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
                   Clade photaria Cavalier-Smith, 2021
                     Clade eucorta Cavalier-Smith, 2021
                       Superkingdom Corticata Lankester, 1878 - corticates
                         Kingdom Chromista Caval.-Sm. (1981) - chromists
                           Subkingdom Harosa Cavalier-Smith, 2010
                             Clade Sar Adl et al. 2012 [Simpson & Dunthorn 2020]
                               Infrakingdom Halvaria Cavalier-Smith, 2010
                                 Superphylum Heterokonta Caval.-Sm. (1986)
                                   Phylum Bigyra Cavalier-Smith, 1998
                                     Subphylum Opalozoa Cavalier-Smith, 1992
                                       Infraphylum Placidozoa Cavalier-Smith, 2013
                                         Superclass Opalinata Wenyon, 1926
                                           Class Opalineaᵀ Wenyon, 1926
                                             Order Opalinidaᵀ Poche, 1913
                                               Family Opalinidaeᵀ Claus, 1874
                                                 1 Genus Cepedea Metcalf, 1920
                                                 2 Genus Opalinaᵀ Purkinje & Valentin, 1835
                                                 3 Genus Protoopalina Metcalf, 1918
                                                 4 Genus Protozelleriella Delvinquier, Markus & Passmore, 1991
                                                 5 Genus "Zelleriella" Metcalf, 1920, nom. nud.