View source for Brontosaurus

{{Short description|Genus of diplodocid sauropod dinosaur}}
{{About|the dinosaur|other uses}}
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{{Use mdy dates|date=October 2023}}
{{Automatic taxobox
| fossil_range = [[Late Jurassic]] ([[Kimmeridgian]] to [[Tithonian]]), {{Geological range|156.3|146.8}}
| image = Brontosaurus excelsus remount in the Peabody Museum.jpg
| image_caption = [[Holotype]] specimen of ''B. excelsus'' (YPM 1980), [[Peabody Museum of Natural History]], as remounted in 2020
| taxon = Brontosaurus
| authority = [[Othniel Charles Marsh|Marsh]], 1879
| type_species = {{extinct}}'''''Brontosaurus excelsus'''''
| type_species_authority = Marsh, 1879
| subdivision_ranks = Other species
| subdivision = 
* {{extinct}}'''''Brontosaurus parvus''''' <br /><small>(Peterson & Gilmore, 1902)</small>
* {{extinct}}'''''Brontosaurus yahnahpin''''' <br /><small>(Filla & Redman, 1994)</small>
| synonyms =
* ''Elosaurus'' <small>Peterson & Gilmore, 1902</small>
* ''Eobrontosaurus'' <small>Bakker, 1998</small>
{{collapsible list|bullets=true
 |title=<small>Synonyms of ''B. excelsus''</small>
| ''Brontosaurus amplus''<br/><small>Marsh, 1881</small>
| ''Apatosaurus excelsus''<br/><small>(Marsh, 1879) Riggs, 1903</small>
| ''Apatosaurus amplus''<br/><small>(Marsh, 1881) Riggs, 1903</small>
| ''Atlantosaurus excelsus''<br/><small>(Marsh, 1879) Steel, 1970</small>
| ''Atlantosaurus amplus''<br/><small>(Marsh, 1881) Steel, 1970</small>
}}
{{collapsible list|bullets=true
 |title=<small>Synonyms of ''B. parvus''</small>
| ''Elosaurus parvus''<br/><small>Peterson & Gilmore, 1902</small>
| ''Apatosaurus parvus''<br/><small>(Peterson & Gilmore, 1902) Upchurch et al., 2004</small>
}}
{{collapsible list|bullets=true
 |title=<small>Synonyms of ''B. yahnahpin''</small>
| ''Apatosaurus yahnahpin''<br/><small>Filla & Redman, 1994</small>
| ''Eobrontosaurus yahnahpin''<br/><small>(Filla & Redman, 1994) Bakker, 1998</small>
}}
}}

'''''Brontosaurus''''' ({{IPAc-en|ˌ|b|r|ɒ|n|t|ə|ˈ|s|ɔːr|ə|s}};{{refn|{{Cite encyclopedia |url=http://www.lexico.com/definition/Brontosaurus |archive-url=https://web.archive.org/web/20200814145305/https://www.lexico.com/definition/brontosaurus |url-status=dead |archive-date=August 14, 2020 |title=Brontosaurus |dictionary=[[Lexico]] UK English Dictionary |publisher=[[Oxford University Press]]}}}}{{refn|{{MerriamWebsterDictionary|access-date=January 21, 2016|Brontosaurus}}}} meaning "thunder lizard" from the [[Ancient Greek|Greek]] words {{lang|grc|βροντή}}, {{transliteration|grc|brontē}} "thunder" and {{lang|grc|σαῦρος}}, {{transliteration|grc|sauros}} "lizard") is a [[genus]] of [[herbivorous]] [[sauropod]] [[dinosaur]] that lived in present-day [[United States]] during the [[Late Jurassic]] period. It was described by American [[paleontologist]] [[Othniel Charles Marsh]] in 1879, the [[type species]] being dubbed '''''B. excelsus''''', based on a partial skeleton lacking a [[skull]] found in [[Como Bluff]], [[Wyoming]]. In subsequent years, two more [[species]] of ''Brontosaurus'' were named: ''B. parvus'' in 1902 and ''B. yahnahpin'' in 1994. ''Brontosaurus'' lived about 156 to 146 million years ago (mya) during the [[Kimmeridgian]] and [[Tithonian]] ages in the [[Morrison Formation]] of what is now [[Utah]] and Wyoming. For decades, the animal was thought to have been a [[Synonym (taxonomy)|taxonomic synonym]] of its close relative ''[[Apatosaurus]]'', but a 2015 study by Emmanuel Tschopp and colleagues found it to be distinct. It has seen widespread representation in popular culture, being the archetypal "long-necked" dinosaur in general media.
The [[anatomy]] of ''Brontosaurus'' is well known, with fossils demonstrating that it was large, long-necked, and [[quadrupedal]] with a long tail terminating in a whip-like structure. The [[cervical vertebrae]] are notably extremely robust and heavily-built, in contrast to its lightly built relatives ''[[Diplodocus]]'' and ''[[Barosaurus]]''. The forelimbs were short and stout whereas the hindlimbs were elongated and thick, supported respectively by a heavily built [[shoulder girdle]] and [[pelvis]]. Several size estimates have been made, with the largest species ''B. excelsus'' reaching up to {{convert|21|-|23|m|ft|abbr=on}} from head to tail and weighing in at {{convert|15|-|20|t|ST|abbr=on}}, whereas the smaller ''B. parvus'' only got up to {{cvt|19|m|ft}} long. Juvenile specimens of ''Brontosaurus'' are known, with younger individuals growing rapidly to adult size in as little as 15 years.

''Brontosaurus'' has been classified within the family [[Diplodocidae]], which was a group of sauropods that had shorter necks and longer tails compared to other families like [[brachiosaurs]] and [[mamenchisaurs]]. Diplodocids first evolved in the [[Middle Jurassic]] but peaked in diversity during the Late Jurassic with forms like ''Brontosaurus'' before becoming extinct in the Early Cretaceous. ''Brontosaurus'' is a genus in the subfamily [[Apatosaurinae]], which includes only it and ''Apatosaurus,'' which are distinguished by their firm builds and thick necks. Although Apatosaurinae was named in 1929, the group was not used [[Valid name (zoology)|validly]] until an extensive 2015 paper, which found ''Brontosaurus'' to be valid. However, the status of ''Brontosaurus'' is still uncertain, with some paleontologists still considering it a synonym of ''Apatosaurus''.

Being from the Morrison Formation, ''Brontosaurus'' coexisted with a menagerie of other taxa such as the sauropods ''Diplodocus, Barosaurus,'' and ''[[Brachiosaurus]];'' herbivorous [[ornithischia]]ns ''[[Stegosaurus]], [[Dryosaurus]],'' and ''[[Nanosaurus]];'' as well as the carnivorous [[theropods]] ''[[Allosaurus]], [[Marshosaurus]]'' and ''[[Ceratosaurus]]''. This formation was a hotspot of sauropod biodiversity, with over 16 recognized genera, which resulted in niche partitioning between different sauropods.

==History of discovery==
[[File:Brontosaurus skeleton 1880s.jpg|thumb|left|An 1896 diagram of the ''B. excelsus'' holotype skeleton by [[Othniel Charles Marsh|O.C. Marsh]]. The head is based on material now assigned to ''[[Brachiosaurus]]'' sp.]]

The discovery of a large and fairly complete [[Sauropoda|sauropod]] skeleton was announced in 1879 by [[Othniel Charles Marsh]], a professor of paleontology at [[Yale University]]. The specimen was collected from [[Morrison Formation]] rocks at [[Como Bluff]], [[Wyoming]] by [[William Harlow Reed]]. He identified it as belonging to an entirely new genus and species, which he named ''Brontosaurus excelsus'',<ref name="marsh1879">{{cite journal|last=Marsh|first=O. C.|s2cid=131001110|year=1879|title=Notice of new Jurassic reptiles|url=http://marsh.dinodb.com/marsh/Marsh%201879%20-%20Notice%20of%20new%20Jurassic%20reptiles.pdf|journal=American Journal of Science|volume=18|issue=108|pages=501–505|doi=10.2475/ajs.s3-18.108.501|bibcode=1879AmJS...18..501M|archive-date=October 9, 2022|access-date=April 7, 2015|archive-url=https://ghostarchive.org/archive/20221009/http://marsh.dinodb.com/marsh/Marsh%201879%20-%20Notice%20of%20new%20Jurassic%20reptiles.pdf|url-status=dead}}</ref> meaning "thunder lizard", from the Greek {{transliteration|grc|brontē}}/{{lang|grc|βροντη}} meaning "thunder" and {{transliteration|grc|sauros}}/{{lang|grc|σαυρος}} meaning "lizard",<ref name="liddell">{{cite book | url=https://archive.org/stream/greekenglishlex00lidduoft#page/iv/mode/2up | title=A Greek-English Lexicon | publisher=Harper & Brothers | last1=Liddell | first1=G. H. | last2=Scott | first2=R. | year=1882 | pages=1–1774}}</ref> and from the [[Latin]] ''excelsus'', "noble" or "high".<ref name="LatDict">{{cite web | url=http://www.latin-dictionary.net/search/latin/excelsus | title=Latin Definitions for: ''excelsus'' (Latin search) | publisher=LatDict Latin Dictionary and Grammar Resources | last=Mahoney | first=K. D. | year=2015}}</ref> By this time, the Morrison Formation had become the center of the [[Bone Wars]], a fossil-collecting rivalry between Marsh and another early paleontologist, [[Edward Drinker Cope]]. Because of this, the publications and descriptions of taxa by Marsh and Cope were rushed at the time.<ref name="BMunpublished">{{cite journal | url=https://www.academia.edu/455778 | archive-url=https://archive.today/20150128052844/http://www.academia.edu/455778/A_review_of_Morrison_Formation_upper_Jurassic_USA_sauropod_dinosaurs | url-status=dead | archive-date=January 28, 2015 | title=The Sauropod Dinosaurs of the Morrison Formation (Upper Jurassic, USA): A Review | last=Moon | first=B. | journal=Dinosauria | year=2010 | pages=1–9 }}</ref> ''Brontosaurus excelsus''{{'}} type specimen ([[Peabody Museum of Natural History|YPM]] 1980) was one of the most complete sauropod skeletons known at the time, preserving many of the characteristic but fragile cervical vertebrae.<ref name="Marsh">{{Cite book |last=Marsh |first=Othniel Charles |url=https://books.google.com/books?id=_15AAQAAIAAJ&pg=PA139 |title=The Dinosaurs of North America |publisher=U.S. Government Printing Office |year=1896 |language=en}}</ref> Marsh believed that ''Brontosaurus'' was a member of the [[Diplodocidae|Atlantosauridae]], a clade of sauropod dinosaurs he named in 1877 that also included ''[[Atlantosaurus]]'' and ''[[Apatosaurus]]''.<ref name="Marsh" /> A year later in 1880, another partial postcranial ''Brontosaurus'' skeleton was collected near Como Bluff by Reed,<ref>{{Cite web |last=Marsh |first=Othniel Charles |title=Apatosaurus excelsus; YPM VP 001981; North America; USA; Wyoming; Albany County; William H. Reed, Reed-Como party, 1880; 1880 |url=https://collections.peabody.yale.edu/search/Record/YPM-VP-001981 |access-date=March 10, 2022 |website=collections.peabody.yale.edu |language=en |archive-date=January 28, 2023 |archive-url=https://web.archive.org/web/20230128003616/https://collections.peabody.yale.edu/search/Record/YPM-VP-001981 |url-status=live }}</ref><ref name="Marsh-1881">{{Cite journal |last=Marsh |first=Othniel Charles |date=May 1, 1881 |title=Principal characters of American Jurassic dinosaurs, Part V |url=https://www.ajsonline.org/content/s3-21/125/417 |journal=American Journal of Science |language=en |volume=s3-21 |issue=125 |pages=417–423 |doi=10.2475/ajs.s3-21.125.417 |bibcode=1881AmJS...21..417M |s2cid=219234316 |issn=0002-9599 |access-date=March 10, 2022 |archive-date=March 14, 2021 |archive-url=https://web.archive.org/web/20210314105011/https://www.ajsonline.org/content/s3-21/125/417 |url-status=dead |url-access=subscription }}</ref> including well-preserved limb elements.<ref name="TMB2015" /> Marsh named this second skeleton ''Brontosaurus amplus'' ("large thunder lizard") in 1881,<ref name="Marsh-1881" /> but it was considered a synonym of ''B. excelsus'' in 2015.<ref name="TMB2015" />

In August 1883, [[Marshall P. Felch]] collected a disarticulated partial [[skull]] (USNM V 5730) of a sauropod further south in the Felch Quarry at [[Garden Park, Colorado|Garden Park]], [[Colorado]] and sent the specimen to Yale.<ref name="carpenter98">{{cite book |last1=Carpenter |first1=Kenneth |title=The Upper Jurassic Morrison Formation: an interdisciplinary study |last2=Tidwell |first2=Virginia |publisher=Taylor & Francis |year=1998 |isbn=978-90-5699-183-8 |editor1-last=Carpenter |editor1-first=Kenneth |chapter=Preliminary Description of a Brachiosaurus Skull from Felch Quarry 1, Garden Park, Colorado |editor2-last=Chure |editor2-first=Dan |editor3-last=Kirkland |editor3-first=James Ian |chapter-url=https://books.google.com/books?id=CLEPeg_SjTcC&pg=PA69}}</ref><ref name="D'Emic-2019">{{Cite journal |last1=D'Emic |first1=Michael D. |last2=Carrano |first2=Matthew T. |date=June 28, 2019 |title=Redescription of Brachiosaurid Sauropod Dinosaur Material From the Upper Jurassic Morrison Formation, Colorado, USA |journal=The Anatomical Record |volume=303 |issue=4 |pages=732–758 |doi=10.1002/ar.24198 |pmid=31254331 |s2cid=195765189 |issn=1932-8486|doi-access=free }}</ref> Marsh referred the skull to ''B. excelsus'',<ref name="carpenter98" /><ref name="Marsh-2">{{Cite journal |last=Marsh |first=O. C. |year=1891 |title=Restoration of Brontosaurus |journal=American Journal of Science |volume=s3-41 |pages=341–342}}</ref> later featuring it in a skeletal reconstruction of the ''B. excelsus'' type specimen in 1891<ref name="Marsh-2" /> and the illustration was featured again in Marsh's landmark publication, ''The Dinosaurs of North America'', in 1896.<ref name="Marsh" /> At the [[Yale Peabody Museum]], the skeleton of ''Brontosaurus excelsus'' was mounted in 1931 with a skull based on the Marsh reconstruction of the Felch Quarry skull.<ref name="camarasaurusbully" /> While at the time most museums were using ''[[Camarasaurus]]'' casts for skulls, the Peabody Museum sculpted a completely different skull based on Marsh's recon.<ref name="camarasaurusbully" /><ref name="carpenter98" /> Marsh's skull was inaccurate for several other reasons: it included forward-pointing nasals, something truly different to any other dinosaur, and fenestrae differing from the drawing and other skulls. The mandible was based on a ''Camarasaurus''<nowiki/>'.<ref name="camarasaurusbully" /> In 1998, the Felch Quarry skull that Marsh included in his 1896 skeletal restoration was suggested to belong to ''[[Brachiosaurus]]'' instead<ref name="carpenter98" /> and this was supported in 2020 with a redescription of the [[Brachiosauridae|brachiosaurid]] material found at the Felch Quarry.<ref name="D'Emic-2019" />

