Hydrachnidia Krantz, 1978 - water mites Superfamily Hygrobatoidea Koch, 1842 Family Aturidae Thor, 1900 Subfamily Axonopsinae Viets, 1929 Genus Hexaxonopsis Viets, 1926 1 Subgenus Hexaxonopsis (Hexaxonopsis) Viets, 1926 2 Subgenus Hexaxonopsis (Plesiobrachypoda) Viets, 1942