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 Stichotrichia Small & Lynn, 1985
               Order Stichotrichidaᵀ Fauré-Fremiet, 1961
                 Family Spirofilidae von Gelei, 1929
                   1 Genus Chaetospira Lachmann, 1856
                   2 Genus Stichotricha Perty, 1849
                   3 Genus Hypotrichidium Ilowaisky, 1921
                   4 Genus Atractos Vörösváry, 1950
                   5 Genus Spiretella Borror, 1972
                   6 Genus Mucotrichidium Foissner et al., 1990
                   7 Genus Strongylidium Sterki, 1878
                   8 Genus Urostrongylum Kahl, 1932