Ryukyu tube-nosed bat

The Ryukyu tube-nosed bat (Murina ryukyuana) is a small, plant-roosting species of bat in the family Vespertilionidae. It is endemic to three islands of the central Ryukyus (Okinawa, Tokunoshima, and Amami-Ōshima) and is listed as Endangered by both the IUCN and Japan's Ministry of the Environment.^[1][2]

Ryukyu tube-nosed bat
Conservation status
Endangered  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Chiroptera
Family:	Vespertilionidae
Genus:	Murina
Species:	M. ryukyuana
Binomial name
Murina ryukyuana Maeda & Matsumura, 1998

Taxonomy and etymology

Murina ryukyuana was described in 1998 based on specimens from northern Okinawa.^[3] Its specific epithet refers to the Ryukyu Archipelago.

Description

Murina ryukyana has rounded ears that are 35.5 to 37 mm (1.40 to 1.46 in) with tragi that are 9.5 to 10.5 mm (0.37 to 0.41 in). It has straight hair in shades of brown, with dorsal hairs longer than its ventral hairs.^[3]

Distribution and habitat

The bat is found only in the subtropical evergreen broad-leaf forests of Okinawa Island, Tokunoshima, and Amami-Ōshima.

Ecology and behavior

Roosting

Radio-tracking reveals strong reliance on plant roosts throughout the year.^[4] Non-reproductive individuals usually roost singly, mainly in understory foliage. Maternity roosts occur both in foliage roosts and small tree cavities, but are more likely to occur in older forest stands and tend to be higher off the ground. Roost switching is frequent (mean stay 1.6 days), and the maximum roost-switch distance recorded is 179 m.

Foraging and diet

Although its diet has not been analyzed, morphology and very faint, steep frequency-modulated echolocation calls (peak ≈ 60 kHz) suggest prey capture by gleaning or short-range hawking inside clutter.

Social calls have been recorded far more often than feeding buzzes, indicating a possibly important communicative repertoire and either greater reliance on listening for prey or very soft feeding buzzes.

Reproduction

Pregnant females have been captured from late April to early July.^[4] Maternity colonies of 2–15 (maximum 16) individuals persist until at least November.

Echolocation

Search-phase calls are short FM sweeps with peak frequency 61.5士4.67 kHz on Amami-Ōshima and 59.9士6.61 kHz on Tokunoshima.^[5]

Conservation

Status and threats

Forest loss is the primary threat. Old-growth stands may be particularly important because of their seeming importance for maternity colonies.^[4] Understory foliage removal may reduce the roosting habitat of this species or harm roosting individuals.

Recommended actions

Since other threats have not been identified, forest protection is the primary conservation method recommended. Where pure forest preservation is not possible, the following approaches are recommended to mitigate the potential impacts of timber harvesting: (1) retaining understory vegetation, (2) preserving trees along streams, (3) maintaining high cavity densities by protecting old trees and snags, and (4) avoiding tree removal between April and July (pupping season).^[4]