chromalveolates see Supergroup Chromalveolata Adl et al., 2005
   Kingdom Protozoa Goldfuss, 1818 - protozoa
     Infrakingdom Alveolata Cavalier-Smith, 1991 see [unranked] Alveolata Cavalier-Smith, 1991
       Phylum Ciliophora Doflein, 1901 - ciliates
         Subphylum Intramacronucleata Lynn, 1996 - amphiesmates
           Infraphylum Spirotrichia Bütschli, 1889 [monotypic]
             Class Spirotrichea Bütschli, 1889
               1 Genus Protocruzia de Faria, da Cunha & Pinto, 1922
               2 Genus Oxytricha Bory, 1824
               3 Genus Euplotes Ehrenberg, 1830
               4 Genus Tintinnus Schrank, 1803
               5 Genus Stichotricha Perty, 1849
               6 Genus Halteria Dujardin, 1841
               7 Genus Metopus Claparède & Lachmann, 1858