Superphylum Deuterostomia Grobben, 1908 - deuterostomes see Infrakingdom Deuterostomia Grobben, 1908
   Phylum Chordata Bateson, 1885 - chordates
     Subphylum Craniata auct.
       Infraphylum Vertebrata Lamarck, 1801 - vertebrates
         Superclass †Pteraspidomorphi Goodrich, 1909 [monotypic]
           Class †Pteraspidomorpha
             Subclass †Heterostraci Lankester, 1868
               1 †Cardipeltida see Order Cardipeltiformes Bryant, 1933
               2 †Corvaspidida see Order Corvaspidiformes Stensiö, 1964
               3 †Lepidaspidida see Order Lepidaspidiformes Halstead, 1993
               4 †Tesseraspidida see Order Tesseraspidiformes Halstead, 1962
               5 †Traquairaspidiformes Stensio, 1958
               6 †Tolypelepidida see Order Tolypelepidiformes
               7 Order †Cyathaspidiformes Kiaer, 1930
               8 Order †Pteraspidiformes Berg, 1940