Chordata Bateson, 1885 - chordates
   Class Elasmobranchii Bonaparte, 1838 see Infraclass Elasmobranchii Bonaparte, 1838
     Subclass Selachii see Division Selachii
       Order †Acanthodei Gunnell, 1933 see Class Acanthodii Owen, 1846
         33 Family †Acanthoëssidae see Family Acanthodidae Agassiz, 1844
         33.0 [Family †Acanthodidae Agassiz, 1844]
         34 Family †Ischnacanthidae Woodward, 1891
         34.0 [Family †Ictinocephalidae] see Family Ischnacanthidae Woodward, 1891
         35 Family †Diplacanthidae Bleeker, 1859