Great Evening Bat

Ia io Thomas, 1902: 164; Chungyang, south Hubei, China

New material from Myanmar

Shan State: Hta Ein Cave, 18.8.2003, 1 ♂ (IL4). There are no previous records.

Descriptive characters

With a forearm length of 77.2 mm based on a single specimen from Myanmar (Table 4; FA = 70.9–77.3 mm in Bates and Harrison, 1997; 75.5–79.8 mm in Hendrichsen et al., 2001 and 70 –77.5 mm in Borissenko and Kruskop, 2003), this is the largest Ves- pertilionid bat known from the country. The pelage is a uniform dark grey-brown, almost black, on the dorsal surface. It is paler below; the hairs have dark brown roots and grey-brown tips. Unfortunately, the bacu- lum of the single male from Myanmar was damaged in preparation. In a specimen from Vietnam (HZM.4.32150), the baculum is minute and triangular in shape (Fig. 1I); the two lateral basal processes are deflected ventrally; the length is 1.4 mm and the greatest breadth 0.8 mm. With a condylocanine length of 26.7 mm, the skull is large and the rostrum is particularly robust. The second upper incisor (I3) is minute, subequal in height to the cingulum of the first incisor (I2). The first upper pre- molar (P2) is also minute, about one tenth the crown area of I2, and is displaced internally from the toothrow. The first lower premolar (P2) is half the crown area of the second (P4).

Similar species

Ia io is distinguished from all other Ves- pertilionid species in the region by its size.

Compared to the local species of Pipistrel- lus (but not A. circumdatus), the second up- per incisor (I3) is greatly reduced in com- parison to the first (I2). Ecology

Like M. mystacinus (for further details, see above), I. io was collected in a mist net set at the entrance of Hta Ein Cave.