Two prehistoric marine reptiles (Elasmosaurus) catching fish underwater


Plesiosauria includes the large, carnivorous, marine reptiles the Plesiosaurs and Pliosaurs. They used their flippers to propel themselves through the water, rather like a turtle except that they used both the front and rear flippers. Scientists were intrigued to find that using all four flippers didn't make them faster. In fact, the opposite was true, as turbulence from the front flippers interfered with the efficiency of the rear flippers. However, four flippers did make it easier to get going and brake. So while Plesiosaurs and Pliosaurs may not have been ultra-speedy, they would have been agile and quick to react to passing prey.

Scientific name: Plesiosauria

Rank: Order

Common names:

Near to lizard

Explore this group


Discover what these behaviours are and how different plants and animals use them.

Additional data source: Animal Diversity Web

When they lived

Discover the other animals and plants that lived during the following geological time periods.

What killed them

Cretaceous-Tertiary mass extinction Cretaceous-Tertiary mass extinction
The Cretaceous-Tertiary mass extinction - also known as the K/T extinction - is famed for the death of the dinosaurs. However, many other organisms perished at the end of the Cretaceous including the ammonites, many flowering plants and the last of the pterosaurs.


  1. Life
  2. Animals
  3. Vertebrates
  4. Reptiles
  5. Sauropterygia
  6. Plesiosauria