A New Feather Mite Species of the Genus Metanalges (Acariformes: Analgidae) from the Okinawa Rail, Hypotaenidia okinawae (Gruiformes: Rallidae), in Okinawa Island, Japan

The Okinawa Rail, Hypotaenidia okinawae (Yamashina and Mano, 1981), is a flightless bird restricted to the northern part of Okinawa Island, Ryukyu Islands, Japan. A new feather mite species, Metanalges (M.) agachi sp. n. (Analgidae: Megniniinae), is described from the Okinawa Rail. The new species is distinguished from the closest species, M. (M.) curtus Gaud and Mouchet, 1959, in having, in males, legs III extending slightly beyond the bases of setae h2, and setae ps1 approximately equidistant from setae h2 and h3, and in females, ventral setae 4a almost extending to the posterior margin of opisthosoma. This is the first report of feather mites associated with this avian host and the first record of the genus Metanalges Trouessart, 1919 in Japan. As the Okinawa Rail is considered to be at high risk of population decline, the new feather mite is thought to be under the risk of extinction.