Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Nematoda Gegenbaur, 1859 - round worms
     Class Chromadorea Inglis, 1983
       Subclass Plectia Hodda, 2007
         Superorder Rhabditica Hodda, 2007
           Order Spirurida Railliet, 1914
             Suborder Spirurina Railliet & Henry, 1915
               Superfamily Thelazioidea Railliet, 1910
                 1 Family Pneumospiruridae Wu & Hu, 1938
                 2 Family Rhabdochonidae Travassos, Artigas & Pereira, 1928, incertae sedis
                 3 Family Thelaziidae Railliet, 1910