[Phylum] Chordata Bateson, 1885 - chordates
   Subphylum Craniata auct.
     Infraphylum Vertebrata Lamarck, 1801 - vertebrates
       Superclass †Pteraspidomorphi Goodrich, 1909 [monotypic]
         Class †Pteraspidomorpha
           1 Subclass †Astraspida Berg, 1940 [monotypic]
           2 Subclass †Arandaspida
           3 Subclass †Heterostraci Lankester, 1868