[Phylum] Chordata Bateson, 1885 - chordates
   Subphylum Craniata auct.
     Infraphylum Vertebrata Lamarck, 1801 - vertebrates
       Superclass †Thelodontomorphi Jaekel, 1911 [monotypic]
         Class †Thelodonti Jaekel, 1911
           Order †Furcacaudiformes Wilson & Caldwell, 1998 - fork-tailed thelodonts
             1 Family †Furcacaudidae Wilson & Caldwell, 1998
             2 Family †Pezopallichthyidae Wilson & Caldwell, 1998
             3 Family †Nikoliviidae Karatajūtė-Talimaa, 1978
             4 Family †Lanarkiidae Obruchev, 1949
             5 Family †Drepanolepididae Wilson & Märss, 2009
             6 Family †Barlowodidae Märss, Wilson & Thorsteinsson, 2002
             7 Family †Apalolepididae Turner, 1976