=== Second Dinosaur Rush and skull issue ===
[[File:Annual report of the American Museum of Natural History for the year (1901) (18426246345).jpg|thumb|left|Obsolete mount of an apatosaurine referred to ''B. excelsus'' (specimen AMNH 460) with sculpted skull, completed in 1905, [[American Museum of Natural History]]]]

During a [[Carnegie Museum of Natural History|Carnegie Museum]] expedition to Wyoming in 1901, William Harlow Reed collected another ''Brontosaurus'' skeleton, a partial postcranial skeleton of a young juvenile (CM 566), including partial limbs. However, this individual was found intermingled with a fairly complete skeleton of an adult (UW 15556).<ref name="Peterson-1902">{{Cite journal |last1=Peterson |first1=Olof August |last2=Gilmore |first2=Charles W. |date=March 1902 |title=Elosaurus parvus: a new genus and species of the Sauropoda |url=https://www.biodiversitylibrary.org/part/78087 |journal=Annals of the Carnegie Museum |volume=1 |issue=3 |pages=490––499 |doi=10.5962/p.78087 |s2cid=145874092 |issn=0097-4463|doi-access=free |bibcode=1902AnCM....1..490P }}</ref> The adult skeleton specifically was very well-preserved, bearing many cervical (neck) and caudal (tail) vertebrae, and is the most complete definite specimen of the species.<ref name="TMB2015" /> The skeletons were granted a new genus and species name, ''Elosaurus parvus'' ("little field lizard"), by Olof A. Peterson and [[Charles W. Gilmore|Charles Gilmore]] in 1902.<ref name="Peterson-1902" /> Both of the specimens came from the Brushy Basin Member of the Morrison Formation. The species was later transferred to ''Apatosaurus'' by several authors<ref name="Tschopp">Tschopp, E., Mateus, O., & Benson, R. B. (2015). [https://peerj.com/articles/857/ A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda).] {{Webarchive|url=https://web.archive.org/web/20150518172938/https://peerj.com/articles/857/ |date=May 18, 2015 }} ''PeerJ'', ''3'', e857.</ref><ref name="Upchurch05" /> In 2008, a nearly complete postcranial skeleton of an [[Apatosaurinae|apatosaurine]] was collected in Utah by crews working for [[Brigham Young University]] (BYU 1252-18531) where some of the remains are currently on display.<ref name="TMB2015" /> The skeleton is undescribed, but many of the features of the skeleton are shared with ''A. parvus''.<ref name="TMB2015" /> The species was placed in ''Brontosaurus'' Tschopp ''et al''. in 2015 during their comprehensive study of [[Diplodocidae]].<ref name="Science Daily-2015" /><ref name="TMB2015" />

[[File:Brontosaurus infographic.jpg|thumb|[[Infographic]] explaining the history of ''Brontosaurus'' and ''Apatosaurus'' according to Tschopp et al. 2015]]

In the 1903 edition of ''Geological Series of the Field Columbian Museum,'' [[Elmer S. Riggs|Elmer Riggs]] argued that ''Brontosaurus'' was not different enough from ''Apatosaurus'' to warrant a separate genus, so he created the new combination ''Apatosaurus excelsus'' for it. Riggs stated that "In view of these facts the two genera may be regarded as synonymous. As the term {{'}}''Apatosaurus''{{'}} has priority, {{'}}''Brontosaurus''{{'}} will be regarded as a synonym".<ref name="riggs-1903" /> Nonetheless, before the mounting of the American Museum of Natural History specimen, [[Henry Fairfield Osborn]] chose to label the skeleton "''Brontosaurus''", though he was a strong opponent of Marsh and his taxa.<ref name="camarasaurusbully">{{cite web | url=https://dinosours.wordpress.com/2014/10/30/bully-for-camarasaurus/ | title=Bully for ''Camarasaurus'' | publisher=Dinosours | date=October 30, 2014 | last=Miller | first=B.}}</ref><ref name="parsons">{{cite journal | url=http://www.carnegiemuseums.org/cmag/bk_issue/1997/novdec/feat5.htm | title=The Wrongheaded Dinosaur | last=Parsons | first=K. M. | journal=Carnegie Magazine | year=1997 | url-status=dead | archive-url=https://web.archive.org/web/20100414165426/http://www.carnegiemuseums.org/cmag/bk_issue/1997/novdec/feat5.htm | archive-date=April 14, 2010 }}</ref>
In 1905, the [[American Museum of Natural History]] (AMNH) unveiled the first-ever mounted skeleton of a sauropod, a composite specimen (mainly made of bones from AMNH 460) that they referred to as ''Brontosaurus excelsus''. The AMNH specimen was very complete, only missing the feet, from the specimen AMNH 592 were added to the mount, lower leg and shoulder bones, added from AMNH 222, and tail bones, added from AMNH 339.<ref name="discoveringAMNH">Norell, M.A., Gaffney, E.S., & Dingus, L. (1995). ''Discovering Dinosaurs in the American Museum of Natural History''. New York: Alfred A. Knopf, Inc.</ref> To finish the mount, the rest of the tail was fashioned to appear as Marsh believed it should, which meant it had too few vertebrae. In addition, a sculpted model of what the museum felt the skull of this massive creature might have looked like was placed on the skeleton. This was not a delicate skull like that of ''[[Diplodocus]]'', which would later turn out to be more accurate, but was based on "the biggest, thickest, strongest skull bones, lower jaws, and tooth crowns from three different quarries".<ref name="gilmore36" /><ref name="riggs-1903" /><ref name="Bakker">{{cite journal | url=http://connection.ebscohost.com/c/articles/9409020826/bite-bronto | archive-url=https://web.archive.org/web/20150209044223/http://connection.ebscohost.com/c/articles/9409020826/bite-bronto | url-status=dead | archive-date=February 9, 2015 | title=The Bite of the Bronto | last=Bakker | first=R. T. | journal=Earth | year=1994 | volume=3 | issue=6 | pages=26–33}}</ref><ref name="mcintosh&berman1975">{{cite journal | title=Description of the Palate and Lower Jaw of the Sauropod Dinosaur ''Diplodocus'' (Reptilia: Saurischia) with Remarks on the Nature of the Skull of ''Apatosaurus'' | last1=McIntosh | first1=J. S. | last2=Berman | first2=D. S. | journal=Journal of Paleontology | issue=1 | jstor=1303324 | year=1975 | volume=49 | pages=187–199}}</ref> These skulls were likely those of ''Camarasaurus'', the only other sauropod of which good skull material was known at the time. The mount construction was overseen by Adam Hermann, who failed to find ''Brontosaurus'' skulls. Hermann was forced to sculpt a stand-in skull by hand. Henry Fairfield Osborn noted in a publication that the skull was "largely conjectural and based on that of ''Morosaurus''" (now ''Camarasaurus'').<ref name="camarasaurusbully" />

In 1909, an ''Apatosaurus'' skull was found, during the first expedition to what would become the Carnegie Quarry at [[Dinosaur National Monument]], led by Earl Douglass. The skull was found a few meters away from a skeleton (specimen CM 3018) identified as the new species ''[[Apatosaurus louisae]]''. The skull was designated CM 11162 and was very similar to the skull of ''Diplodocus''. It was accepted as belonging to the ''Apatosaurus'' specimen by Douglass and Carnegie Museum director [[William Jacob Holland|William J. Holland]], although other scientists, most notably Osborn, rejected this identification. Holland defended his view in 1914 in an address to the [[Paleontological Society|Paleontological Society of America]], yet he left the Carnegie Museum mount headless. While some thought Holland was attempting to avoid conflict with Osborn, others suspected that Holland was waiting until an articulated skull and neck were found to confirm the association of the skull and skeleton.<ref name="camarasaurusbully" /> After Holland's death in 1934, a cast of a ''Camarasaurus'' skull was placed on the mount by museum staff.<ref name="parsons" />

=== Skull correction, resurgent discoveries, and reassessment ===
[[File:Yale Peabody Apatosaurus skull sculpt.jpg|left|thumb|The sculpted "''Brontosaurus''" skull of the [[Peabody Museum of Natural History|Yale Peabody Museum]] mount, which was based on fossils ''[[Camarasaurus]]'' and ''[[Brachiosaurus]]'']]

No apatosaurine skull was mentioned in the literature until the 1970s when John Stanton McIntosh and David Berman redescribed the skulls of ''Diplodocus'' and ''Apatosaurus'' in 1975.<ref name="mcintosh&berman1975" /> They found that though he never published his opinion, Holland was almost certainly correct in that ''Apatosaurus'' and ''Brontosaurus'' had a ''Diplodocus''-like skull.<ref name="mcintosh&berman1975" /> According to them, many skulls long thought to belong to ''Diplodocus'' might instead be those of ''Apatosaurus''.<ref name="mcintosh&berman1975" /> They reassigned multiple skulls to ''Apatosaurus'' based on associated and closely associated vertebrae.<ref name="mcintosh&berman1975" /> Though they supported Holland, ''Apatosaurus'' was falsely theorized to possibly have possessed a ''Camarasaurus''-like skull, based on a disarticulated ''Camarasaurus''-like tooth found at the precise site where an ''Apatosaurus'' specimen was found years before.<ref name="mcintosh&berman1975" /> However, this tooth does not come from ''Apatosaurus''.<ref name=":1" /> On October 20, 1979, after the publications by McIntosh and Berman, the first skull of an ''Apatosaurus'' was mounted on a skeleton in a museum, that of the Carnegie.<ref name="parsons" /> In 1995, the American Museum of Natural History followed suit, and unveiled their remounted skeleton (now labelled ''Apatosaurus excelsus'') with a corrected tail and a new skull cast from ''A. louisae''.<ref name="discoveringAMNH" /> In 1998, [[Robert T. Bakker]] referred a skull and mandible of an apatosaurine from Como Bluff to ''Brontosaurus excelsus'' ([[Tate Geological Museum|TATE]] 099-01)'','' though the skull is still undescribed.<ref name="Bakker98" /> In 2011, the first specimen of ''Apatosaurus'' where a skull was found articulated with its cervical vertebrae was described. This specimen, [[Cincinnati Museum Center|CMC]] VP 7180, was found to differ in both skull and neck features from ''A. louisae'', and the specimen was found to have a majority of features related to those of ''A. ajax''.<ref name="barrettetal11">{{cite journal |last1=Barrett |first1=P. M. |last2=Storrs |first2=G. W. |last3=Young |first3=M. T. |last4=Witmer |first4=L. M. |year=2011 |title=A new skull of ''Apatosaurus'' and its taxonomic and palaeobiological implications |url=http://www.miketaylor.org.uk/dino/pubs/svpca2011/SVPCA2011-abstracts.pdf |journal=Symposium of Vertebrate Palaeontology & Comparative Anatomy Abstracts of Presentations |page=5 |archive-date=October 9, 2022 |access-date=April 7, 2015 |archive-url=https://ghostarchive.org/archive/20221009/http://www.miketaylor.org.uk/dino/pubs/svpca2011/SVPCA2011-abstracts.pdf |url-status=live }}</ref>

[[File:Brontosaurus Yale Peabody cropped.jpg|thumb|upright|The Peabody Museum mount with new skull but in its original pose before its 2020 remounting]]

Another specimen of an Apatosaurine now referred to ''Brontosaurus'' was discovered in 1993 by the [[Tate Geological Museum]], also from the Morrison Formation of central Wyoming. The specimen consisted of a partial postcranial skeleton, including a complete manus and multiple vertebrae, and was described by James Filla and Pat Redman a year later.<ref name="Bakker98" /> Filla and Redman named the specimen ''Apatosaurus yahnahpin'' ("yahnahpin-wearing deceptive lizard"), but [[Robert T. Bakker]] gave it the genus name ''Eobrontosaurus'' in 1998.<ref name="Bakker98" /> Bakker believed that ''Eobrontosaurus'' was the direct predecessor to ''Brontosaurus,''<ref name="Bakker98" /> although Tschopp ''et al''.'s phylogenetic analysis placed ''B. yahnahpin'' as the basalmost species of ''Brontosaurus''.<ref name="TMB2015" />

