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
                   Clade photaria Cavalier-Smith, 2021
                     Clade eucorta Cavalier-Smith, 2021
                       Superkingdom Corticata Lankester, 1878 - corticates
                         Kingdom Chromista Caval.-Sm. (1981) - chromists
                           Subkingdom Hacrobia Okamoto, Chantangsi, Horák, Leander & Keeling, 2009
                             Phylum Haptista Cavalier-Smith, 2003
                               Subphylum Haptophytinaᵀ Caval.-Sm. (2015)
                                 Class Coccolithophyceae Rothm. (1951)
                                   "Heterococcoliths"
                                     "Placoliths"
                                       Order Coccosphaerales Haeckel (1894)
                                         Family Halopappaceae Kamptner (1928)
                                           Genus Calciopappus Gaarder & Ramsfjell (1954)
                                           Genus Halopappusᵀ Lohmann (1912)
                                           Genus Michaelsarsia Gran, in J. Murray & Hjort (1912)
                                           Genus Ophiaster Gran, in J. Murray & Hjort (1912)