Class Sauropsida Scientific name Megalneusaurus rex | Suborder Pliosauroidea Rank Genus | |
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Similar Simolestes, Archaeonectrus, Plesiopleurodon, Maresaurus, Bishanopliosaurus |
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.
Contents

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.

Description

Megalneusaurus is said to reach lengths of 7.6–9.7 m (25–32 ft), though there are some estimates that propose a length of 11 meters.
Habitat

Megalneusaurus hunted in the warm waters of the Sundance Sea some 150 million years ago. The large, inland sea hosted a wide array of marine reptiles.
Diet
While no stomach contents of Megalneusaurus have been discovered, it is reasonable to assume that it ate medium sized marine reptiles such as the ichthyosaur Ophthalmosaurus, and the cryptocleid plesiosaur, Pantosaurus.