organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain eukaryotes see Domain Eukaryota Chatton, 1925
     alveolates Cavalier-Smith see [unranked] Alveolata Cavalier-Smith, 1991
       Phylum Ciliophora Doflein, 1901 - ciliates
         Subphylum Intramacronucleata Lynn, 1996 - amphiesmates
           Class Spirotrichea Bütschli, 1889
             Subclass Choreotrichia Small & Lynn, 1985
               Order Tintinnida Kofoid & Campbell, 1929
                 Family Metacylididae Kofoid & Campbell, 1929
                   Genus Helicostomella Jörgensen, 1924