Chordata Bateson, 1885 - chordates
Status: extant
   Vertebrata Cuvier, 1812 - vertebrates
  Status: extant
     Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
    Status: extant
       Cuculiformes Wagler, 1830 - cuckoos and plantain-eaters
      Status: extant
         Opisthocomidae Swainson, 1837 - hoatzins
        Status: extant