Apatosaurus
Apatosaurus is a genus of herbivorous sauropod dinosaur that lived in North America during the Late Jurassic period. Othniel Charles Marsh described and named the first-known species, Apatosaurus ajax, in 1877, and a second species, Apatosaurus louisae, was discovered and named by William H. Holland in 1916. Apatosaurus lived about 152 to 151 million years ago (mya), during the late Kimmeridgian to early Tithonian age, and are now known from fossils in the Morrison Formation of modern-day Colorado, Oklahoma, New Mexico, Wyoming, and Utah in the United States. Apatosaurus had an average length of 21–23 m (69–75 ft), and an average mass of 16.4–22.4 t. A few specimens indicate a maximum length of 11–30% greater than average and a mass of approximately 33 t.

AbstractionBlue · CC BY-SA 4.0 · via Wikipedia/Commons. May be a photograph of a specimen, or an artist’s reconstruction — an interpretation of a skeleton, since colour and soft tissue are almost never preserved.
On record
Recorded, not inferred- Sits inside
- ApatosaurinaePBDB
- Diet
- herbivorePBDB, for Sauropoda
- Life habit
- ground dwelling, gregariousPBDB, for Sauropoda
- Motility
- actively mobilePBDB, for Sauropoda
- Environment
- terrestrialPBDB, for Sauropoda
- Length
- 22.8 mWikidata
- Mass
- 22.4 tonneWikidata
Time the record covers
At least 3 million years on record.
The record covers at least 152.21 Mya to 149.2 Mya. No occurrence read is dated outside 157.9 Mya to 143.1 Mya.
67 occurrences of Apatosaurus on record, most of them in the Late Jurassic. Bar height is expected occurrences, not a count: each fossil is spread across the span it is dated to, so a tall narrow bar means tight dating and a low wide one means loose.
When
67 occurrences- Late Jurassic100%
These are dates about fossils, not the animal: the record can only begin after it arose and end before it died out, so either end may reach further. Shares are expected occurrences: a fossil dated to a span is counted partly in each period it straddles. More on what this infers.
Found in
1 formation
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The named rock units Apatosaurus has been recovered from, largest first. Drawn where the rock is now, not where it formed.
Apatosaurus and its relatives
Late JurassicWhere Apatosaurus and its relatives were recorded in the Late Jurassic.
Found in the same rock
174 taxa- Camarasaurus31 sites
- Stegosaurus23 sites
- Allosaurus21 sites
- Diplodocus19 sites
- Barosaurus11 sites
- Camptosaurus11 sites
- Allosaurus fragilis10 sites
- Ceratosaurus10 sites
- Brachiosaurus9 sites
- Sauropoda9 sites
- Theropoda8 sites
- Diplodocinae7 sites
- Dinosauria6 sites
- Diplodocidae6 sites
- Glyptops6 sites
- Ornithopoda5 sites
- Torvosaurus tanneri5 sites
- Archosauria4 sites
- Crocodylia4 sites
- Haplocanthosaurus4 sites
- Nanosaurus agilis4 sites
- Pterosauria4 sites
- Testudines4 sites
- Allosaurus jimmadseni3 sites
The Paleobiology Database records 62 sites for Apatosaurus, and this reads all of them. The number is how many of those sites it was catalogued from too. The 24 sharing the most are listed.
This is not a list of everything alive at the time. It is only what has come out of the same ground as this animal and been written down.
Entered from
33 references- Paleoecological analysis of the vertebrate fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain region, U.S.A.16
- Biostratigraphy of dinosaurs in the Upper Jurassic Morrison Formation of the Western Interior, U.S.A.12
- 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 clade5
- Marsh's Dinosaurs: The Collections from Como Bluff3
- A new specimen of Torvoaurus tanneri originally collected by Elmer Riggs2
- Bone modification features on sauropod remains (Dinosauria) from the Freezeout Hills Quarry N (Morrison Formation) of southeastern Wyoming and their contribution to fine-scale paleoenvironmental interpretation2
- Taphonomic analysis of a dinosaur feeding site using Geographic Information Systems (GIS), Morrison Formation, southern Bighorn Basin, Wyoming, USA1
- Palaeontological discoveries at Curecanti National Recreation Area and Black Canyon of the Gunnison National Park, Upper Jurassic Morrison Formation, Colorado1
- New juvenile sauropod material from western Colorado, and the record of juvenile sauropods from the Upper Jurassic Morrison Formation1
- New sauropod dinosaur specimens found near Moab, Utah, and the sauropod fauna of the Morrison Formation1
- A nearly complete skeleton of a baby sauropod from the lower Morrison Formation of the Howe Stephens Quarry, Wyoming: "little steps" into diplodocid ontogeny and taxonomy1
- Historical update: paleontological excavation in the Como Region1
Each of the 67 occurrences read was entered from one of these publications, ordered by how many each accounts for. This is not a search for papers mentioning the name. 21 further references are not listed. Entries link to doi.org where the Paleobiology Database holds an identifier, and to its own record where it does not. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.
Media and terms
Media content3
Picture of Apatosaurus
- Source
- Wikipedia/Commons
- Credit
- AbstractionBlue
- Licence
- CC BY-SA 4.0
- Commercial use
- the licence allows it

Photogrammetry
- Source
- MorphoSource
- Licence
- In Copyright
- Commercial use
- cannot be read from the licence given — check the record
- Specimen
- Apatosaurus excelsus · AMNH:FARB:339
3D model
- Source
- Sketchfab
- Licence
- CC Attribution-NonCommercial
- Commercial use
- the licence does not allow it
This entry was cached before the site began recording what Smithsonian Open Access did, so a search that failed cannot be told from one that found nothing.
The description on this site
- Source
- Wikipedia, “Apatosaurus”
- Licence
- CC BY-SA 4.0
This is what the site found, which is not the same as what exists.
Keep going
What may have been alongside itApatosaurinae through timeFormations of the Late JurassicThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Marsh 1877