Pipistrellus affinis ( Dobson, 1871 )

Bates, Paul J. J., Nwe, Tin, Bu, Si Si Hla, Mie, Khin Mie, Swe, Khin Maung, Nyo, Nyo, Khaing, Aye Aye, Aye, Nu Nu, Toke, Yin Yin, Aung, Naing Naing, Thi, Mar Mar & Mackie, Iain, 2005, A review of the genera Myotis, Ia, Pipistrellus, Hypsugo, and Arielulus (Chiroptera: Vespertilionidae) from Myanmar (Burma), including three species new to the country, Acta Chiropterologica 7 (2), pp. 205-236 : 230

Pipistrellus affinis ( Dobson, 1871)

Chocolate Pipistrelle

Vesperugo (Pipistrellus affinis) Dobson, 1871: 213 ; Bhamo, north-eastern Burma ( Myanmar)

New material from Myanmar

Mon State: Saddan Sin Cave, 30.10. 2002, 1 ♂ (H3); Indian Single Rock Temple Cave, 19.11.2002, 1 ♂ (H22) .

Previous records from Myanmar

Kachin State: Bhamo (type locality of affinis ).

Descriptive characters

With a forearm length of 36.8, 37.3 mm based on two specimens from Myanmar ( Table 4) (FA = 38.4–41.4 mm in Bates and Harrison, 1997), this is a medium- large species of pipistrelle. The pelage is soft and long. The hairs on the dorsal surface are dark brown, almost black, with the extreme tips of some the hairs pale grey-brown, giving a grizzled effect. The hairs on the ventral surface are almost white at the base but with dark tips; those nearest the anus are white throughout their length. The baculum, which is 3.3–3.4 mm in length, is broad, proximally widened and ventrally deeply fluted, with no distal expansion ( Fig. 1G ). In the skull, the rostrum is broad with median and lateral depressions. The brain- case is low and the zygomata, which are also robust have low but distinct postorbital processes. The first upper premolar (P2) is of moderate size, about two-thirds the crown area of the first upper incisor (I2); it is situated in the toothrow or slightly dis- placed internally. The first lower premolar (P2) is situated in the toothrow, its crown

area about half to two-thirds that of the sec- ond (P4).

Similar species

The distinctive shape of the baculum distinguishes P. affinis from all other local pipistrelle species. In comparison to the skull of P. ceylonicus , the zygomata are more robust; the rostrum is broader than that of P. pulveratus ; unlike P. joffrei , the fifth digit is not reduced; and un- like A. circumdatus , the second upper incisor (I3) is half or more the height of the first (I2).

Taxonomic notes

The bacula of the two specimens of P. affinis differ in some morphological aspects from the baculum of a specimen referred to P. affinis from Wynaard in India, which is illustrated in Hill and Harrison (1987: Fig. 8a). The shaft of the Myanmar specimen is narrower, the tip has a much less distinct concavity and the base is deeper when viewed laterally ( Fig. 1G ). Possibly the specimens belong to different taxa. Unfortunately, the holotype of P. affinis from Kachin State, Myanmar does not have a baculum.

Ecology

A single male specimen was collected in Saddan Sin Cave, which is situated in a large isolated limestone outcrop set amongst extensive paddy fields and many toddy palms. Two specimens were taken from Indian Single Rock Temple Cave, which is in a well cultivated former floodplain with a number of large, tree-covered limestone outcrops. Evergreen, deciduous and mangrove forests are found in the area. Bhamo, the type locality of the species, is a small city situated adjacent to the Ayeyarwady River and is surrounded by deciduous and evergreen forest.

Figures

FIG. 1. Bacula of nine species of Pipistrellus, Arielulus and Ia. Lateral (above) and dorsal (below) views of: A — P. ceylonicus. HZM.3.31458, Sri Lanka; B — P. coromandra. MN2 (HZM.9.35441), Myanmar; C — P. tenuis. MV14 (HZM.11.35444), Myanmar; D — P. pulveratus. BD14, Myanmar; E — P. lophurus. After Hill and Harrison (1987); F — P. cadornae. HZM.3.32165, Vietnam; G — P. affinis. H22 (HZM.2.35125), Myanmar; H — A. circumdatus. After Hill and Harrison (1987); I — I. io. HZM.4.32150, Vietnam. Scale = 2 mm