Brontosaurus excelsus
Pronounced BRON-toh-SORE-us ek-SEL-sus
Sauropoda · Diplodocidae
The "thunder lizard", a long-necked diplodocid from the Late Jurassic Morrison Formation of the western United States. Sunk into Apatosaurus in 1903, it was restored as a separate genus in 2015 after a specimen-by-specimen study.
- Giant
- Long necked
- Quadrupedal
- Famous specimen
- Period
- Jurassic· Kimmeridgian
- Diet
- Herbivore
- Length
- 21–23 m
- Mass
- 15,000–20,000 kg
- Location
- Wyoming, Colorado, Utah, United States
Quick answers
- How big was Brontosaurus excelsus?
- Brontosaurus excelsus was about 21–23 m long. It stood about 3.4–4 m tall at the hips. It weighed about 15–20 t. (Wikipedia: Brontosaurus 2026; Paul 2016)
- When did Brontosaurus excelsus live?
- Brontosaurus excelsus lived during the Late Jurassic, about 154.8–143.1 million years ago. (Paleobiology Database: Brontosaurus occurrences 2026)
- Where have Brontosaurus excelsus fossils been found?
- Fossils of Brontosaurus excelsus have been found in Morrison Formation (Colorado) and United States. (Marsh 1879; Tschopp et al. 2015)
- What did Brontosaurus excelsus eat?
- Brontosaurus excelsus was a herbivore. (Marsh 1879; Tschopp et al. 2015)
- Who named Brontosaurus excelsus, and when?
- Brontosaurus excelsus was described by Othniel Charles Marsh in 1879. (Marsh 1879; Tschopp et al. 2015)
On this page
BRON-toh-SORE-us ek-SEL-sus
- Period
- Jurassic154.8–143.1 Ma
- Diet
- Herbivore
- Length
- 21–23 m
- Mass
- 15–20 t
- Location
- United States
- Classification
- Sauropoda · Diplodocidae
- Described
- 1879, Othniel Charles Marsh
Overview
Brontosaurus excelsus lived in western North America in the Late Jurassic, in the Morrison Formation. Othniel Charles Marsh named it in 1879 from a large skeleton collected at Como Bluff, Wyoming (YPM 1980). That skeleton became the first sauropod ever shown as a complete reconstruction, and made the name famous.
In 1903 Elmer Riggs concluded that Brontosaurus was the same animal as Apatosaurus, named by Marsh two years earlier, and the older name took priority. For more than a century scientists used Apatosaurus while the public kept saying Brontosaurus.
In 2015 Emmanuel Tschopp, Octávio Mateus and Roger Benson compared hundreds of features across diplodocid specimens and found Brontosaurus distinct enough to be a genus again, with three species: B. excelsus, B. parvus and B. yahnahpin. Like its relatives it had a long neck, a massive body and a long, whip-like tail.
Name meaning
From Greek brontē ("thunder") and sauros ("lizard"); excelsus, Latin for "high" or "noble" (Marsh 1879).
Biology & evidence
What scientists think about how this animal lived, and how strong the evidence for each idea is.
Biomechanics
Brontosaurus and its relatives could crack their tails like a whip at supersonic speed.
Evidence level: DisputedA 1997 model said the tail tip could break the sound barrier. A 2022 model including soft tissue found the tip reached only about 30 m/s and that tissues would fail at supersonic speed.
Evidence for / against · 2
Evidence for
Biomechanical model · Supersonic diplodocid tail model
A computer model of the Apatosaurus louisae tail reaching supersonic speed at the tip, like a bullwhip.
Evidence against
Biomechanical model · Diplodocid tail multibody model
A multibody model with soft-tissue strength limits: the tail tip reaches about 30 m/s, far below the speed of sound.
Other
Brontosaurus has three species: B. excelsus, B. parvus and B. yahnahpin.
Evidence level: Moderate evidenceTschopp et al. referred Elosaurus parvus and Eobrontosaurus yahnahpin to Brontosaurus alongside the type species.
Evidence for / against · 1
Evidence for
Phylogenetic inference · Specimen-level phylogeny of Diplodocidae
A phylogenetic analysis scoring 81 diplodocid specimens separately, with a numerical criterion for genus and species boundaries; it recovers Brontosaurus as distinct from Apatosaurus.
Specimen: YPM 1980
Brontosaurus is a genus distinct from Apatosaurus.
