[Phylum] [Arthropoda] Siebold, 1848 - arthropods
   Chelicerata Heymons, 1901
     Euchelicerata Weygoldt & Paulus, 1979
       [Subclass] Acari Leach, 1817 - mites and ticks
         [Order] Acariformes Zakhvatkin, 1952 see Superorder Acariformes Zakhvatkin, 1952
           Suborder Trombidiformes Reuter, 1909 see Order Trombidiformes Reuter, 1909
             Infraorder Prostigmata Kramer, 1877 see Suborder Prostigmata Kramer, 1877
               Supercohort Anystides van der Hammen, 1972 see Infraorder Anystina van der Hammen, 1972
                 Cohort Parasitengona Oudemans, 1909 - chiggers, velvet mites, water mites, and their relatives see Hyporder Parasitengona Oudemans, 1909
                   Subcohort Hydracarnidiae Dunlop, Penney & Jekel, 2010, orth. inval. see Subcohort Hydrachnidiae
                     Superfamily Arrenuroidea Thor, 1900
                       01 Genus †Protoarrenurus Cook, 1957
                       02 Family Acalyptonotidae Walter, 1911
                       03 Family Amoenacaridae Smith & Cook, 1997
                       04 Family Arenohydracaridae Cook, 1974
                       05 Family Arrenuridae Thor, 1900
                       06 Family Athienemanniidae Viets, 1922
                       07 Family Bogatiidae Motaş & Tanasachi, 1948
                       08 Family Chappuisididae Motaş & Tanasachi, 1946
                       09 Family Gretacaridae Viets, 1978 see Subfamily Gretacarinae Viets, 1978
                       10 Family Harpagopalpidae Viets, 1924
                       11 Family Hungarohydracacaridae Dunlop, Penney & Jekel, 2010, orth. inval. see Family Hungarohydracaridae Motaş & Tanasachi, 1959
                       12 Family Kantacaridae Imamura, 1959
                       13 Family Krendowskiidae Viets, 1926
                       14 Family Laversiidae Cook, 1955
                       15 Family Mideidae Thor, 1911
                       16 Family Mideopsidae Koenike, 1910
                       17 Family Momoniidae Viets, 1926
                       18 Family Neoacaridae Motaş & Tanasachi, 1947
                       19 Family Nipponacaridae Imamura, 1959
                       20 Family Nudomideopsidae Smith, 1990
                       21 Family Uchidastygacaridae Imamura, 1956 see Family Chappuisididae Motaş & Tanasachi, 1946