[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Kingdom Protista (Haeckel, 1866) - protists
     Phylum Protozoa (Goldfuss, 1818) C.T. von Siebold, 1854 see Kingdom Protozoa Goldfuss, 1818
       Subphylum Sarcomastigophora see Phylum Sarcomastigophora Honigberg & Balamuth, 1963
         Class Opalinata Wenyon, 1926 see Superclass Opalinata Wenyon, 1926
           Order Opalinida Poche, 1913
             1 Genus Opalina Purkinje & Valentin, 1835
             2 Genus Cepedia see Genus Cepedea Metcalf, 1920