Hydrachnidia Krantz, 1978 - water mites Superfamily Arrenuroidea Thor, 1900 Family Chappuisididae Motaş & Tanasachi, 1946 Subfamily Uchidastygacarinae Imamura, 1956 [monotypic] Genus Uchidastygacarus Imamura, 1956 1 Subgenus Uchidastygacarus (Uchidastygacarus) Imamura, 1956 2 Subgenus Uchidastygacarus (Imamurastygacarus) Cook, 1974