eukaryotes see Domain Eukaryota Chatton, 1925
   Kingdom Protozoa Goldfuss, 1818 [paraphyletic] - protozoa
     Subkingdom Eozoa Cavalier-Smith, 1997 [paraphyletic] see Infrakingdom Eozoa Cavalier-Smith, 1997
       Infrakingdom Excavata T. Cavalier-Smith, 2002 [paraphyletic] see Supergroup Excavata Cavalier-Smith, 2002
         Phylum Loukozoa Cavalier-Smith, 1999 [paraphyletic]
           Subphylum Metamonada Grassé, 1952 see Phylum Metamonada Grassé, 1952
             Infraphylum Trichozoa Cavalier-Smith, 1997 see Subphylum Trichozoa Cavalier-Smith, 1997
               Superclass Parabasalia Honigberg, 1973 - parabasalids see Infraphylum Parabasalia Honigberg, 1973
                 Class Trichomonadea Kirby, 1947
                   Subclass Eotrichomonadia Cavalier-Smith, 2012 [paraphyletic]
                     Order Trichomonadida Kirby, 1947 - trichomonads
                       Suborder Trichomonadina Cavalier-Smith, 2012 [monotypic]
                         Family Trichomonadidae Chalmers & Pekkola, 1918
                           1 Genus Trichomonas Donné, 1836
                           2 Genus Pentatrichomonas Mesnil, 1914
                           3 Genus Cochlosoma Kotlán, 1923