Almost all 20th-century paleontologists agreed with Riggs that all ''Apatosaurus'' and ''Brontosaurus'' species should be classified in a single genus. According to the rules of the [[International Code of Zoological Nomenclature|ICZN]], which governs the scientific names of animals, the name ''Apatosaurus'', having been published first, had priority; ''Brontosaurus'' was considered a [[Synonym (taxonomy)|junior synonym]] and was therefore discarded from formal use.<ref name="taylor10">{{cite journal | url=http://www.miketaylor.org.uk/dino/pubs/taylor2010/Taylor2010-sauropod-history.pdf | title=Sauropod dinosaur research: a historical review | last=Taylor | first=M. P. | s2cid=910635 | author-link=Mike P. Taylor | journal=Geological Society, London, Special Publications | year=2010 | volume=343 | doi=10.1144/SP343.22 | issue=1 | pages=361–386 | bibcode=2010GSLSP.343..361T | archive-date=October 9, 2022 | access-date=April 7, 2015 | archive-url=https://ghostarchive.org/archive/20221009/http://www.miketaylor.org.uk/dino/pubs/taylor2010/Taylor2010-sauropod-history.pdf | url-status=live }}</ref><ref name="endeavour">{{cite journal | title=Bully for ''Apatosaurus'' | last=Brinkman | first=P. | journal=Endeavour | year=2006 | volume=30 | issue=4 | pages=126–130 | doi=10.1016/j.endeavour.2006.10.004 | pmid=17097734}}</ref><ref name="Dinosauria04">{{cite book | chapter=Sauropoda | editor=Weishampel, D. B. |editor2=Osmólska, H. |editor3=Dodson, P. | title=The Dinosauria | publisher=University of California Press | last1=Upchurch | first1=P. | last2=Barrett | first2=P. M. | last3=Dodson | first3=P. | year=2004 | edition=2 | pages=259–322}}</ref><ref name="Macintosh">{{cite journal | editor=A. Sun |editor2=Y. Wang | title=Remarks on the North American sauropod ''Apatosaurus'' Marsh | last=McIntosh | first=J. S. | journal=Sixth Symposium on Mesozoic Terrestrial Ecosystems and Biota Short Papers | year=1995 | pages=119–123}}</ref> Despite this, at least one paleontologist—Robert T. Bakker—argued in the 1990s that ''A. ajax'' and ''A. excelsus'' are sufficiently distinct that the latter continues to merit a separate genus.<ref name="Bakker98">{{cite book | chapter=Dinosaur mid-life crisis: the Jurassic-Cretaceous transition in Wyoming and Colorado | chapter-url=http://econtent.unm.edu/cdm/ref/collection/bulletins/id/928 | editor-first=Spencer G. | editor-last=Lucas | editor2-first=James I. | editor2-last=Kirkland | editor3-first=J. W. | editor3-last=Estep | title=Lower and Middle Cretaceous Terrestrial Ecosystems | publisher=New Mexico Museum of Natural History and Science Bulletin | last=Bakker | first=R. T. | year=1998 | volume=14 | pages=67–77 | archive-date=November 19, 2018 | access-date=April 7, 2015 | archive-url=https://web.archive.org/web/20181119210410/http://econtent.unm.edu/cdm/ref/collection/bulletins/id/928 | url-status=live }}</ref> In 2015, an extensive study of diplodocid relationships by Emanuel Tschopp, Octavio Mateus, and Roger Benson concluded that ''Brontosaurus'' was indeed a valid genus of sauropod distinct from ''Apatosaurus''. The scientists developed a statistical method to more objectively assess differences between fossil genera and species and concluded that ''Brontosaurus'' could be "resurrected" as a valid name. They assigned two former ''Apatosaurus'' species, ''A. parvus,'' and ''A. yahnahpin'', to ''Brontosaurus'', as well as the type species ''B. excelsus''.<ref name="TMB2015" /> The publication was met with some criticism from other paleontologists, including Michael D'Emic,<ref>{{Cite magazine |last=D'Emic |first=Michael |date=April 9, 2015 |title=Not So Fast, Brontosaurus |url=https://time.com/3810104/not-so-fast-brontosaurus/ |access-date=July 9, 2023 |magazine=Time |language=en |archive-date=October 20, 2020 |archive-url=https://web.archive.org/web/20201020180243/https://time.com/3810104/not-so-fast-brontosaurus/ |url-status=live }}</ref> [[Donald Prothero]], who criticized the mass media reaction to this study as superficial and premature,<ref name="prothero 2015">Prothero, D. 2015. [http://www.skeptic.com/insight/is-brontosaurus-back-not-so-fast/ "Is "Brontosaurus" Back? Not So Fast!"]. Skeptic.com</ref> and many others [[#In popular culture|below]]. Some paleontologists, such as [[John Foster (paleontologist)|John]] and [[ReBecca Hunt-Foster|ReBecca Foster]], continue to consider ''Brontosaurus'' as a synonym of ''Apatosaurus''.<ref>{{Cite journal |last1=Foster |first1=John R. |last2=Peterson |first2=Joseph E. |date=September 1, 2016 |title=First report of Apatosaurus (Diplodocidae: Apatosaurinae) from the Cleveland-Lloyd Quarry in the Upper Jurassic Morrison Formation of Utah: Abundance, distribution, paleoecology, and taphonomy of an endemic North American sauropod clade |url=https://www.sciencedirect.com/science/article/pii/S1871174X15000906 |journal=Palaeoworld |language=en |volume=25 |issue=3 |pages=431–443 |doi=10.1016/j.palwor.2015.11.006 |issn=1871-174X|url-access=subscription }}</ref><ref>{{Cite journal |last1=Foster |first1=John |last2=Hunt-Foster |first2=ReBecca |last3=Gorman |first3=Mark |last4=Trujillo |first4=Kelli |last5=Suarez |first5=Celina |last6=McHugh |first6=Julia |last7=Peterson |first7=Joseph |last8=Warnock |first8=Jonathan |last9=Schoenstein |first9=Heidi |date=April 19, 2018 |title=Paleontology, taphonomy, and sedimentology of the Mygatt-Moore Quarry, a large dinosaur bonebed in the Morrison Formation, western Colorado—Implications for Upper Jurassic dinosaur preservation modes |url=https://giw.utahgeology.org/giw/index.php/GIW/article/view/24 |journal=Geology of the Intermountain West |language=en |volume=5 |pages=23–93 |doi=10.31711/giw.v5.pp23-93 |issn=2380-7601|doi-access=free }}</ref>

==Description==
[[File:Apatosaurus scale mmartyniuk wiki.png|thumb|left|Comparison of three specimens and a human: Oklahoma specimen of ''[[Apatosaurus ajax]]'' (orange), ''A. louisae'' (red), and ''Brontosaurus parvus'' (green)]]
''Brontosaurus'' was a large, long-necked, [[quadruped]]al animal with a long, whip-like tail, and forelimbs that were slightly shorter than its hindlimbs. The largest species, ''B. excelsus'', measured up to {{convert|21|-|23|m|ft|abbr=on}} long from head to tail and weighed up to {{convert|15|-|20|t|ST|abbr=on}}; other species were smaller, measuring {{cvt|19|m|ft}} long and weighing {{cvt|14|MT|ST}}.<ref name="GSP10">{{cite book|last=Paul|first=Gregory S.|title=Princeton Field Guide to Dinosaurs|url=https://archive.org/details/princetonfieldgu0000paul|url-access=registration|year=2010|publisher=Princeton University Press|isbn=978-0-691-13720-9}}</ref><ref>{{cite book|last1=Molina-Pérez|first1=R.|last2=Larramendi|first2=A.|year=2020|title=Dinosaur Facts and Figures: The Sauropods and Other Sauropodomorphs|pages=256|publisher=Princeton University Press|isbn=978-0-691-19069-3}}</ref><ref>Paul, G.S. (2024) ''The Princeton Field Guide to Dinosaurs''. 3nd ed. [[Princeton University Press]] p. 238</ref> The skull of ''Brontosaurus'' has not been found but was probably similar to the skull of the closely related ''Apatosaurus''. Several skulls of ''Apatosaurus'' have been found, all of which are very small in proportion to the body. Their snouts were squared off and low, in contrast to [[Macronaria|macronarians']].<ref name=":0" /> Jaws of ''Apatosaurus'' and other diplodocids were lined with spatulate (chisel-like) teeth which were adapted for herbivory.<ref name=":1">{{Cite journal |last1=Peterson |first1=Joseph E. |last2=Lovelace |first2=David |last3=Connely |first3=Melissa |last4=McHugh |first4=Julia B. |date=2022 |title=A novel feeding mechanism of diplodocid sauropods revealed in an Apatosaurine skull from the Upper Jurassic Nail Quarry (Morrison Formation) at Como Bluff, Wyoming, USA |url=https://palaeo-electronica.org/content/2022/3653-apatosaurine-feeding-mechanism |journal=Palaeontologia Electronica |language=English |volume=25 |issue=2 |pages=1–23 |doi=10.26879/1216 |s2cid=251174364 |issn=1094-8074|doi-access=free }}</ref><ref name="barrettetal11" />

=== Vertebrae ===

[[File:The dinosaurs of North America (7368691314).jpg|thumb|upright|A cervical (top) and dorsal vertebra (bottom) of ''B. excelsus'']]
Like those of other diplodocids, the vertebrae of the neck were deeply bifurcated on the dorsal side; that is, they carried paired spines, resulting in a wide and deep neck.<ref name="fastovsky">{{cite book | url=http://www.evolbiol.ru/large_files/dinosaurs2009.pdf | title=Dinosaurs: A Concise Natural History | publisher=Cambridge University Press | last1=Fastovsky | first1=D. E. | last2=Weishampel | first2=D. B. | year=2009 | pages=165–200 | isbn=978-0-521-88996-4 | archive-date=September 24, 2015 | access-date=April 7, 2015 | archive-url=https://web.archive.org/web/20150924004505/http://www.evolbiol.ru/large_files/dinosaurs2009.pdf | url-status=live }}</ref> The spine and tail consisted of 15 cervicals, ten dorsals, five sacrals, and about 82 caudals, based on ''Apatosaurus''. The number of caudal vertebrae has been noted to vary, even within a species. Vertebrae in the neck, torso, and sacrum of sauropods bore large [[Glossary of dinosaur anatomy|pneumatic foramina]] on their lateral sides.<ref name="Marsh-1881" /> These are used to lighten the bones which aided in keeping the animal lighter. Within the vertebrae as well, smooth bone walls in addition to [[Diverticulum|diverticula]] would make pockets of air to keep the bones light.<ref>Wedel, M. J. (2005). Postcranial skeletal pneumaticity in sauropods and its implications for mass estimates. ''The sauropods: evolution and paleobiology. University of California Press, Berkeley'', 201-228.</ref> Similar structures are observable in birds and large mammals.<ref>{{cite journal | url=https://onlinelibrary.wiley.com/doi/abs/10.1002/jmor.10470 | doi=10.1002/jmor.10470 | title=Postcranial pneumaticity: An evaluation of soft-tissue influences on the postcranial skeleton and the reconstruction of pulmonary anatomy in archosaurs | year=2006 | last1=O'Connor | first1=Patrick M. | journal=Journal of Morphology | volume=267 | issue=10 | pages=1199–1226 | pmid=16850471 | s2cid=15284762 | url-access=subscription | archive-date=June 17, 2023 | access-date=June 17, 2023 | archive-url=https://web.archive.org/web/20230617150252/https://onlinelibrary.wiley.com/doi/abs/10.1002/jmor.10470 | url-status=live }}</ref> The cervical vertebrae were stouter than those of other diplodocids, as in ''Apatosaurus''. On the lateral sides of the cervicals, apatosaurines had well-developed and thick [[parapophyses]] (extensions on the lateral sides of the vertebrae that attached to cervical ribs) which would point ventrally under the [[Vertebra|centrum]]. These parapophyses in conjunction with dense [[Vertebra|diapophyses]] and [[cervical rib]]s were strong anchors for neck muscles, which could sustain extreme force.<ref name="twne15">{{cite journal |last1=Taylor |first1=M.P. |author-link=Michael P. Taylor |last2=Wedel |first2=M.J. |last3=Naish |first3=Darren |last4=Engh |first4=B. |year=2015 |title=Were the necks of ''Apatosaurus'' and ''Brontosaurus'' adapted for combat? |journal=PeerJ PrePrints |volume=3 |pages=e1663 |doi=10.7287/peerj.preprints.1347v1 |doi-access=free}}</ref> The cervicals were also more boxy than in other sauropods due to their truncated [[Articular processes|zygapophyses]] and tall build.<ref>Wedel, M. J., Sanders, R. K., & Cuozzo, F. P. (2002). ''Osteological correlates of cervical musculature in Aves and Sauropoda (Dinosauria: Saurischia), with comments on the cervical ribs of Apatosaurus''. Museum of Paleontology, University of California, Berkeley.</ref><ref name="TMB2015" /> These vertebrae are triangular in anterior view, whereas they most often are rounded or square in genera like ''Camarasaurus''. Despite its pneumaticy, the neck of ''Brontosaurus'' is thought to have been double the mass of that of other diplodocids due to the former's sturdiness.<ref name="twne15" /> ''Brontosaurus'' differs from ''Apatosaurus'' in that the base of the posterior dorsal vertebrae's [[Vertebra|neural spines]] are longer than they are wide. The cervicals of species within ''Brontosaurus'' also vary, such as the lack of [[Tubercle|tubercules]] on the neural spines of ''B. excelsus'' and the lateral expansion of unbifurcated neural spines in ''B. parvus''.<ref name="TMB2015" />

