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Elasmosaurus was a genus of Plesiosauria that lived around 80.5 million years ago. It is believed that their population went extinct around 65 million years ago during the Cretaceous–Tertiary (K–T) extinction event.


Scientific classification

Kingdom Animalia
Phylum Chordata
Class Reptilia
Superorder Sauropterygia
Order Plesiosauria
Family Elasmosauridae
Genus Elasmosaurus
Species Elasmosaurus platyurus (type species)

Quick Facts

Pronunciation Elas‐mo‐saur‐us
Name meaning Thin-plated lizard
Geological time period Late Cretaceous era, Campanian stage
Size 14 m to 15 m (46 ft to 49 ft) in length
Weight 4200 to 4500 pounds
Diet/Food Squid, fish as well as other sea creatures
Habitat Open ocean

Physical Description

Elasmosaurus had a long neck (around 25 feet) with 71 neck vertebrae that offered a great flexibility to control their head. They had a relatively flat skull with an array of sharp and long teeth (and six teeth per premaxilla). They had four flippers used for swimming; and their long tail is also believed to have at least 18 vertebrae.

Behavior and Adaptation

Its aquatic adaptation restricted it to the marine environment. It is believed that they were were skilled (though not fast) swimmers and inhabited great ocean depths like Dolichorhynchops. They had paddle-shaped flippers that helped them to produce wing-like movements. Researchers believe that they cover long distances in search of breeding grounds. Their long neck used to come a quite ‘handy’ while ambushing a prey in water.

Classification and Species

Several Elasmosaurus species have been in the spotlight since the discovery of this genus. But a review by Ken Carpenter in 1999 showed that the type species, i.e. Elasmosaurus platyurus, is the only valid species belonging to this genus. Other ‘samples’ attributed to this genus are either questionable or they have been listed in other genera – such as, E. morgani has been reclassified as Libonectes, E. snowii as Styxosaurus and E. serpentinus as Hydralmosaurus. It has been noted that Elasmosaurus was closely related to Styxosaurus and Hydralmosaurus.

Fossil Discovery

The type species was first described by Edward Drinker Cope in March, 1868, from a fossil sample discovered in western Kansas by military doctor Theophilus Turner. Bone remains and other specimens have also been found from other parts of the United States, such as Montana and Talkeetna Mountains in Alaska.

Interesting Facts

  • In some accounts, this type species is inaccurately described to have been able to coil its neck like a snake.
  • Most paleontologists believe that Elasmosaurus have probably given birth to live young instead of laying eggs.
  • Elasmosaurus appeared on a TV show called Sea Monsters.
  • The appearance of Nessie, the famed cryptid believed to inhabit Loch Ness in Scotland, resembles Elasmosaurus to a great extent.

Published on September 18th 2015 by under Reptiles.
Article was last reviewed on 20th December 2018.

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