Phylum [Vertebrata] Lamarck, 1801 see Infraphylum Vertebrata Lamarck, 1801
   Class Agnatha Cope, 1889
     Subclass †Pteraspidomorphi Goodrich, 1909 see Class Pteraspidomorphi Goodrich, 1909
       Order †Heterostraci Lankester, 1868 - heterostracans see Subclass Heterostraci Lankester, 1868
         1 Genus †Arandaspis Ritchie & Gilbert-Tomlinson, 1977
         2 Genus †Drepanaspis Schlüter, 1887
         3 Family †Pteraspidae see Family Pteraspididae Claypole, 1885