Hydrachnidia Krantz, 1978 - water mites
Superfamily Hydryphantoidea Piersig, 1896 - water mites
Family Hydryphantidae Piersig, 1896
01 Subfamily Ankelothyadinae Besch, 1964 [monotypic]
02 Subfamily Chimerathyadinae Mitchell, 2003 [monotypic]
03 Subfamily Cowichaniinae Smith, 1983 [monotypic]
04 Subfamily Cyclothyadinae Lundblad, 1941 [monotypic]
05 Subfamily Diplodontinae Viets, 1936, nom. illeg. [monotypic]
06 Subfamily Eupatrellinae Viets, 1935
07 Subfamily Euthyadinae Viets, 1931
08 Subfamily Hydryphantinae Piersig, 1896
09 Subfamily Mamersinae Viets, 1931 [monotypic]
10 Subfamily Protziinae Koenike, 1909
11 Subfamily Pseudohydryphantinae Viets, 1926
12 Subfamily Tartarothyadinae Viets, 1934 [monotypic]
13 Subfamily Wandesiinae Schwoerbel, 1961