Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Nematoda Gegenbaur, 1859 - round worms
     Class Enoplea Inglis, 1983
       Subclass Enoplia Pearse, 1942
         Superorder Enoplica Hodda, 2007
           Order Trefusiida Lorenzen, 1981
             Suborder Trefusiina Siddiqi, 1983
               Superfamily Trefusioidea Gerlach, 1966
                 1 Family Lauratonematidae Gerlach, 1953
                 2 Family Simpliconematidae Blome & Schrage, 1985
                 3 Family Trefusiidae Gerlach, 1966
                 4 Family Xenellidae De Coninck, 1965 see Family Xennellidae De Coninck, 1965