Phylum Chordata Bateson, 1885 - chordates
Count: -
   Subphylum Vertebrata Cuvier, 1812 - vertebrates see Infraphylum Vertebrata Lamarck, 1801
  Count: -
     Class Chondrichthyes Huxley, 1880 - cartilaginous fishes
    Count: -
       Order Hexanchiformes Compagno, 1973 - six-gill sharks
      Count: -
         1 Family Hexanchidae Gray, 1851 - cow sharks
        Count: -
         2 Family Chlamydoselachidae Garman, 1884 - frill sharks
        Count: [*] 1g1s