Kingdom Protista (Haeckel, 1866) - protists
   Phylum Ciliophora Doflein, 1901 - ciliates
     Class Polyhymenophorea - spirotrichs see Class Spirotrichea Bütschli, 1889
       Subclass Spirotricha see Class Spirotrichea Bütschli, 1889
         Order Hypotrichida Stein, 1859 - hypotrichs see Subclass Hypotrichia (Stein, 1859) Cavalier-Smith, 1993
           Genus Euplotes Ehrenberg, 1830
           Genus Hypotrichidium Ilowaisky, 1921
           Genus Oxytricha Bory, 1824
           Genus Urostyla Ehrenberg, 1830