Hydrachnidia Krantz, 1978 - water mites Superfamily Hygrobatoidea Koch, 1842 Family Unionicolidae Oudemans, 1909 Subfamily Pollicipalpinae Viets, 1924 [monotypic] Genus Pollicipalpus Viets, 1924 1 Subgenus Pollicipalpus (Pollicipalpus) Viets, 1924 2 Subgenus Pollicipalpus (Pollicipalpella) Cook, 1986