Its dorsal vertebrae had short centra with large [[Fossa (anatomy)|fossae]] (shallow excavations) on their lateral sides, though not as extensively as the cervicals’.<ref>{{Cite journal |last1=Wedel |first1=Mathew J. |last2=Taylor |first2=Michael P. |date=October 30, 2013 |title=Caudal Pneumaticity and Pneumatic Hiatuses in the Sauropod Dinosaurs Giraffatitan and Apatosaurus |journal=PLOS ONE |language=en |volume=8 |issue=10 |pages=e78213 |doi=10.1371/journal.pone.0078213 |issn=1932-6203 |pmc=3812994 |pmid=24205162 |bibcode=2013PLoSO...878213W |doi-access=free }}</ref> Neural canals, which contain the [[spinal cord]] of the vertebral column, are ovate and large in the dorsals. The diapophyses protrude outward and curve downward in a hook-shape. Neural spines are thick in anterior-posterior view with a bifurcate top.<ref name="TMB2015" /> The neural spines of the dorsals would increase in height further towards the tail, creating an arched back. Apatosaurine neural spines compose more than half the height of the vertebrae. Medial surfaces of neural spines are gently rounded in ''B. yahnahpin'', whereas in other ''B.'' spp. they are not.<ref name="TMB2015" /> The dorsal ribs are not fused or tightly attached to their vertebrae, instead being loosely articulated.<ref name="gilmore36">{{cite journal | title=Osteology of ''Apatosaurus'', with special references to specimens in the Carnegie Museum | last=Gilmore | first=C. W. | author-link=Charles Whitney Gilmore | journal=Memoirs of the Carnegie Museum |date=February 1936 | volume=11 | issue=4 | pages=175–300 | doi=10.5962/p.234849 | s2cid=89649268 | oclc=16777126| doi-access=free }}</ref> Ten [[Rib cage|dorsal ribs]] are on either side of the body.<ref name="riggs-1903" /> Expanded excavations within the [[sacrum]] are present making it into a hollow cylinder-shape. Sacral neural spines are fused together into a thin plate. The posteriormost caudal vertebra was lightly fused to the sacral vertebrae, becoming part of the plate. Internally, the [[Neural tube|neural canal]] was enlarged.<ref name=":2">Osborn, H. F. (1904). ''Manus, sacrum, and caudals of Sauropoda'' (Vol. 3).</ref><ref>{{Cite journal |last1=Moro |first1=Débora |last2=Kerber |first2=Leonardo |last3=Müller |first3=Rodrigo T. |last4=Pretto |first4=Flávio A. |date=2021 |title=Sacral co-ossification in dinosaurs: The oldest record of fused sacral vertebrae in Dinosauria and the diversity of sacral co-ossification patterns in the group |journal=Journal of Anatomy |language=en |volume=238 |issue=4 |pages=828–844 |doi=10.1111/joa.13356 |issn=0021-8782 |pmc=7930772 |pmid=33164207}}</ref><ref name="riggs-1903" /> The shape of the tail was typical of diplodocids, being comparatively slender, due to the vertebral spines rapidly decreasing in height the farther they are from the hips. As in other diplodocids, the last portion of the tail of ''Brontosaurus'' possessed a whip-like structure.<ref name="gilmore36" /> The tail also bears an extensive air-sac system to lighten its weight, as observed in specimens of ''B. parvus''.<ref>{{Cite journal |last1=Taylor |first1=Mike |last2=Wedel |first2=Mathew |date=January 20, 2021 |title=Why is vertebral pneumaticity in sauropod dinosaurs so variable? |url=https://www.qeios.com/read/1G6J3Q |journal=Qeios |language=en |doi=10.32388/1G6J3Q |issn=2632-3834 |doi-access=free |archive-date=September 28, 2023 |access-date=June 11, 2023 |archive-url=https://web.archive.org/web/20230928001050/https://www.qeios.com/read/1G6J3Q |url-status=live }}</ref><ref>{{Cite web |date=February 15, 2021 |title=Happy Valentine's Day from Apatosaurinae |url=https://svpow.com/2021/02/15/happy-valentines-day-from-apatosaurinae/ |access-date=June 10, 2023 |website=Sauropod Vertebra Picture of the Week |language=en |archive-date=June 10, 2023 |archive-url=https://web.archive.org/web/20230610222121/https://svpow.com/2021/02/15/happy-valentines-day-from-apatosaurinae/ |url-status=live }}</ref>

=== Limbs ===
[[File:Brontosaurus by Tom Parker.png|thumb|left|Restoration of ''B. excelsus'']]

Several [[scapula]]e are known from ''Brontosaurus'', all of which are long and thin with relatively elongated shafts.<ref name=":2" /> One of traits that distinguishes ''Brontosaurus'' and ''Apatosaurus'' is the presence of a depression on the posterior face of the scapula, which the latter lacks. The scapula of ''Brontosaurus'' also has a rounded extension off of its edge, a characteristic unique to ''Brontosaurus'' among Apatosaurinae.<ref name="TMB2015" /> The [[coracoid]] anatomy is closely akin to that of ''Apatosaurus'', with a quadratic outline in dorsal view. [[Sternum|Sterna]] have been preserved in some specimens of ''Brontosaurus,'' which display an oval outline.<ref name="Marsh-1881" /> The hip bones include robust [[ilium bone|ilia]] and the fused [[pubic bone|pubes]] and [[ischium|ischia]]. The limb bones were also very robust,<ref name="LHW07">{{cite journal |last1=Lovelace |first1=D. M. |last2=Hartman |first2=S. A. |last3=Wahl |first3=W. 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 |url=https://www.academia.edu/539710 |journal=Arquivos do Museu Nacional |volume=65 |issue=4 |pages=527–544 |issn=0365-4508 |archive-date=July 9, 2021 |access-date=December 2, 2017 |archive-url=https://web.archive.org/web/20210709183218/https://www.academia.edu/539710 |url-status=live }}</ref> with the [[humerus]] resembling that of ''Camarasaurus'', and those of ''B. excelsus'' being nearly identical to those of ''Apatosaurus ajax''. The humerus had a thin [[Anatomical terms of bone|bone shaft]] and larger transverse ends. Its anterior end bears a large [[Humerus|deltopectoral crest]], which was on the extremities of the bone.<ref>{{Cite journal |doi=10.5962/p.247231 |title=Structure of the fore limb and manus of Brontosaurus |year=1902 |last1=Hatcher |first1=J. B. |journal=Annals of the Carnegie Museum |volume=1 |issue=3 |pages=356–376 |s2cid=92181040 |doi-access=free |bibcode=1902AnCM....1..356H }}</ref> 


[[File:Eobrontosaurus yahnahpin.jpg|thumb|upright|Left front limb of ''B. yahnahpin'', [[Morrison Natural History Museum]]]]
Charles Gilmore in 1936 noted that previous reconstructions erroneously proposed that the [[Radius (bone)|radius]] and [[ulna]] could cross, when in life they would have remained parallel.<ref name="gilmore36" /> ''Brontosaurus'' had a single large claw on each forelimb which faced towards the body, whereas the rest of the [[Phalanx bone|phalanges]] lacked [[ungual]]s.<ref name="martin06">{{cite book | title=Introduction to the Study of Dinosaurs (Second ed.) | publisher=Blackwell Publishing | last=Martin | first=A. J. | author-link=Anthony J. Martin | year=2006 | pages=560 |isbn=978-1-4051-3413-2| id= {{ASIN|1405134135|country=ca}} }}</ref> Even by 1936, it was recognized that no sauropod had more than one hand claw preserved, and this one claw is now accepted as the maximum number throughout the entire group.<ref name="gilmore36" /><ref name="upchurchmanus">{{cite journal | url=http://www.arca.museus.ul.pt/ArcaSite/obj/gaia/MNHNL-0000272-MG-DOC-web.PDF | title=Manus claw function in sauropod dinosaurs | last=Upchurch | first=P. | journal=Gaia | year=1994 | volume=10 | pages=161–171 | issn=0871-5424 | archive-date=October 9, 2022 | access-date=April 7, 2015 | archive-url=https://ghostarchive.org/archive/20221009/http://www.arca.museus.ul.pt/ArcaSite/obj/gaia/MNHNL-0000272-MG-DOC-web.PDF | url-status=live }}</ref> The metacarpals are elongated and thinner than the phalanges, bearing boxy articular ends on its proximal and distal faces.<ref name="Marsh" /> The single front claw bone is slightly curved and squarely shortened on the front end. The phalangeal formula is 2-1-1-1-1, meaning the innermost finger (phalanx) on the forelimb has two bones and the next has one. The single manual claw bone (ungual) is slightly curved and squarely truncated on the anterior end. Proportions of the manus bones vary within Apatosaurinae as well, with ''B. yahnahpin''<nowiki/>'s ratio of longest metacarpal to radius length around 0.40 or greater compared to a lower value in ''Apatosaurus louisae''.<ref name="TMB2015" /> The femora of ''Brontosaurus'' are very stout and represent some of the most robust femora of any member of Sauropoda. The [[tibia]] and [[fibula]] bones are different from the slender bones of ''Diplodocus'' but are nearly indistinguishable from those of ''Camarasaurus''. The fibula is longer and slenderer than the tibia. The foot of ''Brontosaurus'' has three claws on the innermost digits; the digit formula is 3-4-5-3-2. The first metatarsal is the stoutest, a feature shared among diplodocids.<ref name="gilmore36" /> ''B. excelsus''{{'}}s [[Talus bone|astragalus]] differs from other species in that it lacks a laterally directed ventral shelf.<ref name="TMB2015" />

==Classification==
''Brontosaurus'' is a member of the [[Family (biology)|family]] Diplodocidae, a [[cladistics|clade]] of gigantic sauropod [[dinosaur]]s. The family includes some of the longest and largest creatures ever to walk the earth, including ''Diplodocus'', ''[[Supersaurus]]'', and ''Barosaurus''. Diplodocids first evolved during the [[Middle Jurassic]] in what is now [[Georgia (country)|Georgia]], spreading to [[North America]] during the Late Jurassic.<ref>{{Cite journal |last1=Mannion |first1=Philip D. |last2=Upchurch |first2=Paul |last3=Mateus |first3=Octávio |last4=Barnes |first4=Rosie N. |last5=Jones |first5=Marc E. H. |date=2012 |title=New information on the anatomy and systematic position of Dinheirosaurus lourinhanensis (Sauropoda: Diplodocoidea) from the Late Jurassic of Portugal, with a review of European diplodocoids |url=http://www.tandfonline.com/doi/abs/10.1080/14772019.2011.595432 |journal=Journal of Systematic Palaeontology |language=en |volume=10 |issue=3 |pages=521–551 |doi=10.1080/14772019.2011.595432 |bibcode=2012JSPal..10..521M |s2cid=56468989 |issn=1477-2019|url-access=subscription }}</ref>  ''Brontosaurus'' is classified in the subfamily Apatosaurinae, which also includes ''Apatosaurus'' and possibly one or more unnamed genera.<ref name="TMB2015" /> Othniel Charles Marsh described ''Brontosaurus'' as being allied to ''Atlantosaurus'', within the now defunct group [[Atlantosauridae]].<ref name="riggs-1903" /><ref name="marsh1877">{{cite journal | url=http://marsh.dinodb.com/marsh/Marsh%201877%20-%20Notice%20of%20new%20dinosaurian%20reptiles%20from%20the%20Jurassic%20formation.pdf | title=Notice of New Dinosaurian Reptiles from the Jurassic formation | last=Marsh | first=O. C. | s2cid=130488291 | author-link=Othniel Charles Marsh | journal=American Journal of Science | date=December 1877 | volume=14 | issue=84 | pages=514–516 | bibcode=1877AmJS...14..514M | doi=10.2475/ajs.s3-14.84.514 | archive-date=July 2, 2021 | access-date=April 7, 2015 | archive-url=https://web.archive.org/web/20210702162916/http://marsh.dinodb.com/marsh/Marsh%201877%20-%20Notice%20of%20new%20dinosaurian%20reptiles%20from%20the%20Jurassic%20formation.pdf | url-status=dead }}</ref> In 1878, Marsh raised his family to the rank of suborder, including ''Apatosaurus'', ''Brontosaurus'', ''Atlantosaurus'', ''[[Camarasaurus|Morosaurus]]'' (=''Camarasaurus''), and ''Diplodocus''. He classified this group within Sauropoda. In 1903, Elmer S. Riggs mentioned that the name Sauropoda would be a junior synonym of earlier names, and grouped ''Apatosaurus'' within [[Opisthocoelia]].<ref name="riggs-1903">{{cite journal | url=http://www.miketaylor.org.uk/tmp/Riggs-1903_Structure%20and%20relationships%20of%20opisthocoelian%20dinosaurs.%20Part%20I.%20Apatosaurus%20Marsh.pdf | title=Structure and Relationships of Opisthocoelian Dinosaurs. Part I, ''Apatosaurus'' Marsh | last=Riggs | first=E. S. | author-link=Elmer S. Riggs | journal=Publications of the Field Columbian Museum Geographical Series | date=August 1903 | volume=2 | issue=4 | pages=165–196 | oclc=494478078 | archive-date=October 9, 2022 | access-date=April 7, 2015 | archive-url=https://ghostarchive.org/archive/20221009/http://www.miketaylor.org.uk/tmp/Riggs-1903_Structure%20and%20relationships%20of%20opisthocoelian%20dinosaurs.%20Part%20I.%20Apatosaurus%20Marsh.pdf | url-status=dead }}</ref> Most authors still use Sauropoda as the group name.<ref name="Upchurch05">{{cite journal | url=http://ci.nii.ac.jp/naid/110004665753/ | title=A new specimen of ''Apatosaurus ajax'' (Sauropoda: Diplodocidae) from the Morrison Formation (Upper Jurassic) of Wyoming, USA | last1=Upchurch | first1=P. | last2=Tomida | first2=Y. | last3=Barrett | first3=P. M. | journal=National Science Museum Monographs | year=2005 | volume=26 | issue=118 | pages=1–156 | issn=1342-9574 | archive-date=January 7, 2015 | access-date=April 7, 2015 | archive-url=https://web.archive.org/web/20150107075228/http://ci.nii.ac.jp/naid/110004665753 | url-status=live }}</ref>

