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 neokaryotes Cavalier-Smith 1993 - mitochondrial eukaryotes
                 Clade neozoa Cavalier-Smith 1993
                   Superkingdom Corticata Lankester, 1878
                     Kingdom Chromista Caval.-Sm. (1981) - chromists
                       Subkingdom Harosa Cavalier-Smith, 2010
                         Infrakingdom Halvaria Cavalier-Smith, 2010
                           Superphylum Heterokonta Caval.-Sm. (1981)
                             Phylum Bigyra Cavalier-Smith, 1998
                               Subphylum Opalozoa Cavalier-Smith, 1991
                                 Infraphylum Placidozoa Cavalier-Smith, 2013
                                   Superclass Opalinata Wenyon, 1926
                                     Class Opalineaᵀ Wenyon, 1926
                                       Order Opalinidaᵀ Poche, 1913
                                         Family Opalinidaeᵀ Claus, 1874
                                           Genus Protoopalina Metcalf, 1918