Fossil range: Late Jurassic
| Scientific classification
Megalneusaurus is an extinct genus of large pliosaur that lived in the Sundance Sea during the Kimmeridgian, ~156-152 million years ago, in the Late Jurassic. The genus and type species was based upon ribs, vertebrae, a fore-paddle and fragments of the pectoral girdle discovered in Wyoming, USA in 1895. The species named as Megalneusaurus rex (meaning "great swimming lizard King") in 1898.
However some of this material has since been lost, although new material has been discovered from the same site. Based upon the bones very large size, it appears to have grown to a size comparable to Liopleurodon.
Material from southern Alaska have been referred to Megalneusaurus, although this material is from an individual of much smaller size.
- ^ Knight WC. 1895 A new Jurassic plesiosaur from Wyoming. Science 2: 449.
- ^ Knight WC. 1898. Some new Jurassic vertebrates from Wyoming. American Journal of Science 4: 378-381.
- ^ Wahl WR, Ross M, Massare JA. 2007. Rediscovery of Wilbur Knight’s Megalneusaurus rex site: new material from an old pit. Paludicola 6 (2): 94-104.
- ^ Weems RE, Blodgett RB. 1996. The pliosaurid Megalneusaurus: a newly recognized occurrence in the Upper Jurassic Neknek Formation of the Alaska Peninsula. U.S. Geological Survey Bulletin 2152: 169-175.