Meyerasaurus is an extinct genus of rhomaleosaurid plesiosaur known from the Early Jurassic of Holzmaden, Baden-Württemberg in southwestern Germany.

It intersected an extremely hard forty centimetres thick layer of Stinkstein chalk, which was deemed worthless.

In May 1906, the famous fossil trader Bernhard Hauff discovered in the dump broken-up boulders containing an uniquely complete and thus very rare plesiosaur skeleton.

Together with a second plesiosaurian skeleton, discovered nearby in shale in November 1906, much later referred to Seeleyosaurus, it was offered for sale.

Financial support by D. Landauer and Victor Fraas allowed the Stuttgarter Königliche Naturalienkabinett to obtain both specimens.

In 2007, Adam Stuart Smith announced that he would shortly name a separate genus for the taxon as Thaumatosaurus was basically a nomen dubium.

[1] Meyerasaurus is known from the holotype SMNS 12478, an articulated and complete skeleton which preserves the skull, exposed in ventral view.