Originally named by its discoverer Othniel Charles Marsh in 1879, ''Brontosaurus'' had long been considered a [[junior synonym]] of ''Apatosaurus''; its type species, ''Brontosaurus excelsus'', was reclassified as ''A. excelsus'' in 1903. However, an extensive study published in 2015 by a joint British-Portuguese research team concluded that ''Brontosaurus'' was a valid genus of sauropod distinct from ''Apatosaurus''.<ref name=TMB2015>{{Cite journal | doi = 10.7717/peerj.857| title = A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)| journal = PeerJ| volume = 3| pages = e857| year = 2015| last1 = Tschopp | first1 = E. | last2 = Mateus | first2 = O. V. | last3 = Benson | first3 = R. B. J. | pmid=25870766 | pmc=4393826| doi-access = free}}{{open access}}</ref><ref name="NYT-20150407">{{cite news |last=Gorman |first=James |title=A Prehistoric Giant Is Revived, if Only in Name |url=https://www.nytimes.com/2015/04/08/science/earth/the-brontosaurus-a-prehistoric-giant-is-revived-if-only-in-name.html |date=April 7, 2015 |work=[[The New York Times]] |access-date=April 7, 2015 |archive-date=May 1, 2019 |archive-url=https://web.archive.org/web/20190501093203/https://www.nytimes.com/2015/04/08/science/earth/the-brontosaurus-a-prehistoric-giant-is-revived-if-only-in-name.html |url-status=live }}</ref><ref>{{Cite web|url=https://www.scientificamerican.com/article/the-brontosaurus-is-back1/|title=The Brontosaurus Is Back|first=Charles|last=Choi|website=Scientific American|access-date=December 18, 2019|archive-date=September 2, 2019|archive-url=https://web.archive.org/web/20190902022430/https://www.scientificamerican.com/article/the-brontosaurus-is-back1/|url-status=live}}</ref> Nevertheless, not all paleontologists agree with this division.<ref name="d'emic 2015">D'Emic, M. 2015. [https://time.com/3810104/not-so-fast-brontosaurus/ "Not so fast, Brontosaurus"] {{Webarchive|url=https://web.archive.org/web/20201020180243/https://time.com/3810104/not-so-fast-brontosaurus/ |date=October 20, 2020 }}. Time.com</ref><ref name="prothero 2015"/> The same study classified two additional species that had once been considered ''Apatosaurus'' and ''Eobrontosaurus'' as ''Brontosaurus parvus'' and ''Brontosaurus yahnahpin'' respectively.<ref name=TMB2015/>

[[Cladogram]] of the Diplodocidae after Tschopp, [[Octávio Mateus|Mateus]], and Benson (2015):<ref name="TMB2015"/>
{{clade| style=font-size:85%;line-height:85%
|label1=[[Diplodocidae]]
|1={{clade
   |1=''[[Amphicoelias altus]]''
   |2={{clade
      |label1=[[Apatosaurinae]]
      |1={{clade
         |1=Unnamed species
         |2={{clade
            |1={{clade
               |1=''[[Apatosaurus ajax]]''
               |2=''[[Apatosaurus louisae]]'' }}
            |2={{clade
               |1='''''Brontosaurus excelsus'''''
               |2={{clade
                  |1='''''Brontosaurus yahnahpin'''''
                  |2='''''Brontosaurus parvus''''' }} }} }} }}
      |label2=[[Diplodocinae]]
      |2={{clade 
         |1=Unnamed species
         |2={{clade
            |1=''[[Tornieria africana]]''
            |2={{clade
               |1={{clade
                  |1=''[[Supersaurus lourinhanensis]]''
                  |2=''[[Supersaurus vivianae]]'' }}
               |2={{clade
                  |1=''[[Leinkupal laticauda]]''
                  |2={{clade
                     |1=''[[Galeamopus hayi]]''
                     |2={{clade
                        |1={{clade
                           |1=''[[Diplodocus carnegii]]''
                           |2=''[[Diplodocus hallorum]]'' }}
                        |2={{clade
                           |1=''[[Kaatedocus siberi]]''
                           |2=''[[Barosaurus lentus]]''
}} }} }} }} }} }} }} }} }} }}

===Species===
* '''''Brontosaurus excelsus''''', the type species of ''Brontosaurus'', was first named by Marsh in 1879. Many specimens have been assigned to the species, such as FMNH P25112, the skeleton mounted at the [[Field Museum of Natural History]], which has since been found to represent an unknown species of apatosaurine. ''Brontosaurus amplus'', is a junior synonym of ''B. excelsus''. ''B. excelsus'' therefore only includes its type specimen and the type specimen of ''B. amplus''.<ref name="TMB2015"/><ref name="Upchurch05"/> The largest of these specimens is estimated to have weighed up to 15 tonnes and measured up to {{convert|22|m|ft|abbr=on}} long from head to tail.<ref name=GSP10/> The known definitive ''B. excelsus'' fossils have been reported from Reed's Quarries 10 and 11 of the Morrison Formation Brushy Basin member in [[Albany County, Wyoming]], dated to the late Kimmeridgian age,<ref name="TMB2015"/><ref name="Macintosh" /> about 152 million years ago.
* '''''Brontosaurus parvus''''', first described as ''Elosaurus'' in 1902 by Peterson and Gilmore, was reassigned to ''Apatosaurus'' in 1994, and to ''Brontosaurus'' in 2015. Specimens assigned to this species include the holotype, CM 566 (a partial skeleton of a juvenile found in Sheep Creek Quarry 4 in Albany County, WY), BYU 1252-18531 (a nearly complete skeleton found in Utah and mounted at Brigham Young University), and the partial skeleton UW 15556. It dates to the middle Kimmeridgian.<ref name="Upchurch05" /> Adult specimens are estimated to have weighed up to 14 tonnes and measured up to {{convert|22|m|ft|abbr=on}} long from head to tail.<ref name="GSP10" />

* '''''Brontosaurus yahnahpin''''' is the oldest species, known from a single site from the lower Morrison Formation, Bertha Quarry, in Albany County, Wyoming, dating to about 155 million years ago.<ref name="foster2007">Foster, J. (2007). ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. 389pp.</ref><ref name=turner1999>Turner, C.E. and Peterson, F., (1999). "Biostratigraphy of dinosaurs in the Upper Jurassic Morrison Formation of the Western Interior, U.S.A." Pp. 77–114 in Gillette, D. D. (ed.), ''Vertebrate Paleontology in Utah''. Utah Geological Survey Miscellaneous Publication 99-1.</ref> It grew up to {{convert|21|m|ft|abbr=on}} long.<ref name="Holtz2008">Holtz, Thomas R. Jr. (2011) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'' [http://www.geol.umd.edu/~tholtz/dinoappendix/HoltzappendixWinter2010.pdf Winter 2010 Appendix.] {{Webarchive|url=https://web.archive.org/web/20110720090118/http://www.geol.umd.edu/~tholtz/dinoappendix/HoltzappendixWinter2010.pdf |date=July 20, 2011 }}</ref> It was described by James Filla and Patrick Redman in 1994 as a species of ''Apatosaurus'' (''A. yahnahpin'').<ref>Filla, J.A., Redman, P.D. (1994). "''Apatosaurus yahnahpin'': a preliminary description of a new species of diplodocid dinosaur from the Late Jurassic Morrison Formation of southern Wyoming, the first sauropod found with a complete set of "belly ribs"." ''Wyoming Geological Association, 44th Annual Field Conference Guidebook''. 159–178.</ref> The [[specific name (zoology)|specific name]] is derived from [[Lakota language|Lakota]] ''mah-koo yah-nah-pin'', "breast necklace", a reference to the pairs of sternal ribs that resemble the [[hair pipe]]s traditionally worn by the tribe. The holotype specimen is TATE-001, a relatively complete [[postcrania]]l skeleton found in the lower Morrison Formation of Wyoming. More fragmentary remains have also been referred to the species. A re-evaluation by Robert T. Bakker in 1998 found it to be more primitive, so Bakker coined the new generic name ''Eobrontosaurus'', derived from Greek {{transliteration|grc|eos}}, "dawn", and ''Brontosaurus''.<ref name="Bakker98" />

[[File:AMNH Apatosaurus.jpg|thumb|Skeleton of the AMNH apatosaurine (possibly ''B. excelsus'', specimen AMNH 460) as remounted in 1995]]
The cladogram below is the result of an analysis by Tschopp, Mateus, and Benson (2015). The authors analyzed most diplodocid type specimens separately to deduce which specimen belonged to which species and genus.<ref name="TMB2015"/>{{clade| style=font-size:85%; line-height:85%
|label1=[[Apatosaurinae]]
|1={{clade
 |1={{clade
   |1=YPM 1840 ("''Atlantosaurus''" ''[[Atlantosaurus immanis|immanis]]'' type)
   |2=NSMT-PV 20375 }}
 |2={{clade
  |1=AMNH 460
  |2={{clade
   |label1=''[[Apatosaurus]]''
   |1={{clade
    |label1=''Apatosaurus ajax''
    |1=YPM 1860 (''Apatosaurus ajax'' type)
    |label2=''Apatosaurus louisae''
    |2={{clade 
     |1=CM 3018 (''Apatosaurus louisae'' type)
     |2=YPM 1861 (''[[Apatosaurus laticollis]]'' type) }} }}
   |label2='''''Brontosaurus'''''
   |2={{clade
    |label1='''''Brontosaurus excelsus'''''
    |1={{clade
      |1=YPM 1980 (''Brontosaurus excelsus'' type)
      |2=YPM 1981 (''Brontosaurus amplus'' type) }}
    |2={{clade
     |1=AMNH 5764 (''[[Amphicoelias altus]]'' type)
     |2={{clade
       |1=FMNH P25112
       |2={{clade
         |label1='''''Brontosaurus yahnahpin'''''
         |1=Tate-001 (''Eobrontosaurus yahnahpin'' type)
         |label2='''''Brontosaurus parvus'''''
         |2={{clade
           |1=CM 566 (''Elosaurus parvus'' type)
           |2={{clade
             |1=UM 15556
             |2=BYU 1252-18531
}} }} }} }} }} }} }} }} }} }}

==Paleobiology==
[[File:Brontosaurus NT small.jpg|thumb|left|Restoration of a ''B. excelsus'' group]]
When ''Brontosaurus'' was described in 1879, the widespread notion in the scientific community was that sauropods were [[Semiaquatic|semi-aquatic]], lethargic reptiles that were inactive.<ref>Taylor, M.P. (2010). "Sauropod dinosaur research: a historical review". In Richard Moody, Eric Buffetaut, David M. Martill and Darren Naish (eds.), ''Dinosaurs (and other extinct saurians): a historical perspective''. HTML abstract.</ref><ref name="marsh1879" /><ref name="Marsh" /> In Othniel Marsh's publication ''The Dinosaurs of North America'', he described the dinosaur as "more or less amphibious, and its food was probably aquatic plants or other succulent vegetation".<ref name="Marsh" /> This is unsupported by fossil evidence. Instead, sauropods were active and had adaptations for dwelling on land.<ref name="taylor10" /> Marsh also noted the animal's supposed lack of intellect based on the small [[Neurocranium|braincase]] of the Felch Quarry skull and slender [[Nervous system|neural cord]]. Recent research has found signs of intelligence in dinosaurs, akin to modern birds, though sauropods had relatively small brains.<ref>Russell, Dale A. (1997). "Intelligence". In Kevin Padian; Philip J. Currie (eds.). ''Encyclopedia of dinosaurs''. San Diego: Academic Press. pp. 370–372. {{ISBN|978-0-12-226810-6}}.</ref>

Various uses for the single claw on the forelimb of sauropods have been proposed. One suggestion is that they were used for defense, but their shape and size make this unlikely. It was also possible they were for foraging, but the most probable use for the claw was grasping objects such as tree trunks when rearing.<ref name="upchurchmanus" />

Trackways of sauropods like ''Brontosaurus'' show that the average range for them was around {{convert|20|-|40|km|abbr=on|round=5|mi}} per day, and they could potentially reach a top speed of {{convert|20|-|30|km/h|abbr=on|mph}}.<ref>Fastovsky, D.E.; Weishampel, D.B. (2009). ''[https://web.archive.org/web/20150924004505/http://www.evolbiol.ru/large_files/dinosaurs2009.pdf Dinosaurs: A Concise Natural History]'' (PDF). Cambridge University Press. pp. 165–200. {{ISBN|978-0-521-88996-4}}. Archived from [http://www.evolbiol.ru/large_files/dinosaurs2009.pdf the original] (PDF) on September 24, 2015.</ref> The slow locomotion of sauropods may be due to the minimal muscling or recoil after strides.<ref name="sellers123">{{cite journal |last1=Sellers |first1=W. I. |last2=Margetts |first2=L. |last3=Coria |first3=R. A. |last4=Manning |first4=P. L. |year=2012 |title=March of the Titans: The Locomotor Capabilities of Sauropod Dinosaurs |journal=PLOS ONE |volume=8 |issue=10 |pages=e78733 |bibcode=2013PLoSO...878733S |doi=10.1371/journal.pone.0078733 |pmc=3864407 |pmid=24348896 |doi-access=free}}</ref> A possible bipedal trackway of a juvenile ''Apatosaurus'' is known, but it is disputed if it was possible for the sauropod.<ref>{{Cite web |last1=Magazine |first1=Smithsonian |last2=Black |first2=Riley |title=Did Wee Little Sauropods Stand Up to Run? |url=https://www.smithsonianmag.com/science-nature/did-wee-little-sauropods-stand-up-to-run-85531831/ |access-date=June 10, 2023 |website=Smithsonian Magazine |language=en}}</ref>

