Vertebrata Cuvier, 1812 - vertebrates see Infraphylum Vertebrata Lamarck, 1801
   Class Agnatha Cope, 1889 [paraphyletic]
     Subclass †Pteraspidomorphi Goodrich, 1909 see Class Pteraspidomorphi Goodrich, 1909
       Order †Heterostraci Lankester, 1868 - heterostracans see Subclass Heterostraci Lankester, 1868
         Family †Traquairaspididae Kiaer, 1932, nom. praeval.