Great Evening Bat Ia io (Vespertilionidae, Chiroptera) from the Pleistocene of Vietnam (Lang Trang Cave)

Abstract—A dentary fragment of a great evening bat Ia io Thomas, 1902 found in 2020 in the Pleistocene deposits of the Lang Trang karstic cave in northern Vietnam is described. This rare species of large tropical bats now inhabits Nepal, eastern India, southern China, Thailand, Laos, and Vietnam and as a fossil is known from the Pleistocene of China. In Vietnam the fossil remains of this species have been discovered for the first time. By the total size and lower molar structure, the specimen from the Lang Trang cave is most similar to the subspecies Ia io peninsulata Soisook et al., 2017 that now occurs in southern Thailand.