After Gill, Renaud, Chapleau, Mayden & Potter, 2003

Older taxonomy after Nelson, 1994 and Froese & Pauly, 2001 [“The Fishbase”]

<==o Petromyzontidae [Petromyzontiformes sensu stricto] (modern lampreys; nykynahkiaiset)
   |-- Geotria australis Gray, 1851 [Exomegas] [Geotriinae] (Pouched lamprey; aasiannnahkiainen)
   |--o Mordacia [Mordaciinae] (etelätyynenmerennahkiaiset)
   |  |-- M. lapicida (Gray, 1851) (Chilean lamprey; chilennahkiainen)
   |  |-- M. mordax (Richardson, 1846) (Australian lamprey; australiannahkiainen)
   |  `-- M. praecox Potter, 1968 (Non-parasitic lamprey)
   `--o Petromyzoninae
      |--o Petromyzontini
      |  |-- Petromyzon marinus Linnaeus, 1758 (Sea lamprey; merinahkiainen)
      |  `--o Ichthyomyzon
      |     |-- I. bdellium (Jordan, 1885) (Ohio lamprey)
      |     |-- I. castaneus Girard, 1858 (Chestnut lamprey)
      |     |-- I. fossor Reighard & Cummins, 1916 (Northern brook lamprey; pohjannahkiainen)
      |     |-- I. gagei Hubbs & Trautman, 1937 (Southern brook lamprey)
      |     |-- I. greeleyi Hubbs & Trautman, 1937 (Mountain brook lamprey)
      |     `-- I. unicuspis Hubbs & Trautman, 1937 (Silver lamprey)
      `--o Lampetrini [Lampetra sensu lato]
         |-- Caspiomyzon wagneri (Kessler, 1870) (Caspian lamprey; kaspiannahkiainen, kaspianmerennahkiainen)
         `--+-- Tetrapleurodon spadicea Bean, 1887 (Mexican lamprey; meksikonnahkiainen) [ssp. => Lampetra?]
            `--+--o Entosphenus (tyynenmerennahkiaiset) [†1,7] [ssp. => Lampetra?]
               |  |--+-- E. lethophaga (Hubbs, 1971) (Pit-Klamath brook lamprey)
               |  |  `-- E. minima (Bond & Kan, 1973) (Miller Lake lamprey)
               |  `--+-- E. tridentata (Richardson, 1836) (Pacific lamprey)
               |     `--+-- E. similis (Vladykov & Kott, 1979) (Klamath river lamprey)
               |        `-- E. macrostoma Beamish, 1982 (Vancouver lamprey)
               `--+--o Lethenteron (jäämerennahkiaiset) [N: 6] [FB: 4]
                  |  |-- L. appendix (DeKay, 1842) (American brook lamprey; amerikannahkiainen)
                  |  |-- L. camtschaticum (Tilesius, 1811) [Lampetra japonica] (Arctic lamprey; idännahkiainen)
                  |  |-- L. kessleri (Anikin, 1905) (Siberian brook lamprey; siperiannahkiainen)
                  |  `-- L. zanandreai (Vladykov, 1955) (Po brook lamprey; italiannahkiainen))
                  `--+--o Eudontomyzon (mustanmerennahkiaiset)
                     |  |-- E. sp.1
                     |  |-- E. morii Berg, 1931 (Korean lamprey)
                     |  |-- E. danfordi Regan, 1911 (Carpathian lamprey; tonavannahkiainen)
                     |  |-- E. hellenicus Vladykov, Renaud, Kott & Economidis, 1982 (Greek brook lamprey; kreikannahkiainen)
                     |  |-- E. mariae (Berg, 1931) (Ukrainian brook lamprey; ukrainannahkiainen)
                     |  `-- E. vladykovi Oliva & Zanandrea, 1959 (Vladykov's lamprey; valakiannahkiainen)
                     `--o Lampetra [incl. Okkelbergia] ()? [N: 7] [FB: 18]
                        |-- L. aepyptera (Abbott, 1860) (Least brook lamprey)
                        |-- L. ayresi (Günther, 1870) (River lamprey)
                        |-- L. fluviatilis (Linnaeus, 1758) (tavallinen nahkiainen, nahkiainen; European river lamprey)
                        |-- L. folletti (Vladykov & Kott, 1976) (Modoc Brook lamprey)
                        |-- L. geminis (Alvarez, 1964) (Mexican brook lamprey)
                        |-- L. hubbsi (Vladykov & Kott, 1976) (Kern brook lamprey)
                        |-- L. lanceolata Kux & Steiner, 1972 (Turkish brook lamprey)
                        |-- L. pacifica Vladykov, 1973 (Pacific brook lamprey; tyynenmerennahkiainen)
                        |-- L. planeri (Bloch, 1784) (European brook lamprey; pikkunahkiainen)
                        |-- L. reissneri (Dybowski, 1869) (Far Eastern brook lamprey)
                        `-- L. richardsoni Vladykov & Follett, 1965 (Western brook lamprey)

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