=== Diet and energy requirements ===
Being a diplodocid sauropod, ''Brontosaurus'' was herbivorous and fed on [[fern]]s, [[Bennettitales|cycadeoids]], [[Pteridospermatophyta|seed ferns]], and [[Equisetum|horsetails]], eating at ground height as a [[Browsing (herbivory)|nonselective browser]].<ref name=":0">{{Cite journal |last=Whitlock |first=John A. |date=April 6, 2011 |title=Inferences of Diplodocoid (Sauropoda: Dinosauria) Feeding Behavior from Snout Shape and Microwear Analyses |journal=PLOS ONE |language=en |volume=6 |issue=4 |pages=e18304 |doi=10.1371/journal.pone.0018304 |issn=1932-6203 |pmc=3071828 |pmid=21494685 |bibcode=2011PLoSO...618304W |doi-access=free }}</ref> The replacement method and physiology of ''Apatosaurus''{{'}}s teeth is unique, with the entire tooth row being replaced at once and up to 60% more often than ''Diplodocus''. The teeth of ''Apatosaurus'' are thick, lack denticles, and are strongly cylindrical in cross-section whereas they are long, slender, and elliptical in cross-section in ''Diplodocus''. These characteristics imply that ''Apatosaurus,'' and likely ''Brontosaurus'', consumed tougher vegetation than ''Diplodocus''.<ref name=":1" /> Diplodocids in general also have shorter necks than the long-necked, vertically inclined macronarians. This would result in [[niche partitioning]], the various taxa thus avoiding direct competition with each other due to feeding on different plants and at different heights.<ref>{{Cite journal |last1=Mannion |first1=Philip D. |last2=Tschopp |first2=Emanuel |last3=Whitlock |first3=John A. |date=2021 |title=Anatomy and systematics of the diplodocoid Amphicoelias altus supports high sauropod dinosaur diversity in the Upper Jurassic Morrison Formation of the USA |journal=Royal Society Open Science |language=en |volume=8 |issue=6 |pages=210377 |doi=10.1098/rsos.210377 |issn=2054-5703 |pmc=8206699 |pmid=34150318|bibcode=2021RSOS....810377M }}</ref> Hypotheses of the food requirements of ''Brontosaurus'' have been made, though predicting this is difficult due to the lack of modern analogues.<ref name="Gordon-2019">{{Citation |last1=Gordon |first1=Iain J. |title=The Ecology of Browsing and Grazing in Other Vertebrate Taxa |date=2019 |url=https://doi.org/10.1007/978-3-030-25865-8_15 |work=The Ecology of Browsing and Grazing II |pages=339–404 |editor-last=Gordon |editor-first=Iain J. |access-date=June 10, 2023 |series=Ecological Studies |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-25865-8_15 |isbn=978-3-030-25865-8 |last2=Prins |first2=Herbert H. T. |last3=Mallon |first3=Jordan |last4=Puk |first4=Laura D. |last5=Miranda |first5=Everton B. P. |last6=Starling-Manne |first6=Carolina |last7=van der Wal |first7=René |last8=Moore |first8=Ben |last9=Foley |first9=William |volume=239 |s2cid=210259098 |editor2-last=Prins |editor2-first=Herbert H. T.|url-access=subscription }}</ref> [[Endotherm]]s (mammals) and [[ectotherm]]s (reptiles) require a specific amount of [[nutrition]] to survive which correlates with their [[metabolism]] as well as body size. Estimations of the dietary necessities of ''Brontosaurus'' were made in 2010, with a guess of 2•10^4 to 50•10^4 [[Joule|kilojoules]] needed daily. This led to hypotheses on the distributions of ''Brontosaurus'' to meet this requirement, though they varied on whether it was an ectotherm or endotherm. If ''Brontosaurus'' was an endotherm, fewer adult individuals could be sustained than if it were an ectotherm, which could have tens of animals per square kilometer.<ref>Farlow JO, Coroian ID, Foster JR (2010) Giants on the landscape: modelling the abundance of megaherbivorous dinosaurs of the Morrison formation (late Jurassic, western USA). Hist Biol 22:403–429</ref><ref>Farlow JO (1976) A consideration of the trophic dynamics of a Late Cretaceous large-dinosaur community (Oldman formation). Ecology 57:841–857</ref> Due to this, it has been theorized that ''Brontosaurus'' and other sauropods living within the arid environment of the Morrison Formation participated in migrations between feeding sites.<ref name="Gordon-2019" /> James Farlow (1987) calculates that a ''Brontosaurus''-sized dinosaur about {{convert|35|t|LT ST|abbr=on}} would have possessed {{convert|5.7|t|LT ST|abbr=on}} of fermentation contents.<ref name="farlow87">{{cite journal | title=Speculations About the Diet and Physiology of Herbivorous Dinosaurs | last=Farlow | first=J.A. | journal=Paleobiology | jstor=2400838 | year=1987 | volume=13 | issue=1 | pages=60–72| doi=10.1017/S0094837300008587 | s2cid=88396062 }}</ref> Assuming ''Apatosaurus'' had an avian respiratory system and a reptilian resting-metabolism, Frank Paladino ''et{{nbsp}}al''. (1997) estimate the animal would have needed to consume only about {{convert|262|L|sp=us}} of water per day.<ref name="Paladino">{{Cite book |last1=Paladino |first1=F.V. |title=The Complete Dinosaur |last2=Spotila |first2=J.R. |last3=Dodson |first3=P. |publisher=Indiana University Press |year=1997 |isbn=978-0-253-33349-0 |editor-last=Farlow |editor-first=J.O. |pages=491–504 |chapter=A Blueprint for Giants: Modeling the Physiology of Large Dinosaurs |editor-last2=Brett-Surman |editor-first2=M.K.}}</ref>

===Posture===
{{further|Sauropod neck posture}}

[[File:Brontosaurus parvus.jpg|left|thumb|Cast of ''B. parvus'' specimen UWGM 15556 at [[Tellus Science Museum]]]]
Historically, sauropods like ''Brontosaurus'' were believed to have been too massive to support their weight on dry land, so theoretically, they must have lived partly submerged in water, perhaps in swamps. Recent findings do not support this, and sauropods are thought to have been fully terrestrial animals.<ref name="Pierson">{{cite journal | pmid=19558740 | title=The Physiology of Dinosaurs: Circulatory and Respiratory Function in the Largest Animals Ever to Walk the Earth | last=Pierson | first=D. J. | journal=Respiratory Care | year=2009 | volume=54 | issue=7 | pages=887–911 | doi=10.4187/002013209793800286| doi-broken-date=November 14, 2024 }}</ref> Diplodocids like ''Brontosaurus'' are often portrayed with their necks held high up in the air, allowing them to browse on tall trees. Though some studies have suggested that diplodocid necks were less flexible than previously believed,<ref name="StevensParrish99">{{cite journal | url=http://www.sciencemag.org/cgi/content/abstract/284/5415/798 | title=Neck Posture and Feeding Habits of Two Jurassic Sauropod Dinosaurs | access-date=August 3, 2008 | last1=Stevens | first1=Kent A. | last2=Parrish | first2=J. M. | journal=Science | year=1999 | volume=284 | issue=5415 | pages=798–800 | doi=10.1126/science.284.5415.798 | pmid=10221910 | bibcode=1999Sci...284..798S | url-access=subscription | archive-date=February 27, 2009 | archive-url=https://web.archive.org/web/20090227102305/http://www.sciencemag.org/cgi/content/abstract/284/5415/798 | url-status=live }}</ref> other studies have found that all [[tetrapod]]s appear to hold their necks at the maximum possible vertical extension when in a normal, alert posture, and argue that the same would hold true for sauropods barring any unknown, unique characteristics that set the soft tissue anatomy of their necks apart from that of other animals.<ref name="taylor14">{{Cite journal |last1=Taylor |first1=M. P. |date=2014 |title=Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs |journal=PeerJ |volume=2 |pages=e712 |doi=10.7717/peerj.712 |pmc=4277489 |pmid=25551027 |doi-access=free }}</ref>

===Physiology===
{{further|Physiology of dinosaurs}}

[[File:Apatosaurus caudal vertebra pneumatic fossa.png|upright|thumb|Pneumatic fossa in a caudal vertebra of the ''B. excelsus'' holotype]]
James Spotila ''et al''. (1991) suggest that the large body size of ''Brontosaurus'' and other sauropods would have made them unable to maintain high metabolic rates, as they would not be able to release enough heat. However, temperatures in the Jurassic were 3 degrees Celsius higher than present.<ref name="spotila91">{{cite journal | title=Hot and cold running dinosaurs. Metabolism, body temperature, and migration |author1=Spotila, J. R. |author2=O'Connor, M. P. |author3=Dodson, P. R. |author4=Paladino, F. V. | journal=Modern Geology | year=1991 | volume=16 | pages=203–227}}</ref> Furthermore, they assumed that the animals had a reptilian respiratory system. Matt Wedel found that an avian system would have allowed them to dump more heat.<ref name="Wedel 2003">{{cite journal | title=Vertebral Pneumaticity, Air Sacs, and the Physiology of Sauropod Dinosaurs | author=Wedel, M. J. | journal=Paleobiology | jstor=4096832 | year=2003 | volume=29 | issue=2 | pages=243–255 | doi=10.1666/0094-8373(2003)029<0243:vpasat>2.0.co;2 | bibcode=2003Pbio...29..243W | s2cid=46619244 | url=http://doc.rero.ch/record/14872/files/PAL_E2010.pdf | archive-date=May 18, 2023 | access-date=January 4, 2023 | archive-url=https://web.archive.org/web/20230518003816/https://doc.rero.ch/record/14872/files/PAL_E2010.pdf | url-status=live }}</ref> Some scientists have also argued that the heart would have had trouble sustaining sufficient blood pressure to oxygenate the brain.<ref name="Pierson"/>

Given the large body mass and long neck of sauropods like ''Brontosaurus'', physiologists have encountered problems determining how these animals breathed. Beginning with the assumption that, like [[crocodilia]]ns, ''Brontosaurus'' did not have a [[Thoracic diaphragm|diaphragm]], the [[Dead space (physiology)|dead-space volume]] (the amount of unused air remaining in the mouth, trachea, and air tubes after each breath) has been estimated at {{convert|184|L|m3|abbr=on|order=flip}} for a {{convert|30|t|LT ST|abbr=on}} specimen. Paladino calculates its [[Lung volumes|tidal volume]] (the amount of air moved in or out during a single breath) at {{convert|904|L|m3|abbr=on|order=flip}} with an avian respiratory system, {{convert|225|L|m3|abbr=on|order=flip}} if mammalian, and {{convert|19|L|m3|abbr=on|order=flip}} if reptilian.<ref name="Paladino" />

Based on this, its respiratory system would likely have consisted of [[parabronchi]], with multiple pulmonary air sacs as in [[avian lungs]], and a flow-through lung. An avian respiratory system would need a lung volume of about {{convert|600|L|m3|abbr=on|order=flip}} compared with a mammalian requirement of {{convert|2,950|L|m3|abbr=on|order=flip}}, which would exceed the space available. The overall thoracic volume of the same-sized ''Apatosaurus'' has been estimated at {{convert|1,700|L|m3|abbr=on|order=flip}}, allowing for a {{convert|500|L|m3|abbr=on|order=flip}}, four-chambered heart and a {{convert|900|L|m3|abbr=on|order=flip}} lung capacity. That would allow about {{convert|300|L|m3|abbr=on|order=flip}} for the necessary tissue.<ref name="Paladino" /> Evidence for the avian system in ''Brontosaurus'' and other sauropods is also present in the pneumaticity of the vertebrae. Though this plays a role in reducing the weight of the animal, Wedel (2003) states they are also likely connected to air sacs, as in birds.<ref name="Wedel 2003" />

===Juveniles===
[[File:Apatosaurus louisae juvenile sauropod dinosaur (Morrison Formation, Upper Jurassic; Sheep Creek, Albany County, southeastern Wyoming, USA).jpg|thumb|Reconstructed skeleton of a juvenile ''B. parvus'' (type specimen CM 566), [[Carnegie Museum of Natural History]]]]

A 1999 microscopic study of ''Apatosaurus'' and ''Brontosaurus'' bones concluded the animals grew rapidly when young and reached near-adult sizes in about 10{{nbsp}}years.<ref name="Curry99">{{cite journal | title=Ontogenetic histology of Apatosaurus (Dinosauria: Sauropoda): new insights on growth rates and longevity | last=Curry | first=Kristina A. | authorlink=Kristina Curry Rogers | journal=Journal of Vertebrate Paleontology | jstor=4524036 | year=1999 | volume=19 | issue=4 | pages=654–665 | doi=10.1080/02724634.1999.10011179| bibcode=1999JVPal..19..654C }}</ref><ref>{{cite journal|last1=Jack R.|first1=Horner|year=2005|title=How Dinosaurs Grew So Large—And So Small|journal=Scientific American|volume=293 |issue=1 |page=56 |bibcode=2005SciAm.293a..56H |url=https://www.eoas.ubc.ca/~mjelline/212_website/212_live/Reading_2021/Group-1_Horner_2017_how_dinosaurs_grew_large.pdf}}</ref> In 2008, a study on the growth rates of sauropods was published by biologists Thomas Lehman and [[Holly Woodward]]. They said that by using growth lines and length-to-mass ratios, ''Apatosaurus'' would have grown to 25{{nbsp}}t (25 long tons; 28 short tons) in 15{{nbsp}}years, with growth peaking at {{convert|5000|kg|-2|abbr=on}} in a single year. An alternative method, using limb length and body mass, found ''Brontosaurus'' and ''Apatosaurus'' grew {{convert|520|kg|lb|abbr=on}} per year, and reached their full mass before it was about 70{{nbsp}}years old.<ref name="lehman&woodward">{{cite journal | title=Modelling growth rates for sauropod dinosaurs | last1=Lehman | first1=T.M. | last2=Woodward | first2=H.N. | journal=Paleobiology | year=2008 | volume=34 | issue=2 | pages=264–281 | doi=10.1666/0094-8373(2008)034[0264:MGRFSD]2.0.CO;2 | s2cid=84163725 | url=http://doc.rero.ch/record/16723/files/PAL_E3766.pdf | archive-date=February 4, 2023 | access-date=June 11, 2023 | archive-url=https://web.archive.org/web/20230204092325/https://doc.rero.ch/record/16723/files/PAL_E3766.pdf | url-status=live }}</ref> These estimates have been called unreliable because the calculation methods are not sound; old growth lines would have been obliterated by bone remodeling.<ref name="griebeler">{{cite journal | first1=EM | first2=N | first3=PM | journal=PLOS ONE | issue=6 | doi=10.1371/journal.pone.0067012 | last1=Griebeler | title=Aging, Maturation and Growth of Sauropodomorph Dinosaurs as Deduced from Growth Curves Using Long Bone Histological Data: An Assessment of Methodological Constraints and Solutions | last2=Klein | last3=Sander | year=2013 | volume=8 | page=e67012 | pmid=23840575 | pmc=3686781 | bibcode=2013PLoSO...867012G | doi-access=free }}</ref> One of the first identified growth factors of ''Apatosaurus'' was the number of sacral vertebrae, which increased to five by the time of the creature's maturity. This was first noted in 1903 and again in 1936.<ref name="gilmore36" /><ref name="riggs-1903" />

