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
                                 1 Genus Microjoenia Grassi, 1892
                                 2.1 Genus Micromastigotes Hollande & Carruette-Valentin, 1971
                                 2.2 Genus Spironympha Koidzumi, 1917
                                 2.3 Genus Spirotrichonympha Grassi, 1911
                                 2.4 Genus Spirotrichonymphella Grassi, 1917
                                 3.1 Genus Holomastigotoidesᵀ Grassi, 1911
                                 3.2 Genus Rostronympha Duboscq, Grassé & Rose, 1937
                                 4.1 Genus Spiromastigotes Duboscq & Grassé, 1943
                                 4.2 Genus Holomastigotes Grassi, 1892
                                 4.3 Genus Uteronympha Brugerolle, 2006