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 Microcotyloidea
                   1 Family Microcotylidae Taschenberg, 1879
                   2 Family Axinidae Monticelli, 1903
                   3 Family Heteraxinidae Unnithan, 1957
                   4 Family Gastrocotylidae Price, 1943
                   5 Family Cemocotylidae
                   6 Family Heteromicrocotylidae Unnithan, 1961
                   7 Family Pyragraphoridae Yamaguti, 1963
                   8 Family Allopyragraphoridae Yamaguti, 1953
                   9 Family Allomicrocotylidae