Genus: Colymbosaurus SEELEY, 1874
Etymology: Greek, kolymbo, “dive”, Greek, sauros, “lizard”: Dive lizard.

Species: trochanterius (OWEN, 1840) SEELEY, 1874

Referred material:

= Plesiosaurus megadeirus SEELEY, 1869
= Colymbosaurus megadeirus (SEELEY, 1869) SEELEY, 1874

Referred material:

Locality: Haddenham, Buckinghampshire County, England, Southern United Kingdom.

Horizon: Kimmeridge Clay.


Age: Kimmeridgian Stage, Middle Malm Epoch, Late Jurassic.


SMC J 63919: Incomplete vertebral column (36 cervicles, four pectoral, 17 dorslas, three sarals and 28 caudal vertebrae).

Note: Rounded, anteroventrally projecting, spur-like expanseions are present on the venral surfaces of cervicals 26-28, and 31 (SASSOON, 2019).