Japanese long-eared bat

It was described as a new species in 1908 by American zoologist Glover Morrill Allen. The holotype had been collected in December 1906 by Alan Owston on Mount Fuji. Allen received the specimen from Thomas Barbour. Allen noted that it resembled the brown long-eared bat, Plecotus auritus.[3] Its species name "sacrimontis" is from Latin sacer meaning "sacred" and mons meaning "mountain."[4]

In 1929, Nikolay Alekseyevich Bobrinski published that he considered P. sacrimontis as a synonym of P. auritus. In 1938, Allen himself expressed doubts about P. sacrimontis as a species, saying "Bobrinski...is very likely right in believing the name a synonym of P. auritus."[5] In 1942, George Henry Hamilton Tate published that he considered P. sacrimontis as a subspecies of P. auritus, with a trinomen of P. auritus sacrimontis.[6] This was largely maintained until 2006, when Spitzenberger et al. revised the genus Plecotus. They found that P. sacrimontis had a high genetic distance from other Plecotus species, and thus determined that it should be considered a full species rather than a subspecies of P. auritus.[7]

It has woolly fur and a "mask" of darker fur on its face.[7]

Its range includes several islands of Japan, including Hokkaido, Honshu, Shikoku, Rebun, and Rishiri. It is also found on the Kuril Islands, specifically Iturup and Kunashir.[1] It has been documented at a range of elevations from 700–1,700 m (2,300–5,600 ft) above sea level.[1]

As of 2019, it is evaluated as a least-concern species by the IUCN. It meets the criteria for this classification because its geographic range is relatively large; it is found in a variety of habitats; and no major threats to its existence are known.[1]