Chordata Bateson, 1885 - chordates
   Class †Ostracophori
     Order †Osteostraci Lankester, 1868 - osteostracans see Order Cephalaspidiformes Halstead Tarlo, 1967
       14 Family †Cephalaspidae Agassiz, 1844 see Family Cephalaspididae Agassiz, 1844, nom. praeval.
       15 Family †Ateleaspidae Traquair, 1899 [monotypic] see Family Ateleaspididae Traquair, 1899, nom. praeval.
       16 Family †Thyestidae Rohon, 1892
       16.0 [Family †Menaspidae Woodward, 1891]
       17 Family †Odontodontidae nom. imperf.
       17.0 [Family †Tremataspidae Woodward, 1891] see Family Tremataspididae Woodward, 1891, nom. praeval.
       18 Family †Euphaneropidae Woodward, 1900 [monotypic]