Juvenile ''Brontosaurus'' material is known based on the type specimen of ''B. parvus''. The material of this specimen, CM 566, includes vertebrae from various regions, one pelvic bone, and some bones of the hindlimb.<ref name="Upchurch05"/> When describing ''B. parvus,'' Peterson and Gilmore noted that the neural spines were sutured, the sacral vertebrae were unfused, and the coracoid was missing. All of these features are signs of immaturity in other archosaurs, showing that sauropods had these traits too.<ref name="Peterson-1902" /> Peterson and Gilmore also theorized that sauropods never stopped growing, which supposedly helped in attaining their massive size, a concept unsupported by fossils.<ref>{{Cite journal |last1=Griebeler |first1=Eva Maria |last2=Klein |first2=Nicole |last3=Sander |first3=P. Martin |date=June 19, 2013 |title=Aging, Maturation and Growth of Sauropodomorph Dinosaurs as Deduced from Growth Curves Using Long Bone Histological Data: An Assessment of Methodological Constraints and Solutions |journal=PLOS ONE |language=en |volume=8 |issue=6 |pages=e67012 |doi=10.1371/journal.pone.0067012 |issn=1932-6203 |pmc=3686781 |pmid=23840575 |bibcode=2013PLoSO...867012G |doi-access=free }}</ref>

===Tail===
The estimated tail length of ''Brontosaurus'' is approximately 56% of the total body length, with the tail sometimes hypothesized to be capable of functioning like a very long, tapering [[bullwhip]].<ref name=Baron/> An article that appeared in the November 1997 issue of [[Discover (magazine)|''Discover'' magazine]] reported research into the mechanics of diplodocid tails by [[Nathan Myhrvold]], a [[computer scientist]] from [[Microsoft]]. Myhrvold carried out a [[computer simulation]] of the tail, which in diplodocids like ''Brontosaurus'' was a very long, tapering structure resembling a [[bullwhip]]. This computer modeling suggested that sauropods were capable of producing a whip-like cracking sound of over 200 [[decibel]]s, comparable to the volume of a [[cannon]].<ref name="zimmer1997">{{cite magazine | url=http://discovermagazine.com/1997/nov/dinosaursinmotio1261 | magazine=[[Discover (magazine)|Discover]] | title=Dinosaurs in Motion | date=November 1997 | access-date=July 27, 2008 | last=Zimmer | first=C. | archive-date=September 22, 2008 | archive-url=https://web.archive.org/web/20080922122640/http://discovermagazine.com/1997/nov/dinosaursinmotio1261/ | url-status=live }}</ref> There is some circumstantial evidence supporting this as well: a number of diplodocids have been found with fused or damaged tail vertebrae, which may be a symptom of cracking their tails: these are particularly common between the 18th and the 25th caudal vertebra, a region the authors consider a transitional zone between the stiff muscular base and the flexible whiplike section.<ref>{{Cite journal |last1=Myhrvold |first1=Nathan P. |last2=Currie |first2=Philip J. |date=1997 |title=Supersonic sauropods? Tail dynamics in the diplodocids |url=https://www.cambridge.org/core/journals/paleobiology/article/abs/supersonic-sauropods-tail-dynamics-in-the-diplodocids/2F49D4918CABD1009D5D4DA5B6F67287 |journal=Paleobiology |language=en |volume=23 |issue=4 |pages=393–409 |doi=10.1017/S0094837300019801 |bibcode=1997Pbio...23..393M |s2cid=83696153 |issn=0094-8373 |url-access=subscription |archive-date=February 4, 2021 |access-date=April 19, 2022 |archive-url=https://web.archive.org/web/20210204050838/https://www.cambridge.org/core/journals/paleobiology/article/abs/supersonic-sauropods-tail-dynamics-in-the-diplodocids/2F49D4918CABD1009D5D4DA5B6F67287 |url-status=live }}</ref> However, Rega (2012) notes that ''Camarasaurus'' while lacking a tailwhip, displays a similar level of caudal co-ossification and that ''[[Mamenchisaurus]]'' while having the same pattern of vertebral metrics, lacks a tailwhip and does not display fusion in any "transitional region". Also, the crush fractures which would be expected if the tail was used as a whip have never been found in diplodocids.<ref>{{Cite book |title=Rega, E. (2012). "Disease in Dinosaurs". In Brett-Surman, M.; Holtz, T.; Farlow, J. (eds.). The Complete Dinosaur. Bloomington: Indiana University Press.}}</ref> More recently, Baron (2020) has considered the use of the tail as a bullwhip unlikely because of the potentially catastrophic muscle and skeletal damage such speeds could cause on the large and heavy tail. Instead, he proposes that the tails might have been used as a tactile organ to keep in touch with the individuals behind and to the sides of the animal in a group, which could have augmented cohesion and allowed communication among individuals while limiting more energetically demanding activities like stopping to search for dispersed individuals, turning to visually check on others behind, or communicating vocally.<ref name=Baron>{{Cite journal |last=Baron |first=Matthew G. |date=October 3, 2021 |title=Tactile tails: a new hypothesis for the function of the elongate tails of diplodocid sauropods |url=https://doi.org/10.1080/08912963.2020.1769092 |journal=Historical Biology |volume=33 |issue=10 |pages=2057–2066 |doi=10.1080/08912963.2020.1769092 |bibcode=2021HBio...33.2057B |s2cid=219762797 |issn=0891-2963 |url-access=subscription |archive-date=May 29, 2020 |access-date=April 19, 2022 |archive-url=https://web.archive.org/web/20200529191808/https://www.tandfonline.com/doi/full/10.1080/08912963.2020.1769092 |url-status=live }}</ref>

=== Neck combat ===

[[File:Brontosaurus excelsus Cv8 Marsh 1881.jpg|alt=Cervical vertebra of Brontosaurus excelsus.|thumb|right|A [[Cervical vertebrae|cervical vertebra]] of ''B. excelsus'', showing its robusticity]]

The cervical vertebrae of ''Brontosaurus'' and ''Apatosaurus'' are robust, which has led to speculation on the use of these structures. These structures had expensive energy requirements, so the reason for their evolution must have been important to the animal. Notable features include dense cervical ribs and diapophyses, ribs that are angled ventrally, and an overall subtriangular cross-section. These traits are in contrast to the more fragile cervicals of diplodocines.<ref>{{Cite journal |last1=Klein |first1=Nicole |last2=Christian |first2=Andreas |last3=Sander |first3=P. Martin |date=December 23, 2012 |title=Histology shows that elongated neck ribs in sauropod dinosaurs are ossified tendons |journal=Biology Letters |language=en |volume=8 |issue=6 |pages=1032–1035 |doi=10.1098/rsbl.2012.0778 |issn=1744-9561 |pmc=3497149 |pmid=23034173}}</ref> Cervical ribs acted as anchors for the [[Longus colli muscle|longus colli ventralis]] and [[Anatomical terminology|flexer colli lateralis]] muscles, which are used in the downward motion of the neck. Stronger muscles for ventral motions allowed more force to be exerted downward. The cervical ribs formed a "V"-shape, which could be used to shelter the softer underlying tissues of the neck from damage. Ventral sides of the cervical ribs were capped by round, protruding [[Process (anatomy)|processes]]. These have been suggested to have been attachment points for [[Boss (engineering)|bosses]] or [[keratin]]ous spikes. A [[preprint]] by Wedel ''et al'' (2015) thought that due to the combination of these traits, ''Brontosaurus'' would use its neck for combat between individuals through the use of striking necks.<ref name="twne15" /><ref>{{Cite web |date=September 14, 2015 |title=So what were apatosaurs doing with their crazy necks? |url=https://svpow.com/2015/09/14/so-what-were-apatosaurs-doing-with-their-crazy-necks/ |access-date=June 17, 2023 |website=Sauropod Vertebra Picture of the Week |language=en |archive-date=June 17, 2023 |archive-url=https://web.archive.org/web/20230617163825/https://svpow.com/2015/09/14/so-what-were-apatosaurs-doing-with-their-crazy-necks/ |url-status=live }}</ref> Behavior like this has been observed in other animals like giraffes and large tortoises.<ref>Hone, D. W. E., & Naish, D. (2013). The ‘species recognition hypothesis’ does not explain the presence and evolution of exaggerated structures in non-avialan dinosaurs. ''Journal of Zoology'' '''290(3)''':172-180.</ref><ref>{{Cite journal |last1=Simmons |first1=Robert E. |last2=Scheepers |first2=Lue |date=1996 |title=Winning by a Neck: Sexual Selection in the Evolution of Giraffe |url=https://www.jstor.org/stable/2463405 |journal=The American Naturalist |volume=148 |issue=5 |pages=771–786 |doi=10.1086/285955 |jstor=2463405 |bibcode=1996ANat..148..771S |s2cid=84406669 |issn=0003-0147 |url-access=subscription |archive-date=November 16, 2020 |access-date=June 17, 2023 |archive-url=https://web.archive.org/web/20201116161729/https://www.jstor.org/stable/2463405 |url-status=live }}</ref>

== Paleoecology ==

[[File:AMNH Allosaurus.jpg|thumb|left|''[[Allosaurus]]'' mounted as if feeding on a ''Brontosaurus'' carcass, AMNH]]
The Morrison Formation is a sequence of shallow marine and alluvial sediments which, according to [[radiometric dating]], ranges between 156.3 million years old (Mya) at its base,<ref name="TCR06">{{cite journal | title=Oxfordian U/Pb ages from SHRIMP analysis for the Upper Jurassic Morrison Formation of southeastern Wyoming with implications for biostratigraphic correlations | last=Trujillo | first=K. C. | author2=Chamberlain, K. R. | author3=Strickland, A. | journal=Geological Society of America Abstracts with Programs | year=2006 | volume=38 | issue=6 | pages=7}}</ref> and 146.8 Mya at the top,<ref name="SAB98">{{cite book | chapter=Cleveland-Lloyd Dinosaur Quarry – age, stratigraphy and depositional environments | editor=Carpenter, K. |editor2=Chure, D. |editor3=Kirkland, J. I. | title=The Morrison Formation: An Interdisciplinary Study | publisher=Taylor and Francis Group | last=Bilbey | first=S. A. | series=Modern Geology 22 | year=1998 | pages=87–120 | issn=0026-7775}}</ref> which places it in the late [[Oxfordian stage|Oxfordian]], Kimmeridgian, and early Tithonian [[faunal stages|stages]] of the Late Jurassic period. This formation is interpreted as a [[semi-arid]] environment with distinct [[wet season|wet]] and [[dry season]]s. The Morrison Basin, where dinosaurs lived, stretched from New Mexico to Alberta and Saskatchewan and was formed when the precursors to the [[Front Range]] of the Rocky Mountains started pushing up to the west. The deposits from their east-facing [[drainage basin]]s were carried by streams and [[river]]s and deposited in [[swamp]]y lowlands, lakes, river channels, and [[floodplain]]s.<ref name="DAR89">{{cite book | title=An Odyssey in Time: Dinosaurs of North America | publisher=NorthWord Press | last=Russell | first=Dale A. | author-link=Dale Russell | year=1989 | location=Minocqua, Wisconsin | pages=64–70 |isbn=978-1-55971-038-1}}</ref> This formation is similar in age to the [[Lourinha Formation|Lourinhã Formation]] in [[Portugal]] and the [[Tendaguru Formation]] in [[Tanzania]].<ref name="OM06">{{cite book | chapter=Jurassic dinosaurs from the Morrison Formation (USA), the Lourinhã and Alcobaça Formations (Portugal), and the Tendaguru Beds (Tanzania): A comparison | title=Paleontology and Geology of the Upper Jurassic Morrison Formation | publisher=New Mexico Museum of Natural History and Science | last=Mateus | first=Octávio | editor=Foster, John R. |editor2=Lucas, Spencer G. | series=New Mexico Museum of Natural History and Science Bulletin, '''36''' | year=2006 | location=Albuquerque, New Mexico | pages=223–231}}</ref>

''Brontosaurus'' may have been a more solitary animal than other Morrison Formation dinosaurs.<ref name="DBBM80">{{cite journal | title=Taphonomy and paleoecology of the dinosaur beds of the Jurassic Morrison Formation | last=Dodson | first=Peter | author2=Behrensmeyer, A.K. | author3=Bakker, Robert T. | author4=McIntosh, John S. | journal=Paleobiology | year=1980 | volume=6 | issue=2 | pages=208–232| doi=10.1017/S009483730000676X | bibcode=1980Pbio....6..208D | s2cid=130686856 }}</ref> As a genus, ''Brontosaurus'' existed for a long interval, and was found in most levels of the Morrison. ''B. excelsus'' fossils have been reported from only the Brushy Basin Member, dating to the late Kimmeridgian age, about 151 Mya.<ref name="turner1999"/> Older ''Brontosaurus'' remains have also been identified from the middle Kimmeridgian, and are assigned to ''B. parvus''.<ref name="Upchurch05"/> Fossils of these animals have been found in [[Nine Mile Quarry]] and [[Bone Cabin Quarry]] in Wyoming and at sites in Colorado, Oklahoma, and Utah, present in stratigraphic zones 2–6 according to John Foster’s model.<ref name="foster-2007"/>

