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 Eumetazoa Butschli, 1910 see [unranked] Eumetazoa Bütschli, 1910
         Phylum Platyhelminthes Gegenbaur, 1859 - flatworms
           Class Trematoda Rudolphi, 1808 - flukes see Infraclass Trematoda Rudolphi, 1808
             Subclass Digenea Carus, 1863
               Order Echinostomida LaRue, 1957
                 Suborder Echinostomata Szidat, 1939
                   Superfamily Echinostomatoidea Looss, 1902
                     1 Family Echinostomatidae Looss, 1902
                     2 Family Saakotrematidae K. Odening, 1962
                     3 Family Balfouriidae
                     4 Family Ommatobrephidae
                     5 Family Psilostomatidae Odhner, 1911
                     6 Family Philophthalmidae Looss, 1899
                     7 Family Cathaemasiidae Fuhrmann, 1928
                     8 Family Rhopaliidae