Eukaryota Chatton, 1925 - eukaryotes see Domain Eukaryota Chatton, 1925 Opisthokonta Cavalier-Smith, 1987 - opisthokonts see Clade Opisthokonta Cavalier-Smith 1987, nom. cl. inval. Phylum Choanoflagellata Kent, 1880 see Class Choanoflagellatea Cavalier-Smith, 1998