Microcleidus

Microcleidus is an extinct genus of sauropterygian reptile belonging to the Plesiosauroidea. The species has 40 neck vertebrae and a short tail of 28 vertebrae. Fossils of the genus have been found in France, the Posidonia Shale in Germany and Luxembourg, and the Alum Shale Formation of England.

==Description== thumb|left|Restoration of M. homalospondylus The type species, M. homalospondylus, was the largest, measuring long and weighing . Other species were smaller: M. tournemirensis was about long and weighed , and M. melusinae was about long and weighed .