The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs.<ref name="foster-2007">{{cite book | title=Jurassic West: The Dinosaurs of the Morrison Formation and Their World | publisher=Indiana University Press | last=Foster | first=John | year=2007 | pages=273–329 |isbn=978-0-253-34870-8}}</ref> Dinosaurs known from the Morrison include the theropods ''[[Ceratosaurus]]'', ''[[Ornitholestes]]'', and ''[[Allosaurus]]'', the sauropods ''Apatosaurus'', ''Brachiosaurus'', ''Camarasaurus'', and ''Diplodocus'', and the [[ornithischia]]ns ''[[Camptosaurus]]'', ''[[Dryosaurus]]'', and ''[[Stegosaurus]]''.<ref name="DJCetal06">{{cite book | title=Paleontology and Geology of the Upper Jurassic Morrison Formation | publisher=New Mexico Museum of Natural History and Science | last=Chure | first=Daniel J. | editor=Foster, John R. |editor2=Lucas, Spencer G. | author2=Litwin, Ron | author3=Hasiotis, Stephen T. | author4=Evanoff, Emmett | author5=Carpenter, Kenneth | chapter=The fauna and flora of the Morrison Formation: 2006 | series=New Mexico Museum of Natural History and Science Bulletin, 36 | year=2006 | location=Albuquerque, New Mexico | pages=233–248}}</ref> Other vertebrates that shared this paleoenvironment included [[actinopterygii|ray-finned fishes]], [[frog]]s, [[salamander]]s, [[turtle]]s, [[sphenodontia|sphenodonts]], [[lizard]]s, terrestrial and aquatic [[crocodylomorpha|crocodylomorphs]], and several species of [[pterosaur]]s. Shells of [[bivalve]]s and aquatic [[snail]]s, are also common. The flora of the period has been revealed by fossils of [[chlorophyta|green algae]], [[moss]]es, [[equisetum|horsetails]], [[cycad]]s, [[ginkgo]]es, and several families of [[conifer]]s. Vegetation varied from river-lining forests of [[tree fern]]s and ferns ([[gallery forest]]s), to fern [[savanna]]s with occasional trees such as the ''[[Araucaria]]''-like conifer ''[[Brachyphyllum]]''.<ref name="KC06">{{cite book | chapter=Biggest of the big: a critical re-evaluation of the mega-sauropod ''Amphicoelias fragillimus'' | editor=Foster, John R. |editor2=Lucas, Spencer G. | title=Paleontology and Geology of the Upper Jurassic Morrison Formation | publisher=New Mexico Museum of Natural History and Science | last=Carpenter | first=Kenneth | author-link=Kenneth Carpenter | series=New Mexico Museum of Natural History and Science Bulletin, '''36''' | year=2006 | location=Albuquerque, New Mexico | pages=131–138}}</ref>

==In popular culture==
[[File:Pasta-Brontosaurus.jpg|thumb|Outdated 1897 restoration by [[Charles R. Knight]] of ''B. excelsus'' submerged in water, and ''Diplodocus'' dragging its tail]]

The length of time taken for Riggs's 1903 reclassification of ''Brontosaurus'' as ''Apatosaurus'' to be brought to public notice, as well as Osborn's insistence that the ''Brontosaurus'' name be retained despite Riggs's paper, meant that ''Brontosaurus'' became one of the most famous dinosaurs. ''Brontosaurus'' has often been depicted in cinema, beginning with [[Winsor McCay]]'s 1914 classic ''[[Gertie the Dinosaur]]'', one of the first animated films.<ref name="crafton82">{{cite book | title=Before Mickey: The Animated Film 1898–1928 | publisher=MIT Press | author=Donald Crafton | year=1982 |isbn=978-0-262-03083-0}}</ref> McCay based his unidentified dinosaur on the apatosaurine skeleton in the American Museum of Natural History.<ref name="dinoparade">{{cite web | url=http://www.sdnhm.org/exhibits/dinosrr/index.html | title=Dinos Parade across the Silver Screen | publisher=[[San Diego Natural History Museum]] | archive-url=https://web.archive.org/web/20111011090258/http://www.sdnhm.org/exhibits/dinosrr/index.html | archive-date=October 11, 2011}}</ref> The 1925 silent film ''[[The Lost World (1925 film)|The Lost World]]'' featured a battle between a ''Brontosaurus'' and an ''Allosaurus'', using [[special effect]]s by [[Willis O'Brien]].<ref name="glut97">{{cite book | chapter=Dinosaurs and the media | editor1-first=James | editor1-last=Farlow | editor2-first=Michael K. | editor2-last=Brett-Surman | first1=Donald F. | first2=Michael K. | last1=Glut | title=The Complete Dinosaur | publisher=Indiana University Press | last2=Brett-Surman | year=1997 | location=Bloomington and Indianapolis | pages=[https://archive.org/details/isbn_9780253333490/page/675 675–706] |isbn=978-0-253-33349-0 | url-access=registration | url=https://archive.org/details/isbn_9780253333490/page/675 }}</ref> The 1933 film ''[[King Kong (1933 film)|King Kong]]'' featured a ''Brontosaurus'' chasing Carl Denham, Jack Driscoll and the terrified sailors on Skull Island. In 1938 the assembling of a ''Brontosaurus'' skeleton was a major plot point in the [[Katharine Hepburn]] and [[Cary Grant]] film ''[[Bringing Up Baby]]''. These, and other early uses of the animal as a major representative of the group, helped cement ''Brontosaurus'' as a quintessential dinosaur in the public consciousness.<ref name="gould1991">{{cite book | title=Bully for Brontosaurus: Reflections in Natural History | url=https://archive.org/details/bullyforbrontosa00step | url-access=registration | publisher=W. W. Norton & Co. | date=1991 | last=Gould | first=S. J. | author-link=Stephen Jay Gould | pages=540}}</ref>

[[Sinclair Oil Corporation]] has long been a fixture of American roads (and briefly in other countries) with its green dinosaur logo and mascot, a ''Brontosaurus''. While Sinclair's early advertising included a number of different dinosaurs, eventually only ''Brontosaurus'' was used as the official logo, due to its popular appeal.<ref name="sinclairoil">{{cite web | url=http://www.sinclairoil.com/history/symbol_01.html | title=Evolution of the Company Symbol | publisher=Sinclair Oil Corporation | date=2013 | access-date=April 8, 2014 | archive-date=June 21, 2014 | archive-url=https://web.archive.org/web/20140621113403/http://www.sinclairoil.com/history/symbol_01.html | url-status=dead }}</ref>
[[File:Winsor McCay (1914)Gertie the Dinosaur.webm|thumb|left|alt=Animated film of a trained dinosaur.|thumbtime=16:46|''Gertie the Dinosaur'' (1914)]]

As late as 1989, the [[United States Postal Service|U.S. Postal Service]] faced controversy when it issued four "dinosaur" stamps: ''[[Tyrannosaurus]]'', ''Stegosaurus'', ''[[Pteranodon]]'', and ''Brontosaurus''. The use of the term ''Brontosaurus'' in place of ''Apatosaurus'' led to complaints of "fostering scientific illiteracy."<ref name="NYT">{{cite news | url=https://www.nytimes.com/1989/10/11/opinion/topics-of-the-times-leapin-lizards.html | title=Topics of The Times: Leapin' Lizards! | date=October 11, 1989 | access-date=June 8, 2008 | newspaper=[[The New York Times]] | archive-date=May 28, 2009 | archive-url=https://web.archive.org/web/20090528011614/http://www.nytimes.com/1989/10/11/opinion/topics-of-the-times-leapin-lizards.html | url-status=live }}</ref> The Postal Service defended itself (in Postal Bulletin 21742)<ref>{{Cite report|url=http://www.uspostalbulletins.com/PDF/Vol110_Issue21742_19890914.pdf |title=Postal Bulletin |date=September 14, 1989 |publisher=United States Postal Service |issue=PB 21742 |location=Washington, DC |page=7 |access-date=October 6, 2023}}</ref> by saying, "Although now recognized by the scientific community as ''Apatosaurus'', the name ''Brontosaurus'' was used for the stamp because it is more familiar to the general population." Indeed, the Postal Service even implicitly rebuked the somewhat inconsistent complaints by adding that "[s]imilarly, the term 'dinosaur' has been used generically to describe all the animals [i.e., all four of the animals represented in the given stamp set], even though the ''Pteranodon'' was a flying reptile [rather than a true 'dinosaur']," a distinction left unmentioned in the numerous correspondence regarding the ''Brontosaurus''/''Apatosaurus'' issue.<ref>{{Cite web |title=25c Brontosaurus (Apatosaurus) single |url=https://postalmuseum.si.edu/object/npm_1990.0517.12903 |access-date=October 6, 2023 |website=Smithsonian National Postal Museum |language=en}}</ref> Palaeontologist [[Stephen Jay Gould]] supported this position. In the essay from which the title of the 1991 collection ''[[Bully for Brontosaurus]]'' is taken, Gould wrote: "Touché and right on; no one bitched about ''Pteranodon'', and that's a real error."<ref name="gould1991" /> His position, however, was not one suggesting the exclusive use of the popular name; he echoed Riggs' original argument that ''Brontosaurus'' is a synonym for ''Apatosaurus''. Nevertheless, he noted that the former has developed and continues to maintain an independent existence in the popular imagination.<ref name="gould1991"/>

The more vociferous denunciations of the usage have elicited sharply defensive statements from those who would not wish to see the name be struck from official usage.<ref name="gould1991" /> Tschopp's study<ref name="TMB2015" /> has generated a very high number of responses from many, often opposed, {{nowrap|groups{{tsp}}{{mdash}}{{tsp}}}}of editorial,<ref>{{Cite news|title = Dino-Mite! Study Suggests That the Brontosaurus Really Did Exist.|url = http://www.slate.com/blogs/the_slatest/2015/04/07/brontosaurus_is_back_a_new_study_could_revive_a_popular_dinosaur_genus.html|journal = Slate|date = April 7, 2015|access-date = June 18, 2015|issn = 1091-2339|first = Rachael|last = Larimore}}</ref> news staff,<ref name="NYT-20150407" /><ref>{{Cite magazine |title = Why Do We Love the Brontosaurus?|url = http://www.newyorker.com/tech/elements/apatosaurus-brontosaurus-rising|magazine = The New Yorker|access-date = June 18, 2015}}</ref> and personal blog nature (both related<ref>{{Cite journal|title = Bully for Brontosaurus|url = http://scienceblogs.com/gregladen/2015/04/08/bully-for-brontosaurus/|journal = Science|volume = 348|issue = 6231|pages = 168| department = Greg Laden's Blog|access-date = June 18, 2015|first=Greg | last = Laden | date = April 8, 2015|bibcode = 2015Sci...348..168B|pmid = 25859023|doi = 10.1126/science.348.6231.168|doi-access = free}}</ref><ref>{{Cite web|title = Welcome back, Brontosaurus! And other first thoughts on Tschopp et al. (2015)|url = http://svpow.com/2015/04/07/welcome-back-brontosaurus-and-other-first-thoughts-on-tschopp-et-al-2015/|date=April 7, 2015|website=Sauropod Vertebra Picture of the Week|first=Matt |last=Wedel|access-date = June 18, 2015}}</ref> and not<ref>{{Cite web|title = Did You Ever Think You'd See The Day? The Brontosaurus Exists Once Again!|url = http://perezhilton.com/2015-04-07-brontosaurus-reinstated-into-existence-again#.VYM3-UbMjsY|date = April 7, 2015|website = perezhilton.com|access-date = June 18, 2015|archive-date = July 2, 2017|archive-url = https://web.archive.org/web/20170702010223/http://perezhilton.com/2015-04-07-brontosaurus-reinstated-into-existence-again#.VYM3-UbMjsY|url-status = dead}}</ref>), from both<ref>{{Cite news|title=Beloved ''Brontosaurus'' makes a comeback|url=http://www.nature.com/news/beloved-brontosaurus-makes-a-comeback-1.17257|journal=[[Nature (journal)|Nature]]|first=Ewen|last=Callaway|date=April 7, 2015|access-date=June 18, 2015|doi=10.1038/nature.2015.17257|archive-date=August 11, 2020|archive-url=https://web.archive.org/web/20200811052428/https://www.nature.com/news/beloved-brontosaurus-makes-a-comeback-1.17257|url-status=live}}</ref> sides of the debate, from related<ref name="Science Daily-2015">{{Cite news|agency=[[PeerJ]]|title = Brontosaurus is back! Brontosaurus is a unique genus after all |url = https://www.sciencedaily.com/releases/2015/04/150407085256.htm|website = [[Science Daily]]|date=April 7, 2015|access-date = June 18, 2015}}</ref> and unrelated contexts, and from all over the world.<ref>{{Cite news|title = Brontosaurus is back! New analysis suggests genus might be resurrected|url = https://www.theguardian.com/science/2015/apr/07/brontosaurus-is-back-new-analysis-suggests-genus-might-be-resurrected|journal = The Guardian|access-date = June 18, 2015|first = Hannah |last = Devlin | department = Science |date=April 7, 2015}}</ref>

Since Wedel ''et al''{{'s}} 2015 preprint,<ref name="twne15" /> various reconstructions of ''Brontosaurus'' individuals engaging in intraspecific combat based on their study have been made. The art typically depicts the neck-battling hypothesis stipulated by their research. Many of these works are published online under the hashtag "#BrontoSmash".<ref>{{Cite web |title=#Brontosmash |url=https://svpow.com/category/brontosmash/ |access-date=June 17, 2023 |website=Sauropod Vertebra Picture of the Week |language=en}}</ref><ref>{{Cite web |last=Witton |first=Mark |date=October 6, 2015 |title=Mark P. Witton's Blog: New sauropodoramas: Stormy brachiosaurs! Apatosaurine brontosmash! |url=http://markwitton-com.blogspot.com/2015/10/new-sauropodoramas-stormy-brachiosaurs.html |access-date=June 17, 2023 |website=Mark P. Witton's Blog}}</ref>

==References==
{{Reflist}}

==External links==
* {{Commons category-inline}}
* {{Wikibooks inline|Wikijunior Dinosaurs/Brontosaurus}}
* [https://www.youtube.com/watch?v=QiliCc-wvj8 Is Brontosaurus Back? (Youtube video, 11 minutes, 2015)]

{{Sauropodomorpha|D.}}
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[[Category:Diplodocidae]]
[[Category:Dinosaur genera]]
[[Category:Kimmeridgian dinosaurs]]
[[Category:Tithonian dinosaurs]]
[[Category:Morrison Formation]]
[[Category:Fossil taxa described in 1879]]
[[Category:Taxa named by Othniel Charles Marsh]]
[[Category:Dinosaurs of the United States]]
[[Category:Articles containing video clips]]