Cynopterus brachyotis (Müller, 1838)

Huang, Joe Chun-Chia, Jazdzyk, Elly Lestari, Nusalawo, Meyner, Maryanto, Ibnu, Maharadatunkamsi, Wiantoro, Sigit & Kingston, Tigga, 2014, A recent bat survey reveals Bukit Barisan Selatan Landscape as a chiropteran diversity hotspot in Sumatra, Acta Chiropterologica 16 (2), pp. 413-449 : 419

Cynopterus brachyotis (Müller, 1838)

Lesser short-nosed fruit bat

New records

Lampung Province: Kuyung Arang Village, Lombok Village, Sidodadi Village, Sukabanjar Village, Sukaraja Forest, Sukaraja Village, Sumberjaya Village, Sumber Rejo Village.

New material

Six individuals were collected as voucher specimens. Lampung Province: Sumberjaya Village, 1♀ ( MZB 34971); Sumber Rejo Village, 4♂♂, 1♀ ( MZB 34956, 34958, 34973, 34974, 35806).

Previous records from Sumatra

Throughout Sumatra (see detailed localities in Kitchener and Maharadatunkamsi, 1991).

Remarks

In our study area, the C. brachyotis- like bats exhibit two distinct morphological forms. One has ears with a straight or slightly notched posterior edge, and has a larger body size; the ears of the other morph have a curved margin to the posterior edge and body size is smaller ( Table 2 ). The two morphs also differed in habitat use; whereas the larger morph was usually abundant in disturbed habitats but rare within forested habitats, the capture rate of the small morph was generally high in all surveyed habitats. Notably, in contrast to the irritable and noisy behaviors of other Cynopterus species, most individuals of the small Cynopterus were generally calm and silent either in nets or during processing.

Campbell et al. (2004) described five cytochrome b lineages of C. brachyotis complex in South and Southeast Asia, two of which were from the Sunda Shelf and described as Forest and Sunda lineages. The two Sunda Shelf C. brachyotis lineages also differ in body size and habitat use; C. brachyotis Forest lineage has a smaller forearm length (FA = 54.3–63.7 mm) and is associated with forest, contrasting with the larger C. brachyotis Sunda lineage (FA = 60.0–70.0 mm) associated with disturbed habitats. Nevertheless, the authors did not assign either to C. brachyotis because they were not able to make comparisons with type material ( Campbell et al., 2004). Three following publications ( Abdullah and Jayaraj, 2006; Jayaraj et al., 2012; Fong et al., 2013) confirmed the presence of two distinct morphs of ‘ C. brachyotis ’ in Malaysia and their ecological preferences in habitat. By a preliminary morphological comparison with the holotype of C. brachyotis, Abdullah and Jayaraj (2006) further suggested that Malaysia’s large morph was the nominate species and the small form is a different species. Interestingly, C. minutus , which was first described from the Mentawai Islands off the west coast of Sumatra, is similar in body size to the small forest C. brachyotis of Malaysia. Cynopterus minutus is commonly found on all the Greater Sunda Islands and is frequently sympatric with C. brachyotis ( Kitchener and Maharadatunkamsi, 1991) . Unlike the two Malaysian lineages, Kitchener and Maharadatunkamsi (1991) reported overlap in radius length of C. minutus (52.9–61.9 mm) and C. brachyotis (54.7–66.7 mm) in Indonesia. However, the authors included juveniles and subadults in their samples ( Kitchener and Maharadatunkamsi, 1991), which may have smaller forearm lengths ( Elangovan et al., 2003). The taxonomic relationship between C. minutus and the small forest C. brachyotis remains unclear.

Given the above, we regard the two morphs of C. brachyotis- like bats in our study as different species, and assign the large morph to C. brachyotis (as C. brachyotis Sunda in Campbell et al., 2004 ). Our samples of the small round-eared Cynopterus are comparable in forearm length (56.5–61.6 mm, x = 57.2 mm) to both C. minutus (52.9–61.9 mm, x = 57.5 mm — Kitchener and Maharadatunkamsi, 1991) and C. brachyotis Forest (54.3–63.7 mm, x = 58.1 mm — Campbell et al., 2004), and C. cf. brachyotis Forest ( Jayaraj et al., 2012). Similar to C. minutus in using both primary forest and disturbed habitats ( IUCN, 2013), the small Cynopterus from BBSL is also a habitat generalist, which differs from C. brachyotis Forest , a forest specialist ( Campbell et al., 2004; Abdullah and Jayaraj, 2006; Jayaraj et al., 2012). Although the previous studies do not provide for comparisons of behavior and ear shape in C. minutus and C. brachyotis Forest , we tentatively regard the small form as C. minutus based on similarities of body size and habitat use.

Cynopterus brachyotis (the large form) was the most abundant pteropodid species in the study area. Capture rates were usually high in coffee plantations, forest edges and river habitats but low within forests. In our study area, C. brachyotis can be distinguished from C. sphinx by shorter ears (<18.0 mm in C. brachyotis and> 18.0 mm in C. sphinx ) and from C. horsfieldii by the absence of peg-like cusps on the lower cheek teeth and ear shape (straight or slightly notched at posterior edge in C. brachyotis , strongly notched in C. horsfieldii ).