After Armbruster, 2004, with species from Froese & Pauly, 2001 [“The Fishbase”]

<==o Pterygoplichthini Armbruster, 2004
   |?-o Hemiancistrusannectens -group
   |  `-- “H.annectens (Regan, 1904)
   |--o Pterygoplichthys Gill, 1858
   |  |-- P. barbatus (Steindachner, 1911)
   |  |-- P. etentaculatus (Spix & Agassiz, 1829)
   |  |-- P. parananus Peters, 1881
   |  |-- P. undecimalis (Steindachner, 1878)
   |  `-- P. zuliaensis Weber, 1991
   `--+--o Glyptoperichthys Weber, 1991 [Pterygoplichthys Gill; Armbruster, 2004]
      |  |-- G. gibbiceps (Kner, 1854) (Leopard pleco)
      |  |-- G. joselimaianus Weber, 1991
      |  |-- G. lituratus (Kner, 1854)
      |  |-- G. parnaibae Weber, 1991
      |  |-- G. punctatus (Kner, 1854) (Corroncho)
      |  |-- G. scrophus (Cope, 1874)
      |  `-- G. xinguensis Weber, 1991
      `--+-- Pterygoplichthys zuliaensis Weber, 1991
         `--o Liposarcus Günther, 1864 [Pterygoplichthys Gill; Armbruster, 2004]
            |-- L. anisitsi (Eigenmann & Kennedy, 1903) (Snow pleco)
            |-- L. disjunctivus Weber, 1991
            |-- L. multiradiatus (Hancock, 1828) (Sailfin catfish)
            `-- L. pardalis (Castelnau, 1855)

Reference(s):