Yaeyama little horseshoe bat

Rhinolophus perditus was first described by Knud Andersen in 1918, based on a female specimen in the Natural History Museum that had been purchased by Alan Owston (B.M. no. 5.11.3.15); the type locality is given as "Ishigaki, southern Liu-Kiu", and its relatively large teeth are noted.^{[2]: 376–7} Included in Mammal Species of the World (2005) as Rhinolophus cornutus perditus,^[3]: 353 i.e., as a subspecies of the Japanese little horseshoe bat, the Yaeyama little horseshoe bat is now treated as an independent species by authorities including the IUCN^[1] and the editors of Handbook of the Mammals of the World^[4] and Wild Mammals of Japan (2015), published under the auspices of the Mammal Society of Japan.^[5] The last two works also include Imaizumi's horseshoe bat (protonym, Rhinolophus imaizumii) as a subspecies of the Yaeyama little horseshoe bat, under the combination R. p. imaizumii.^[4][5] In its native Japan, the bat is known by the vernacular name Yaeyama kokikugashira-kōmori (ヤエヤマコキクガシラコウモリ).^[5]

Two subspecies are "tentatively" recognized:^[4]

• R. p. perditus Andersen, 1918^[2] — Ishigaki Island, Taketomi Island
• R. p. imaizumii Hill & Yoshikuki, 1980^[6] — Iriomote Island, Kohama Island

The bat's external morphology resembles that of the Japanese little horseshoe bat (Rhinolophus cornutus) and Okinawa little horseshoe bat (Rhinolophus pumilus), differences including a larger nose-leaf and skull length, and shorter tibia than the Okinawa little horseshoe bat.^[5] The constant frequency (CF) echolocation values of its calls are also lower than those of these other two species.^[5]

The Yaeyama little horseshoe bat is nocturnal and, though active all year round, is believed to hibernate but with frequent awakening in order to forage .^[5] It roosts in caves, often together with the Ryūkyū long-fingered bat (Miniopterus fuscus), as well as in abandoned mines, and old bomb shelters.^[4][5] The bat's diet consists of insects, in particular Lepidoptera (butterflies and moths), Coleoptera (beetles), Hymenoptera (bees, wasps, ants), and Diptera (flies), for which they forage mainly in areas of woodland.^[5] Females are monoestrous and form "maternity colonies" of several hundred to over a thousand individuals in May.^[5] They give birth to a single pup.^[5]

The Yaeyama little horseshoe bat is classed as Endangered on the IUCN Red List.^[1] The principal threats are deforestation and habitat loss, destruction of their roosts, and disturbance by tourists.^[5]