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 Monogenea Carus, 1863 see Infraclass Monogenea
               Suborder Polyopisthocotylea Odhner, 1912 see Subclass Polyopisthocotylea
                 Superfamily Polystomatoidea Gamble, 1896
                   Family Polystomatidae Gamble, 1896
                     Genus Polystoma Zeder, 1800