eukaryotes see Domain Eukaryota Chatton, 1925
   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 Haptophytina Caval.-Sm. (2015)
             Class Coccolithophyceae Rothm. (1951)
               1 Genus Emiliania W.W. Hay & H. Mohler (1967)
               2 Genus Isochrysis M. Parke (1949)
               3 Genus Prymnesium J. Massart (1920)