol. 12,, pp. 1–25</ref>]]
The depiction of ''Diplodocus'' posture has changed considerably over the years. For instance, a classic 1910 reconstruction by Oliver P. Hay depicts two ''Diplodocus'' with splayed lizard-like limbs on the banks of a river. Hay argued that ''Diplodocus'' had a sprawling, lizard-like gait with widely-splayed legs,<ref>Hay, Dr. Oliver P., "On the Habits and Pose of the Sauropod Dinosaurs, especially of Diplodocus." The American Naturalist, Vol. XLII, Oct. 1908</ref> and was supported by Gustav Tornier. However, this hypothesis was put to rest by W. J. Holland, who demonstrated that a sprawling ''Diplodocus'' would have needed a trench to pull its belly through.<ref>Holland, Dr. W. J., "A Review of Some Recent Criticisms of the Restorations of Sauropod Dinosaurs Existing in the Museums of the United States, with Special Reference to that of Diplodocus carnegiei in the Carnegie Museum", The American Naturalist, 44:259–283. 1910.</ref>
[[Image:Diplodocus Woodward 1905.jpg|thumb|left|A classic depiction of ''Diplodocus'' by Mary Woodward (1905), with neck high up in the air and tail on the ground, a posture now believed to be incorrect]]
Later, [[diplodocidae|diplodocids]] were often portrayed with their necks held high up in the air, allowing them to graze from tall trees. More recently, scientists have argued that the heart would have had trouble sustaining sufficient blood pressure to oxygenate the brain. Furthermore, more recent studies have shown that the structure of the neck vertebrae would not have permitted the neck to bend far upwards.<ref name="stevens05">{{cite book|author=Stevens KA, Parrish JM|year=2005|chapter=Neck Posture, Dentition and Feeding Strategies in Jurassic Sauropod Dinosaurs|editor=Carpenter, Kenneth and Tidswell, Virginia (ed.)|title=Thunder Lizards: The Sauropodomorph Dinosaurs|pages=212–232|publisher= Indiana University Press|id=ISBN 0-253-34542-1}}</ref><ref name="Upchurch2000">{{cite web|last=Upchurch |first=P, ''et al.''|title="Neck Posture of Sauropod Dinosaurs"|publisher=''Science'' 287, 547b (2000); DOI: 10.1126/science.287.5453.547b |date=2000|url=http://www.sciencemag.org/cgi/reprint/287/5453/547b.pdf|format = PDF | accessdate =2006-11-28 }}</ref>
As with the related genus ''Barosaurus'', the very long neck of ''Diplodocus'' is the source of much controversy among scientists. A 1992 [[Columbia University]] study of Diplodocid neck structure indicated that the longest necks would have required a 1.6 ton heart — a tenth of the animal's body weight. The study proposed that animals like these would have had rudimentary auxiliary 'hearts' in their necks, whose only purpose was to pump blood up to the next 'heart'.<ref name="UDB">Lambert D. (1993)''The Ultimate Dinosaur Book'' ISBN 0-86438-417-3</ref>
While the long neck has traditionally been interpreted as a feeding adaptation, a recent study<ref>Senter, P. "Necks for Sex: Sexual Selection as an Explanation for Sauropod Neck Elongation". Journal of Zoology, 2006</ref> suggests that the oversized neck of ''Diplodocus'' and its relatives may have been primarily a sexual display, with any other feeding benefits coming second.
