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 Trichonymphea Hartmann, 1911
                   Order Trichonymphida Hartmann, 1911
                     Family Spirotrichosomidae Hollande & Carruette-Valentin, 1971
                       Genus Spirotrichosoma Sutherland, 1933