Hydrachnidia Krantz, 1978 - water mites Superfamily Arrenuroidea Thor, 1900 Family Athienemanniidae Viets, 1922 Subfamily Athienemanniinae Viets, 1922 Genus Stygohydracarus Viets, 1932 1 Subgenus Stygohydracarus (Stygohydracarus) Viets, 1932 2 Subgenus Stygohydracarus (Vicinihydracarus) Cook, 2001