===Diet===
''Diplodocus'' has highly unusual teeth compared to other sauropods. The crowns are long and slender, elliptical in cross-section, while the apex forms a blunt triangular point.<ref name="Upchurch"> Upchurch, P. & Barrett, P.M. (2000). Chapter 4: The evolution of sauropod feeding mechanism. IN: ''Evolution of Herbivory in Terrestrial Vertebrates'' ISBN 0-521-59449-9</ref> The most prominent wear facet is on the apex, though unlike all other wear patterns observed within sauropods, ''Diplodocus'' wear patterns are on the labial (cheek) side of both the upper and lower teeth.<ref name="Upchurch"> Upchurch, P. & Barrett, P.M. (2000). Chapter 4: The evolution of sauropod feeding mechanism. IN: ''Evolution of Herbivory in Terrestrial Vertebrates'' ISBN 0-521-59449-9</ref> What this means is ''Diplodocus'' and other diplodocids had a radically different feeding mechanism than other sauropods. Unilateral branch-stripping is the most likely feeding behavior of ''Diplodocus'',<ref>Norman, D.B. (1985). "The illustrated Encyclopedia of Dinosaurs". London: Salamander Books Ltd</ref><ref>Dodson, P. (1990). Sauropod paleoecology. IN: "The Dinosauria" 1st Edition, (Eds. Weishampel, D.B., Dodson, P. & Osmólska, H.)</ref><ref>Barrett, P.M. & Upchurch, P. (1994). Feeding mechanisms of ''Diplodocus''. Gaia '''10''', 195–204</ref> as it explains the unusual wear patterns of the teeth (coming from tooth-food contact). In unilateral branch stripping, one tooth row would have been used to strip foliage from the stem, while the other would act as a guide and stabilizer. With the elongated preorbital (in-front of the eyes) region of the skull, longer portions of stems could be stripped in a single action.<ref name="Upchurch"> Upchurch, P. & Barrett, P.M. (2000). Chapter 4: The evolution of sauropod feeding mechanism. IN: ''Evolution of Herbivory in Terrestrial Vertebrates'' ISBN 0-521-59449-9</ref> Also the palinal (backwards) motion of the lower jaws could have contributed two significant roles to feeding behaviour: 1) an increased gape, and 2) allowed fine adjustments of the relative positions of the tooth rows, creating a smooth stripping action.<ref name="Upchurch"> Upchurch, P. & Barrett, P.M. (2000). Chapter 4: The evolution of sauropod feeding mechanism. IN: ''Evolution of Herbivory in Terrestrial Vertebrates'' ISBN 0-521-59449-9</ref>
With a laterally and dorsoventrally flexible neck, and the possibility of using its tail and rearing up on its hind limbs (tripodal ability), ''Diplodocus'' would have had the ability to browse at many levels (low, medium, and high), up to approximately 10 metres (33 ft) from the ground.<ref>Barrett, P.M. & Upchurch, P. (2005). Sauropodomorph Diversity through Time, Paleoecological and Macroevolutionary Implications. IN: "The Sauropods: Evolution and Paleobiology" (Eds. Curry, K. C.)</ref> The neck's range of movement would have also allowed the head to graze below the level of the body, leading some scientists to speculate on whether ''Diplodocus'' grazed on submerged water plants, from riverbanks. This concept of the feeding posture is supported by the relative lengths of front and hind limbs. Furthermore, its peglike teeth may have been used for eating soft water plants.<ref name="stevens05">{{cite book|author=Stevens KA, Parrish JM|year=2005|chapter=Neck Posture, Dentition and Feeding Strategies in Jurassic Sauropod Dinosaurs|editor=Carpenter, Kenneth and Tidswell, Virginia (ed.)|title=Thunder Lizards: The Sauropodomorph Dinosaurs|pages=212–232|publisher= Indiana University Press|id=ISBN 0-253-34542-1}}</ref>
===Other anatomical aspects===
[[Image:diploheads.jpg|thumb|right|a) skull, b) classic rendering of the head with nostrils on top, c) Bakker's theory of a trunk, d) modern depiction with nostrils low on the snout and a possible resonating chamber]]
The head of ''Diplodocus'' has been widely depicted with the nostrils on top due to the position of the nasal openings at the apex of the skull. There has been speculation over whether such a configuration meant that ''Diplodocus'' may have had a trunk.<ref>Bakker, Robert T. (1986) The Dinosaur Heresies: New Theories Unlocking the Mystery of the Dinosaurs and their Extinction. New York: Morrow.</ref> A recent study<ref>Knoll, F., Galton, P.M., López-Antoñanzas, R. (2006). "Paleoneurological evidence against a proboscis in the sauropod dinosaur ''Diplodocus''." ''Geobios'', '''39''': 215–221</ref> surmised there was no paleoneuroanatomical evidence for a trunk. It noted that the [[facial nerve]] in an animal with a trunk, such as an elephant, is large as it innervates the trunk. The evidence suggests that the facial nerve is very small in ''Diplodocus''. Studies by Lawrence Witmer (2001) indicated that, while the nasal openings were high on the head, the actual, fleshy nostrils were situated much lower down on the snout.<ref>Lawrence M. Witmer et al., "Nostril Position in Dinosaurs and other Vertebrates and its Significance for Nasal Function." Science '''293''', 850 (2001)</ref>
Recent discoveries have suggested that ''Diplodocus'' and other diplodocids may have had narrow, pointed [[keratin]]ous spines lining their back, much like those on an [[iguana]].<ref>Czerkas, S. A. (1993). "Discovery of dermal spines reveals a new look for sauropod dinosaurs." Geology '''20''', 1068–1070</ref><ref>Czerkas, S. A. (1994). "The history and interpretation of sauropod skin impressions." In ''Aspects of Sauropod Paleobiology'' (M. G. Lockley, V. F. dos Santos, C. A. Meyer, and A. P. Hunt, Eds.), ''Gaia'' '''No. 10'''. (Lisbon, Portugal).</ref> This radically different look has been incorporated into recent reconstructions, notably ''[[Walking with Dinosaurs]]''. It is unknown exactly how many diplodocids had this trait, and whether it was present in other sauropods.
