Children (9 direct children, 9 direct and indirect children):
Arctic lamprey
Lethenteron camtschaticum
Lombardy lamprey
Lethenteron zanandreai
Lethenteron kessleri
Siberian brook lamprey
Lampetra appendix
American brook lamprey
Lethenteron alaskense
Alaskan brook lamprey
Lethenteron ninae
Lethenteron matsubarai
Lethenteron reissneri
Lethenteron japonicum