Eretmosaurus

 
Eretmosaurus is an extinct genus of plesiosaur.
Taxonomic history.
"Eretmosaurus" was coined by Harry Govier Seeley for "Plesiosaurus rugosus" Owen, 1840. Richard Owen had coined the name "P. rugosus" for numerous vertebrae from the Early Jurassic Blue Lias of Gloucestershire and other unspecified locations in the UK. Later, Owen described a headless skeleton (NHMUK 14435) that he assigned to "P. rugosus", and Seeley used NHMUK 14435 as the basis for coining a new genus for this species.