===Reproduction and growth===
While there is no evidence for ''Diplodocus'' nesting habits, other [[sauropod]]s such as the [[titanosaur]]ian ''[[Saltasaurus]]'' have been associated with nesting sites.<ref>Walking on Eggs: The Astonishing Discovery of Thousands of Dinosaur Eggs in the Badlands of Patagonia, by Luis Chiappe and Lowell Dingus. [[June 19]], [[2001]], Scribner</ref><ref>Grellet-Tinner, Chiappe, & Coria, "Eggs of titanosaurid sauropods from the Upper Cretaceous of Auca Mahuevo (Argentina)", Can. J. Earth Sci. 41(8): 949–960 (2004)</ref> The titanosaurian nesting sites indicate that may have laid their eggs communally over a large area in many shallow pits, each covered with vegetation. It is possible that ''Diplodocus'' may have done the same. The documentary ''[[Walking with Dinosaurs]]'' portrayed a mother ''Diplodocus'' using an [[ovipositor]] to lay eggs, but it was pure speculation on the part of the documentary.
Following a number of [[bone]] [[histology]] studies, ''Diplodocus'', along with other sauropods, grew at a very fast rate, reaching [[sexual maturity]] at just over a decade, though continuing to grow throughout their lives.<ref> Sander, P. M. (2000). "Long bone histology of the Tendaguru sauropods: Implications for growth and biology". Paleobiology '''26''', 466–488</ref><ref>Sander, P. M., N. Klein, E. Buffetaut, G. Cuny, V. Suteethorn, and J. Le Loeuff (2004). "Adaptive radiation in sauropod dinosaurs: Bone histology indicates rapid evolution of giant body size through acceleration". Organisms, Diversity & Evolution '''4''', 165–173 </ref><ref> Sander, P. M., and N. Klein (2005). "Developmental plasticity in the life history of a prosauropod dinosaur". Science '''310''' 1800–1802</ref> Previous thinking held that sauropods would keep growing slowly throughout their lifetime, taking decades to reach maturity.
==Classification==
[[Image:Diplodocus NHM.JPG|thumb|left|Mounted replica ''Diplodocus carnegiei'' skeleton, [[Natural History Museum]], [[London]].]]
''Diplodocus'' is both the [[type genus]] of, and gives its name to '''[[Diplodocidae]]''', the family to which it belongs.<ref name="marsh84">Marsh, O.C. 1884. Principal characters of American Jurassic dinosaurs. Part VII. On the Diplodocidae, a new family of the Sauropoda. ''American Journal of Science'' 3: 160–168.</ref> Members of this family, while still massive, are of a markedly more slender build when compared with other sauropods, such as the [[titanosaur]]s and [[brachiosaur]]s. All are characterised by long necks and tails and a horizontal posture, with forelimbs shorter than hindlimbs. Diplodocids flourished in the Late Jurassic of North America and possibly Africa<ref name ="Rogers05">{{cite book|title=The Sauropods:Evolution and Paleobiology|year=2005|chapter=Overview of Sauropod Phylogeny and Evolution|editor=Rogers KA & Wilson JA(eds)|author=Wilson JA|page=15–49|publisher=Indiana University Press|id=ISBN 0-520-24623-3}}</ref> and appear to have been replaced ecologically by titanosaurs during the [[Cretaceous]].
