Water Mites (Acari: Hydrachnidiae) Found in Water Supply Systems in Japan

A large number of water mites of the species Kawamuracarus elongatus Uchida, 1937 were found to accumulate on a water-filtering sieve in a drinking water treatment plant in Fukuoka, Japan. Such a situation probably could be caused by the temporal reduction of the dissolved oxygen in the filtration bed. Newly recognized morphological features of this species are noted based on the specimens collected in Fukuoka. Further, water mites discovered so far in water supply systems in Japan are reviewed, and more accurate information of water mites as organisms of water supplies is provided.