Colymbosaurus

Colymbosaurus is a genus of cryptoclidid plesiosaur from the Middle-Late Jurassic (Callovian-Tithonian) of the UK and Svalbard, Norway. There are two currently recognized species, C. megadeirus and C. svalbardensis.

==Taxonomy== thumb|left|Scale diagram, presenting the two currently recognised species thumb|left|C. megadeirus life restoration The first remains attributed to Colymbosaurus were described as a new species of Plesiosaurus, P. trochantericus. The holotype of the species, NHMUK PV OR 31787, a humerus (upper arm bone), comes from the Kimmeridgian Kimmeridge Clay Formation of Shotover, Oxfordshire, England. Richard Owen, however, misidentified the bone as a femur, an identification corrected in an 1871 publication on the geology of Oxfordshire.