Superphylum Deuterostomia Grobben, 1908 - deuterostomes see Infrakingdom Deuterostomia Grobben, 1908
   Phylum Chordata Bateson, 1885 - chordates
     Subphylum Craniata auct. see Subphylum Vertebrata Cuvier, 1812
       Vertebrata (Lamarck, 1801) - vertebrates see Subphylum Vertebrata Cuvier, 1812
         Superclass †Pteraspidomorphi Goodrich, 1909 [monotypic]
           Class †Pteraspidomorphi Goodrich, 1909
             Subclass †Heterostraci Lankester, 1868
               Order †Pteraspidiformes Berg, 1940
                 1 Family †Anchipteraspididae Elliott, 1984
                 2 Family †Protaspididae Randle & Sansom, 2017
                 3 Family †Protopteraspididae Novitskaya, 1983
                 4 Family †Psammosteidae Traquair, 1896
                 5 Family †Pteraspididae Claypole, 1885