Clade Lepidosauria Haeckel 1866 [de Queiroz & Gauthier 2020] see Subclass Lepidosauria Duméril & Bibron, 1839 Clade Rhynchocephalia Günther 1867 [Gauthier, Estes & de Queiroz 1988] see Order Rhynchocephalia Günther, 1867 Clade Sphenodontia Williston 1925 [Evans 2003] Genus †Diphydontosaurus Whiteside, 1986 †Diphydontosaurus avonis Whiteside, 1986