Hydrachnidia Krantz, 1978 - water mites Superfamily Arrenuroidea Thor, 1900 Family Momoniidae Viets, 1926 Subfamily Stygomomoniinae Motaş & Tanasachi, 1946 1 Genus Stygomomonia Szalay, 1943 2 Genus Xenomomonia Orghidan, Gruia, Georgesco & Viña Bayés, 1977