A subfamily, '''Diplodocinae''', was erected to include ''Diplodocus'' and its closest relatives, including ''[[Barosaurus]]''. More distantly related is the contemporaneous ''[[Apatosaurus]]'', which is still considered a diplodocid although not a diplodocine, as it is a member of the subfamily Apatosaurinae.<ref name="taylornaish05">Taylor, M.P. & Naish, D. 2005. The phylogenetic taxonomy of Diplodocoidea (Dinosauria: Sauropoda). ''PaleoBios'' 25(2): 1–7. (download [http://www.miketaylor.org.uk/dino/pubs/ here])</ref><ref name="harris06">Harris, J.D. 2006. The significance of ''Suuwassea emiliae'' (Dinosauria: Sauropoda) for flagellicaudatan intrarelationships and evolution. ''Journal of Systematic Palaeontology'' 4(2): 185–198.</ref> The [[Portugal|Portuguese]] ''[[Dinheirosaurus]]'' and the African ''[[Tornieria]]'' have also been identified as close relatives of ''Diplodocus'' by some authors.<ref name="bonapartematerus99">Bonaparte, J.F. & Mateus, O. 1999. A new diplodocid, ''Dinheirosaurus lourinhanensis'' gen. et sp. nov., from the Late Jurassic beds of Portugal. ''Revista del Museo Argentino de Ciencias Naturales''. 5(2):13–29. (download [http://www.lusodinos.dinodata.org/index.php?option=com_content&task=category§ionid=8&id=20&Itemid=29 here])</ref><ref name="rauhutetal05">Rauhut, O.W.M., Remes, K., Fechner, R., Cladera, G., & Puerta, P. 2005. Discovery of a short-necked sauropod dinosaur from the Late Jurassic period of Patagonia. ''Nature'' 435: 670–672.</ref>
The '''Diplodocoidea''' comprises the diplodocids, as well as [[dicraeosaurid]]s, [[rebbachisaurid]]s, ''[[Suuwassea]]'',<ref name="taylornaish05">Taylor, M.P. & Naish, D. 2005. The phylogenetic taxonomy of Diplodocoidea (Dinosauria: Sauropoda). ''PaleoBios'' 25(2): 1–7. (download [http://www.miketaylor.org.uk/dino/pubs/ here])</ref><ref name="harris06">Harris, J.D. 2006. The significance of ''Suuwassea emiliae'' (Dinosauria: Sauropoda) for flagellicaudatan intrarelationships and evolution. ''Journal of Systematic Palaeontology'' 4(2): 185–198.</ref> ''[[Amphicoelias]]''<ref name="rauhutetal05">Rauhut, O.W.M., Remes, K., Fechner, R., Cladera, G., & Puerta, P. 2005. Discovery of a short-necked sauropod dinosaur from the Late Jurassic period of Patagonia. ''Nature'' 435: 670–672.</ref> and possibly ''[[Haplocanthosaurus]]'',<ref name="Wilson2002">Wilson, J. A., 2002, "Sauropod dinosaur phylogeny: critique and cladistica analysis". Zoological Journal of the Linnean Society 136: 217–276.</ref> and/or the [[nemegtosaurid]]s.<ref name ="dinosauria04a">{{cite book|title=The Dinosauria (2nd Edition)|year=2004|chapter=Sauropoda|editor=Weishampel DB, Dodson P, Osmólska H|author=Upchurch P, Barrett PM, Dodson P|pages=316|publisher=University of California Press|id=ISBN 0-520-24209-2}}</ref> This [[clade]] is the sister group to, ''Camarasaurus'', [[brachiosaurid]]s and titanosaurians; the Macronaria.<ref name ="dinosauria04a">{{cite book|title=The Dinosauria (2nd Edition)|year=2004|chapter=Sauropoda|editor=Weishampel DB, Dodson P, Osmólska H|author=Upchurch P, Barrett PM, Dodson P|pages=316|publisher=University of California Press|id=ISBN 0-520-24209-2}}</ref><ref name="Wilson2002">Wilson, J. A., 2002, "Sauropod dinosaur phylogeny: critique and cladistica analysis". Zoological Journal of the Linnean Society 136: 217–276.</ref> Together they comprise Neosauropoda; the largest, most diverse and successful group of [[sauropodomorph]] dinosaurs.
