Class [Reptilia] Linnaeus, 1758 - reptiles
   Subclass Lepidosauria Duméril & Bibron, 1839
     Order Rhynchocephalia Günther, 1867 - tuataras
       Suborder Sphenodontoidea Lydekker, 1888
         Family Sphenodontidae Cope, 1871 - tuataras
           1 Subfamily †Brachyrhinodontinae Huene, 1948 [monotypic]
           2 Subfamily Sphenodontinae Cope, 1871
           3 Subfamily †Homoeosaurinae Gervais, 1859