Phylum Chordata Bateson, 1885 - chordates
   Subphylum Vertebrata Cuvier, 1812 - vertebrates
     Class Reptilia Linnaeus, 1758 - reptiles
       Subclass Lepidosauria Duméril & Bibron, 1839
         Order Rhynchocephalia Günther, 1867 - tuataras
           Family †Claraziidae Peyer, 1936
           Family †Pleurosauridae Lydekker, 1888
           Family †Rhynchosauridae Huxley, 1867
           Family †Sapheosauridae Baur, 1895 see Family Sphenodontidae Cope, 1871
           Family Sphenodontidae Cope, 1871 - tuataras