vertebrates Lamarck, 1801 - vertebrates see Infraphylum Vertebrata Lamarck, 1801
   Class †Pteraspidomorphi Goodrich, 1909 see Class Pteraspidomorpha
     Subclass †Heterostraci Lankester, 1868
       Order †Cyathaspidiformes Kiaer, 1930
         1 Family †Cyathaspididae Kiaer, 1932, nom. praeval.
         2 Family †Irregulareaspididae Denison, 1964 see Subfamily Irregulareaspidinae Denison, 1964
         3 Family †Poraspididae Kiaer, 1932 see Subfamily Poraspidinae Denison, 1964
         4 Family †Ctenaspididae Kiaer, 1930, nom. praeval.