Elasmosaurus
Elasmosaurus is a genus of plesiosaur that lived in North America during the Campanian stage of the Late Cretaceous period, at about 80.6 to 77 million years ago. The first specimen was discovered in 1867 near Fort Wallace, Kansas, US, and was sent to the American paleontologist Edward Drinker Cope, who named it E. platyurus in 1868. The generic name means "thin-plate reptile", and the specific name means "flat-tailed". Cope originally reconstructed the skeleton of Elasmosaurus with the skull at the end of the tail, an error which was made light of by the paleontologist Othniel Charles Marsh, and became part of their "Bone Wars" rivalry. Only one incomplete Elasmosaurus skeleton is definitely known, consisting of a fragmentary skull, the spine, and now lost pectoral and pelvic girdles, and a single species is recognized today; other species are now considered invalid or have been moved to other genera. A fragmentary specimen from Germany may belong to this genus.

MCDinosaurhunter · CC BY-SA 3.0 · 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
- ElasmosaurinaePBDB
- Diet
- carnivorePBDB, for Plesiosauria
- Life habit
- aquatic, depth=surfacePBDB, for Plesiosauria
- Motility
- actively mobilePBDB, for Plesiosauria
- Environment
- marinePBDB, for Plesiosauria
- Length
- 14 mWikidata
Time the record covers
At least 6.2 million years on record.
The record covers at least 89.8 Mya to 83.6 Mya. No occurrence read is dated outside 93.9 Mya to 72.2 Mya.
9 occurrences of Elasmosaurus on record, most of them in the Late Cretaceous. 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
9 occurrences- Late Cretaceous100%
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
- Pierre Shale Formation · Montana Group2
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The named rock units Elasmosaurus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 7 occurrences have no formation on record, which is common for older literature.
Elasmosaurus and its relatives
Late CretaceousWhere Elasmosaurus and its relatives were recorded in the Late Cretaceous.
Found in the same rock
56 taxa- Inoceramus3 sites
- Damesites semicostatus2 sites
- Inoceramus teshioensis2 sites
- Anagaudryceras1 site
- Anisomyon1 site
- Aporrhais biangulata1 site
- Brunonia1 site
- Callista1 site
- Chlamys1 site
- Damesites damesi1 site
- Dosiniopsis deweyi1 site
- Empo1 site
- Enchodus1 site
- Enchodus carinatus1 site
- Entalis1 site
- Eupachydiscus haradai1 site
- Fasciolaria1 site
- Gaudryceras1 site
- Gaudryceras (Gaudryceras) denseplicatum1 site
- Heteroceras1 site
- Ichthyodectes1 site
- Inoceramus amakusensis1 site
- Inoceramus crispii barbabini1 site
- Inoceramus ezoensis1 site
The Paleobiology Database records 9 sites for Elasmosaurus, 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
4 references- Preliminary report on the Cretaceous reptile fossils from Hokkaido5
- Vampyromorph: past and present - Cretaceous Vampyromorph (Coleoidea: Cephalopoda) as the diet of plesiosaurs2
- A new mosasaur from the Fort Pierre1
- On a new large enaliosaur1
Each of the 9 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. 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 content2
Picture of Elasmosaurus
- Source
- Wikipedia/Commons
- Credit
- MCDinosaurhunter
- Licence
- CC BY-SA 3.0
- Commercial use
- the licence allows it
3D model
- Source
- Sketchfab
- Credit
- seth the yutyrannus
- Licence
- CC Attribution
- Commercial use
- cannot be read from the licence given — check the record
Smithsonian Open Access was not reached for this taxon, so this list is what the others held rather than everything there is.
The description on this site
- 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 itElasmosaurinae through timeFormations of the Late CretaceousThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Cope 1868