[Phylum] Chordata Bateson, 1885 - chordates
   Subphylum Craniata auct.
     Infraphylum Vertebrata Lamarck, 1801 - vertebrates
       Superclass †Pteraspidomorphi Goodrich, 1909 [monotypic]
         Class †Pteraspidomorpha
           Subclass †Heterostraci Lankester, 1868
             Order †Cyathaspidiformes Kiaer, 1930
               Suborder †Cyathaspidoidei
                 Family †Cyathaspididae Kiaer, 1932, nom. praeval.
                   01 Genus †Poraspis Kiaer, 1930
                   02 Genus †Dinaspis Kiaer, 1932, nom. illeg. see Genus Dinaspidella Strand, 1934
                   03 Genus †Palaeaspis Claypole, 1884, nom. illeg. see Genus Americaspis White & Moy-Thomas, 1941
                   04 Genus †Anglaspis Jaekel, 1927
                   05 Genus †Cyathaspis Lankester, 1865
                   06 Genus †Diplaspis Matthew, 1887 see Genus Cyathaspis Lankester, 1865
                   07 Genus †Dinaspidella Strand, 1934
                   08 Genus †Irregulareaspis Zych, 1931
                   09 Genus †Dictyaspis Kiaer, 1932, nom. illeg. see Genus Dictyaspidella Strand, 1934
                   10 Genus †Americaspis White & Moy-Thomas, 1941
                   11 Genus †Dictyaspidella Strand, 1934 see Genus Irregulareaspis Zych, 1931
                   12 Genus †Torpedaspis Broad & Dineley, 1973
                   13 Genus †Boothiaspis Broad, 1973