Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         [crown] 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 Fornicata Simpson, 2003
                         Class Eopharyngea Cavalier-Smith, 1993
                           Order Diplomonadida Wenyon, 1926 - diplomonads
                             Suborder Distomatina Senn, 1900
                               Family Spironucleidae Cavalier-Smith, 1996 [monotypic]
                                 Genus Spironucleusᵀ Lavier, 1936 [paraphyletic]
                                   Spironucleus barkhanus Sterud et al., 1997
                                   Spironucleus columbae
                                   Spironucleus elegans
                                   Spironucleus meleagridis
                                   Spironucleus muris