living organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Superkingdom Eukaryotae see Domain Eukaryota Chatton, 1925
     Kingdom Animalia Linnaeus, 1758 - animals
       Subkingdom Protozoa Goldfuss, 1818 see Kingdom Protozoa Goldfuss, 1818
         Phylum Ciliophora Doflein, 1901 - ciliates
           Class Oligohymenophora see Class Oligohymenophorea de Puytorac et al., 1974
             Subclass Peritricha Stein, 1859 - peritrichs see Subclass Peritrichia Stein, 1859
               Order Peritrichida Stein, 1859 see Subclass Peritrichia Stein, 1859
                 Suborder Sessilina Kahl, 1933 see Order Sessilida Kahl, 1933
                   Family Ophrydiidae Ehrenberg, 1838
                     1 Genus Gerda Claparède & Lachmann, 1858
                     2 Genus Ophrydium Bory de St. Vincent, 1827