Evidence level: Moderate evidenceA specimen-by-specimen analysis found enough differences to separate them again in 2015. Most researchers now use Brontosaurus, but the line between genera is partly a matter of convention.
Evidence for / against · 1
Evidence for
Phylogenetic inference · Specimen-level phylogeny of Diplodocidae
A phylogenetic analysis scoring 81 diplodocid specimens separately, with a numerical criterion for genus and species boundaries; it recovers Brontosaurus as distinct from Apatosaurus.
Specimen: YPM 1980
Size
- Length
- 21–23 m
- Height
- 3.7 mpublished range 3.4–4 m
- Mass
- 15,000–20,000 kg
(75.5 ft)
Based on YPM 1980
(12.1 ft)
Based on YPM 1980 (holotype, femur c. 1.83 m)
Timeline
Periods: Kimmeridgian (154.8–149.2 Ma), Tithonian (149.2–145 Ma), Late Jurassic (161.5–145 Ma)
First and last appearance bounds of B. excelsus in PBDB (Kimmeridgian-Tithonian, PBDB time scale). The holotype comes from the Brushy Basin Member of the Morrison Formation.
Location
Formations
- Morrison Formation · Colorado
- Reed's Quarry 10, Como Bluff, Albany County, Wyoming · Morrison Formation · Wyoming · position approximate
These are the places where fossils have been found, not the full area where the animal lived.
Ecosystem
Lived in: Morrison
156–147 million years ago · floodplain, river system, open woodland, lake
A vast, seasonally dry floodplain crossed by rivers in the western interior of North America in the Late Jurassic, with a wet and a dry season, conifer and fern vegetation along the water and giant sauropods in abundance.
Same ecosystem
Same ecosystem
Same ecosystem
Same ecosystem
Same ecosystem
Same ecosystem
Classification
- cladeDinosauria
- cladeSaurischia
- cladeSauropodomorpha
- cladeSauropoda
- superfamilyDiplodocoidea
- familyDiplodocidae
- subfamilyApatosaurinae
- genusBrontosaurus
- speciesBrontosaurus excelsus
Taxonomic status: Valid
Fossil record
| Catalog number | Status | Institution | Found |
|---|---|---|---|
| YPM 1980 | Holotype | Yale Peabody Museum (YPM) | 1879 |
Which bones each specimen preserves has not been recorded yet.
Gallery
Discovery
- Year described
- 1879
- Described by
- Othniel Charles Marsh
- Type specimen
- YPM 1980
Discovery timeline
1879 · Formally described
Marsh names Brontosaurus excelsus
Marsh names the "thunder lizard" from a skeleton dug at Como Bluff, Wyoming.
People: Othniel Charles Marsh
1903 · Revision
Riggs sinks Brontosaurus into Apatosaurus
Elmer Riggs concludes that Brontosaurus and Apatosaurus are the same genus; the older name Apatosaurus takes priority.
People: Elmer S. Riggs
2015 · Revision
Brontosaurus restored as a separate genus
Tschopp, Mateus and Benson revalidate Brontosaurus with three species.
People: Emmanuel Tschopp
Sources
- (2026). Paleobiology Database: Brontosaurus occurrences. The Paleobiology Database (paleobiodb.org), data service 1.2, accessed 2026-09-23. https://paleobiodb.org/data1.2/occs/list.txt?base_name=Brontosaurus&show=coords,paleoloc,strat,loc,ref&pgm=gplates (opens in a new tab)
- (2026). Wikipedia: Brontosaurus. Wikipedia (English), accessed 2026-09-23. https://en.wikipedia.org/wiki/Brontosaurus (opens in a new tab)
- Conti, S., Tschopp, E., Mateus, O., Zanoni, A., Masarati, P. & Sala, G. (2022). Multibody analysis and soft tissue strength refute supersonic dinosaur tail. Scientific Reports 12. doi:10.1038/s41598-022-21633-2 (opens in a new tab)
- Marsh, O. C. (1879). Notice of new Jurassic reptiles. American Journal of Science, series 3, 18: 501-505.
- Myhrvold, N. P. & Currie, P. J. (1997). Supersonic sauropods? Tail dynamics in the diplodocids. Paleobiology 23: 393-409. doi:10.1017/s0094837300019801 (opens in a new tab)
- Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.
- Tschopp, E., Mateus, O. & Benson, R. B. J. (2015). A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda). PeerJ 3: e857. doi:10.7717/peerj.857 (opens in a new tab)