Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Arthropoda Siebold, 1848 - arthropods
     Subphylum Cheliceriformes
       Class Pycnogonida Latreille, 1810 - pycnogonids
         1 Family Nymphonidae Wilson, 1878
         2 Family Callipallenidae Hilton, 1942
         3 Family Phoxichilidiidae Sars, 1891
         4 Family Ammotheidae Dohrn, 1881
         5 Family Tanystylidae see Family Ammotheidae Dohrn, 1881
         6 Family Endeidae Norman, 1908
         7 Family Pycnogonidae Wilson, 1878
         8 Family Colossendeidae Jarzynsky, 1870
         9 Family Austrodecidae Stock, 1954