Vertebrata Cuvier, 1812 - vertebrates
   Class Agnatha Cope, 1889 [paraphyletic]
     Subclass †Pteraspidomorphi Goodrich, 1909 see Class Pteraspidomorphi Goodrich, 1909
       1 Order †Heterostraci Lankester, 1868 - heterostracans see Subclass Heterostraci Lankester, 1868
       2 Order †Thelodontida see Order Thelodonti Jaekel, 1911