Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Clade neomura Cavalier-Smith, 1987
             Domain Eukaryota Chatton, 1925 - eukaryotes
               Clade discaria Cavalier-Smith, 2021
                 Clade natates Cavalier-Smith, 2021
                   Phylum Metamonada Grassé, 1952 [coordinate rank]
                     Subphylum Trichozoa Cavalier-Smith, 1997
                       Infraphylum Parabasalia Honigberg, 1973
                         Class Trichomonadea Kirby, 1947
                           Subclass Cristomonadia Cavalier-Smith, 2012
                             Order Spirotrichonymphida Grassé, 1952 [monotypic]
                               Family Holomastigotoididaeᵀ Copeland, 1956
                                 Genus Spirotrichonympha Grassi, 1911
                                   Spirotrichonympha bispira
                                   Spirotrichonympha flagellata
                                   Spirotrichonympha gracilis
                                   Spirotrichonympha leidyi
                                   Spirotrichonympha pulchella