Class Reptilia Linnaeus, 1758 - reptiles Subclass †Euryapsida Colbert, 1945 see Subclass Diapsida Osborn, 1903 Order †Sauropterygia Owen, 1860 see Superorder Sauropterygia Owen, 1860 Suborder †Plesiosauria Blainville, 1835 see Order Plesiosauria Blainville, 1835 Family †Polycotylidae Williston, 1908