vertebrates Lamarck, 1801 - vertebrates see Infraphylum Vertebrata Lamarck, 1801
   †Pteraspidimorphi [paraphyletic]
     †Heterostraci Lankester, 1868, sedis mutabilis - heterostracans
       Family †Cyathaspididae Kiaer, 1932, nom. praeval. [paraphyletic]
         1.1 Genus †Allocryptaspis Whitley, 1940
         1.2 Genus †Alainaspis Elliott & Dineley, 1985
         2.1.1 Genus †Poraspis Kiaer, 1930, sedis mutabilis
         2.1.2 †Homalaspidella nitida sedis mutabilis
         2.1.3 Genus †Archaegonaspis nom. illeg., sedis mutabilis see Genus Archegonaspis Jaekel, 1927
         2.1.4 Genus †Americaspis White & Moy-Thomas, 1941, sedis mutabilis
         2.1.5.1 Genus †Anglaspis Jaekel, 1927
         2.1.5.2.1 Genus †Paraliliaspis Novitskaya & Karatajute-Talimaa, 1994
         2.1.5.2.2 Genus †Liliaspis Novitskaya, 1972
         2.1.6.1.1 Genus †Ptomaspis Denison, 1963
         2.1.6.1.2.1 Genus †Athenaegis Soehn & Wilson, 1990
         2.1.6.1.2.2 Genus †Asketaspis Dineley & Loeffler, 1976
         2.1.6.2.1.1.1 Genus †Listraspis Denison, 1964, sedis mutabilis
         2.1.6.2.1.1.2 †Ariaspis ornata Denison, 1963, sedis mutabilis
         2.1.6.2.1.1.3 †Ariaspis arctata Elliott & Swift, 2010, sedis mutabilis
         2.1.6.2.1.2.1 †Homalaspidella borealis Denison, 1963
         2.1.6.2.1.2.2.1 Genus †Tolypelepis Pander, 1856, sedis mutabilis
         2.1.6.2.1.2.2.2 Genus †Cyathaspis Lankester, 1865, sedis mutabilis
         2.1.6.2.1.2.2.3 Genus †Boothiaspis Broad, 1973, sedis mutabilis
         2.1.6.2.2 †Problematic Heterostraci [paraphyletic]
         2.2.1.1 Genus †Irregulareaspis Zych, 1931
         2.2.1.2.1 Genus †Nahanniaspis Dineley & Loeffler, 1976
         2.2.1.2.2 Genus †Dinaspidella Strand, 1934
         2.2.2.1 †Pionaspis amplissima sedis mutabilis
         2.2.2.2 †Pionaspis acuticosta Denison, 1964, sedis mutabilis
         2.2.2.3 Genus †Capitaspis Elliott, 2013, sedis mutabilis
         2.2.2.4.1 Genus †Vernonaspis Flower & Wayland-Smith, 1952, sedis mutabilis
         2.2.2.4.2 Genus †Torpedaspis Broad & Dineley, 1973, sedis mutabilis
         2.2.2.4.3 Genus †Dikenaspis Denison, 1963, sedis mutabilis
         2.2.2.4.4.1.1 Genus †Ulutitaspis Elliott, 1984, sedis mutabilis
         2.2.2.4.4.1.2 Genus †Rachiaspis Soehn, Hanke, Märss & Wilson, 2000, orth. inval., sedis mutabilis see Genus Rhachiaspis Elliott, 1984
         2.2.2.4.4.1.3 Genus †Anchipteraspis Elliott, 1984, sedis mutabilis
         2.2.2.4.4.2.1.1 Genus †Corvaspis Woodward, 1934 [sister group to excluded taxa]
         2.2.2.4.4.2.1.2 [Order] †Traquairaspidida Stensiö, 1958
         2.2.2.4.4.2.2 Order †Pteraspidiformes Berg, 1940