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 †Tesseraspidida
                 1 Genus †Tesseraspis Wills, 1935