==In popular culture==
[[Image:Baltow,Poland Diplodocus+Allosaurus.jpg|thumb|Model ''Diplodocus'' standing on its hind legs in Bałtów, Poland.]]
''Diplodocus'' has been a famous and much-depicted dinosaur. Much of this has probably been due to its wealth of skeletal remains and former status as the longest known dinosaur. However, the donation of many mounted skeletal casts around the world a century ago<ref name=RTB86>{{cite book |last=Bakker |first=Robert T. |authorlink=Robert T. Bakker |title=The Dinosaur Heresies: New Theories Unlocking The Mystery of the Dinosaurs and Their Extinction |year=1986 |publisher=William Morrow |location=New York |isbn=0140100555 |pages=203}}</ref> did much to familarize it to people worldwide. Casts of ''Diplodocus'' skeletons are still displayed in many museums worldwide, including an unusual ''D. hayi'' in the [[Houston Museum of Natural Science]], and ''D. carnegiei'' in the [[Natural History Museum]] in [[London]], the Natural Science Museum in [[Madrid]], [[Spain]], the [[Senckenberg Museum]] in [[Frankfurt]], [[Germany]], the [[Field Museum of Natural History]] in [[Chicago]] and, of course, the original is still on display at the [[Carnegie Museums of Pittsburgh#Carnegie Museum of Natural History|Carnegie Museum of Natural History]] in Pittsburgh. A mounted skeleton of ''D. longus'' is at the Smithsonian [[National Museum of Natural History]] in [[Washington, D. C.]], while a mounted skeleton of ''D. hallorum'' (formerly ''Seismosaurus''), which may be the same as ''D. longus'', can be found at the [[New Mexico Museum of Natural History and Science]].
''Diplodocus'' has been a frequent subject in dinosaur films, both factual and fictional. It was featured in the second episode of the award-winning BBC television series ''[[Walking with Dinosaurs]]''. The episode "Time of the Titans" follows the life of a simulated ''Diplodocus'' 152 million years ago. The animated feature [[Fantasia (film)|''Fantasia'']] features many sauropods in the [[Rite of Spring]] sequence, some narrower-headed ones of which may be ''Diplodocus''. In literature, [[James A. Michener]]'s book ''[[Centennial (novel)|Centennial]]'' has a chapter devoted to ''Diplodocus'', narrating the life and death of one individual.
Diplodocus is a commonly-seen figure in dinosaur [[toy]] and [[scale model]] lines. It has had two separate figures in the [[Carnegie Collection]].
==References==
{{reflist|2}}
==External links==
{{commons|Diplodocus|Diplodocus}}
{{portalpar|Dinosaurs}}
* [http://www.nhm.ac.uk/jdsml/nature-online/dino-directory/detail.dsml?Genus=Diplodocus ''Diplodocus'' in the Dino Directory]
*[http://www.mncn.csic.es/home800.php Museo Nacional de Ciencias Naturales, Madrid]
*[http://www.antiquebooks.net/readpage.html Diplodocus Marsh, by J.B. Hatcher 1901] - Its Osteology, Taxonomy, and Probable Habits, with a Restoration of the Skeleton. Memoirs of the Carnegie Museum, Volume 1, Number 1, 1901. Full text, Free to read.
*[http://www.carnegiemnh.org/vp/history.html Carnegie Museum of Natural History - History]
*[http://skeletaldrawing.com/sauropods/sauropods.htm Skeletal restorations of diplodocids] including ''D. carnegii'', ''D. longus'', and ''D. hallorum'', from Scott Hartman's Skeletal Drawing website.
* [http://www.ageofdinosaur.com/ch05.htm Chapter 5: The Amphibious Dinosaurs - Brontosaurus, Diplodocusw, Etc. Sub-Order Opisthocœlia (Cetiosauria or Sauropoda] by W. D. Matthew, who is credited amongst other accomplishments as authorship of the family Dromaeosauridae, and former Curator of Vertebrate Paleontology at the American Museum of Natural History in New York; Originally published in 1915
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[[Category:Dinosaurs of North America]]
[[Category:Diplodocoids]]
[[Category:Jurassic dinosaurs]]
[[Category:Morrison fauna]]
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