Chordata Bateson, 1885 - chordates
   1 Class Leptocardii [monotypic] see Subphylum Cephalochordata Owen, 1846
   2 Class Marsipobranchii see Class Cyclostomata
   3 Class †Ostracophori
   4 Class †Arthrodira Woodward, 1891 - arthrodires see Order Arthrodiriformes
   5 Class Elasmobranchii Bonaparte, 1838 see Subclass Elasmobranchii Bonaparte, 1838
   6 Class Pisces Linnaeus, 1758 see Superclass Pisces Linnaeus, 1758