Subphylum [Vertebrata] Cuvier, 1812 - vertebrates Class Agnatha Cope, 1889 Subclass †Thelodonti Kiaer, 1932 Order †Thelodontiformes Kiaer, 1932 Family †Nikoliviidae Karatajūtė-Talimaa, 1978 Genus †Chattertonodus Märss, Wilson & Thorsteinsson, 2002 [monotypic] †Chattertonodus cometoidesᵀ Märss, Wilson & Thorsteinsson, 2002