Class [Reptilia] Linnaeus, 1758 - reptiles
   Subclass Lepidosauria Duméril & Bibron, 1839
     Order Rhynchocephalia Günther, 1867 - tuataras
       1 Suborder †Eosuchoidea Broom, 1914
       2 Suborder Sphenodontoidea Lydekker, 1888
       3 Suborder †Sapheosauroidea Kuhn, 1969 [monotypic]
       4 Suborder †Pleurosauroidea Fitzinger, 1843 [monotypic]
       5 Suborder †Rhynchosauroidea Gervais, 1859
       6 Suborder †Clarazisauroidea Hoffstetter, 1955 see Order Thalattosauria (Merriam, 1905)
       7 Suborder †Thalattosauroidea Merriam, 1904 see Order Thalattosauria (Merriam, 1905)
       8 Suborder †Choristoderoidea Cope, 1876 [monotypic] see Order Choristodera Cope, 1876