Class Reptilia Linnaeus, 1758 - reptiles
   Subclass †Synapsida Osborn, 1903 - synapsids see Class Synapsida Osborn, 1903
     1 Order †Pelycosauria Cope, 1878 - pelycosaurs
     2 Order †Therapsida Broom, 1905 see [unranked] Therapsida Broom, 1905
     3 ?Order †Mesosauria Seeley, 1892 [monotypic]