Subphylum [Vertebrata] Cuvier, 1812 - vertebrates Class Agnatha Cope, 1889 Subclass †Thelodonti Kiaer, 1932 Order †Furcacaudiformes Wilson & Caldwell, 1998 - forktail thelodonts Family †Furcacaudidae Wilson & Caldwell, 1998 Genus †Canonia Vieth, 1980 †Canonia costulata Märss, Wilson & Thorsteinsson, 2002