Pipistrellus stenopterus

Pipistrellus stenopterus (Dobson, 1875)

Narrow-winged pipistelle

Vesperugo stenopterus Dobson 1875: 470; Sarawak, Borneo.

New Material

PSU-M 05.2 (field no. SB030508.6), ♂, 8 May 2003, Ai-kading stream, Bala Forest, Hala-Bala Wildlife Sanctuary, Wang Dis- trict, Narathiwat Province, 05°48’9”N, 101°49’15”E, collected by S. Bumrungsri and members of the Hala-Bala bat research team.

Taxonomic Notes

This is a large and robust pipistrelle bat. The specimen from Thailand has a forearm length of 38.7 mm (Table 4). Its pelage is dark brown (based on the wet specimen). In the wing, the fifth metacarpal (32.2 mm) is noticeably shorter than the fourth (36.9 mm). The ears are fleshy; each has a clubshaped tragus, which is expanded in the middle. The feet are large, longer than half the tibia length. The skull is robust with a flattened rostrum and a large nasal notch. The zygomata are slender and fragile. A sagittal crest is present and the lambdoid crests are well developed. The anterior palatal emagination extends posteriorly to the level of the front of the second premolar (P 4). The first upper premolar (P 2) is reduced, intruded from the toothrow, and compressed in a recess between the canine

(C 1) and P 4. The lower premolars are com- pressed; the first (P 2), which is 1.5 times larger in crown area than the second (P 4), is slightly extruded, its tip does not point ver- tically upwards but obliquely outwards. Over the years, this species has been vari- ously referred to the genus Nyctalus as well as Pipistrellus (for comments, see Corbet and Hill, 1992 and Simmons, 2005).

Distribution and Ecological Notes

Recorded from Borneo, Sumatra, Ma- laysia, Riau Island and Singapore (Corbet and Hill, 1992), and Mindanao Island (Koopman, 1993). This is the first record for Thailand.

In Bala Forest, a single individual was caught in the early evening (ca. 19:00h) in a mist net set about 5 m above the surface of a running stream. The stream, which was about 15 m wide, flowed through a valley of pristine lowland forest. In Malaysia, it is thought to be a gregarious species and is commonly found roosting in hollow trees or the roofs of houses (Medway, 1969).