451.

Yanbaru Whiskered Myotis

Myotis yanbarensis

French: Murin du Yanbaru / German: Yanbaru-Mausohr / Spanish: Ratonero bigotudo de Yanbaru

Other common names: Yanbaru Myotis

Taxonomy. Myotis yanbarensis Maeda & Matsumura, 1998,

upper stream of Funga River, Aha, Kunigami-mura, Okinawajima, Japan.

Subgenus Myotis; montivagus species group. Most recent phylogenetic studies, including comprehensive taxon sampling, found M. yanbarensis to be sister to a newly described species (sp. 2 or M. secundus) from Taiwan in a strongly supported clade including M. pruinosus and representatives of the montivagus species group. Monotypic.

Distribution. Endemic to S Japan, found in Ryukyu Is (Okinawajima, Amami-Oshima, and Tokunoshima).

Descriptive notes. Head-body 36- 5—44 mm, tail 39-46 mm, ear 13-5—14- 5 mm, hindfoot 7- 5-8 mm, forearm 35-38 mm; weight 4-8 g. Fur is very soft and silky. Dorsal hairs are black, with dull silvery metallic tips. Underparts are black, with pale brown tips. Membranes and ears are black. Hairs on ventral side of uropatagium are sparse and short; dorsal surface and endopatagium are naked. Wing membrane attaches at base of first toe. Anterior border of ear turns outward; posterior border is concave at center. Tragus is ¢. 7 mm long and slender and tapers gradually toward pointed tip; its distal one-third bends externally very slightly oris straight. Skull is large as a whole, with relatively small braincase in length and width. Rostrum is long. Relative zygomatic width to condylo-basal length is large. P* and P, are the same size as last premolar. Condylobasal lengths of type specimens were 14- 5 mm (holotype) and 14- 2 mm (paratype), and maxillary tooth rows were 6 mm (holotype) and 5-9 mm (paratype).

Habitat. Evergreen broadleaf forest. The Yanbaru Whiskered Myotis is restricted to small fragments of intact mature forest on each island, and it has not been captured during surveys in other forest patches.

Food and Feeding. No information.

Breeding. No information.

Activity patterns. The Yanbaru Whiskered Myotis is nocturnal. It roosts primarily in tree hollows—the only bat species known to do so on Okinawajima.

Movements, Home range and Social organization. The Yanbaru Whiskered Myotis occurs at low densities where surveys have been conducted. Predation by the spider Nephila pilipes has been reported.

Status and Conservation. Classified as Critically Endangered on The IUCN Red List. The Yanbaru Whiskered Myotis is restricted to severely fragmented forest patches on three islands, extent of occurrence is less than 100 km? and extent and quality of habitat continues to decline due to deforestation. It occurs on the US military base on Okinawajima and in a forest reserve on Amami-Oshima. It was captured on Okinawajima in April 2018 for the first time since its discovery 22 years ago. Additional surveys are needed to clarify risk of local extirpation.

Bibliography. Abe et al. (2005), Amador et al. (2018), Kawai et al. (2003), Kyoto University (2018), Maeda (20089), Maeda & Matsumura (1998), Ministry of the Environment (2007), Ohdachi et al. (2009), Ruedi, Csorba et al. (2015), Ruedi, Stadelmann et al. (2013), Simmons (2005).