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 Opisthorchiida
                 Suborder Opisthorchiata La Rue, 1957
                   Superfamily Opisthorchioidea Looss, 1899
                     1 Family Opisthorchiidae Lühe, 1901
                     2 Family Heterophyidae Odhner, 1914
                     3 Family Cryptogonimidae Ward, 1917
                     4 Family Acanthostomatidae Poche, 1926
                     5 Family Pachytrematidae
                     6 Family Ratziidae
                     7 Family Tetracladiidae