†Nothosaurops Leidy 1870 (plesiosaur)
Parent taxon: Plesiosauria according to S. W. Williston 1903
Sister taxa: Aptychodon, Embaphias, Eoplesiosaurus, Eretmosaurus, Gymocetus, Hexatarsostinus, Hunosaurus, Iserosaurus, Muraenosauridae, Namuncurania, Neoplesiosauria, Orophosaurus, Plesiosauroidea, Pliosauridae, Pliosauroidea, Rhomaleosauridae, Scarrisaurus, Stratesaurus, Sulmosaurus, Taphrosaurus, Tremamesacleididae, Uronautes, Polyptychodon hudsoni, Polyptychodon interruptus
Subtaxa: none
Ecology: aquatic carnivore