Subphylum [Vertebrata] Cuvier, 1812 - vertebrates
   Class Agnatha Cope, 1889
     Subclass †Thelodonti Kiaer, 1932
       Order †Thelodontiformes Kiaer, 1932
         Family †Nikoliviidae Karatajūtė-Talimaa, 1978
           Genus †Nikolivia Karatajūtė-Talimaa, 1978
             1 †Nikolivia milesi
             2 †Nikolivia auriculata Märss, Wilson & Thorsteinsson, 2002
             x [†Nikolivia elongata Karatajūtė-Talimaa, 1978] see Talivalia elongata (Karatajūtė-Talimaa, 1978)