Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Craniata Linnaeus, 1758 see Subphylum Craniata auct.
     Pisces
       Class Elasmobranchii Bonaparte, 1838 see Infraclass Elasmobranchii Bonaparte, 1838
         Order Rajiformes Berg, 1940 - skates
           Family Hexatrygonidae Heemstra & Smith, 1980 - sixgill stingrays