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
                 Family †Protopteraspididae Novitskaya, 1983
                   1 Genus †Protopteraspis Leriche, 1924