Hydrorion is a genus of plesiosaur from the Toarcian Age of the Lower Jurassic. It is only known from multiple specimens, all discovered in the Posidonia Shale of south-western Germany. The only speci

Anningasaura is an extinct genus of basal plesiosaur. It is known from a single type species, A. lymense, discovered in Early Jurassic rocks of Lyme Regis in the United Kingdom.