After Froese & Pauly, 2001 [“The Fishbase”]

<==o Polyipnus Olig. Eu. R. Oc. [N: 25] [FB: 31]
   |-- P. aquavitus Baird, 1971
   |-- P. asper Harold, 1994
   |-- P. asteroides Schultz, 1938
   |-- P. bruuni Harold, 1994
   |-- P. clarus Harold, 1994
   |-- P. danae Harold, 1990
   |-- P. elongatus Borodulina, 1979
   |-- P. fraseri Fowler, 1934
   |-- P. indicus Schultz, 1961
   |-- P. inermis Borodulina, 1981
   |-- P. kiwiensis Baird, 1971
   |-- P. laternatus Garman, 1899
   |-- P. latirastrus Last & Harold, 1994
   |-- P. matsubarai Schultz, 1961
   |-- P. meteori Kotthaus, 1967
   |-- P. nuttingi Gilbert, 1905 (Nutting's hatchet fish)
   |-- P. oluolus Baird, 1971
   |-- P. omphus Baird, 1971
   |-- P. ovatus Harold, 1994
   |-- P. parini Borodulina, 1979
   |-- P. paxtoni Harold, 1989
   |-- P. polli Schultz, 1961
   |-- P. ruggeri Baird, 1971
   |-- P. soelae Harold, 1994
   |-- P. spinifer Borodulina, 1979
   |-- P. spinosus Günther, 1887
   |-- P. stereope Jordan & Starks, 1904
   |-- P. surugaensis Aizawa, 1990
   |-- P. tridentifer McCulloch, 1914 (Three-spined hatchetfish)
   |-- P. triphanos Schultz, 1938
   `-- P. unispinus Schultz, 1938

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