Black-Gilded Pipistrelles (Arielulus s.str., Vespertilionidae, Chiroptera) in Eastern Indochina

The available information on records of the black-gilded pipistrelle, Arielulus circumdatus sensu lato, in eastern Indochina was examined, and suggestions were made about its taxonomic position and status. The known range of this taxon spreads from Nepal to Vietnam and Java but seems to be extremely sporadic; in Vietnam, it is known from only nine locations, five of which are on the Dalat Plateau and neighboring Hon Ba Mountain. All records are confined to mountain forests at altitudes from 800 to 2200 m a.s.l. Analysis of the sequences of the cytb and COI mitochondrial genes showed that Arielulus specimen from northern Vietnam (Tay Con Linh) formed a common clade with a specimen from Nepal but showed about 12–13% differences in each of the genes from the A. circumdatus from south and central Vietnam. Also, these northern and southern Arielulus lineages show a difference in pelage color. We believe that the northern form should be defined as a separate species, the valid name of which could be A. drungicus (Wang 1982), the form described from China. Thus, Arielulus sensu stricto is represented by two species in Vietnam, of which A. drungicus has quite a limited distribution range in the northern region. Received 27 August 2024. Accepted 28 March 2025.