Class Reptilia Linnaeus, 1758 - reptiles Subclass †Synapsida Osborn, 1903 - synapsids see Class Synapsida Osborn, 1903 Order †Pelycosauria Cope, 1878 - pelycosaurs Suborder †Sphenacodontia Marsh, 1878 see Order Pelycosauria Cope, 1878 1 Family †Varanopsidae Romer & Price, 1940 see Family Varanopidae Romer & Price, 1940 2 Family †Sphenacodontidae Marsh, 1878