Rhinolophus affinis Horsfield, 1823

Suyanto, Agustinus & Struebig, Matthew J., 2007, Bats of the Sangkulirang limestone karst formations, East Kalimantan - a priority region for Bornean bat conservation, Acta Chiropterologica 9 (1), pp. 67-95 : 84-85

Rhinolophus affinis Horsfield, 1823

Intermediate horseshoe bat

New material

6♂♂ ( MZB M26773 / 26776 / 26777 / 26782 / 26783 / 26797 ); 2♀♀ ( MZB M26750 / 26356 ) .

Records from Borneo

Sabah: Bundu Tuhan (USNM); Sara- wak: Kuching, Samunsam ( Payne et al., 2000); Gunung Penrisen (Jayaraj et al., 2006). WestKal: Betung Kerihun NP (Hariuchi 1999); Sungai Pangkalahan ( Payne et al., 2000). SouthKal: Sungai Pasir ( Payne et al., 2000). EastKal: Gunung Kombeng, Liang Lusan cave ( Yasuma, 1994); Labanan (Inhutani logging concession) (MZB); Sun- gai Lesan PF (M. J. Struebig, unpublished data); Gunung Limut (A. Suyanto, unpub- lished data).

Comments

This species was captured in harp-traps at all formations except Tintang and was particularly abundant. Its presence was con- firmed at Gua Sungai in Marang. Rhinolo- phus affinis in Borneo is otherwise only known from a few localities in Sarawak, West and South Kalimantan ( Payne et al., 2000). However, it appears that some re- searchers may have misidentified this species as R. arcuatus based on forearm length alone. Payne et al. (2000) note that in Borneo R. affinis can be distinguished from R. arcuatus by the shape of the connecting process, which in R. affinis originates below

the tip of the sella forming a slight notch or lip. In R. arcuatus , the connecting process is arcuate, forming a semicircle (Csorba et al., 2003).

Measurements listed by Payne et al. (2000) were actually from Peninsular Ma- laysia specimens for R. affinis (FA 49–54 mm, body mass 12.5 g) and from two spec- imens of R. arcuatus from Sarawak (46–49 mm). Csorba et al. (2003) state that affinis is usually larger, but list overlap in the fore- arm lengths for the two species ( arcuatus 42.0– 53.5 mm; affinis 46.0– 55.5 mm) over their respective ranges. Specimens collect- ed during this study were typically smaller in forearm length (46.5–48.8 mm) than those listed by Payne et al. (2000) from Peninsular Malaysia, but were confirmed as R. affinis by the shape of the connecting process and dentition based on comparative material from Myanmar in the HZM. Based on examination of the noseleaves of speci- mens listed as R. arcuatus in the MZB and Universitas Mulawarman Samarinda, we suggest that these specimens are also R. af- finis, a pattern that may emerge if other Bornean ‘ arcuatus ’ specimens are re-exam- ined. Cranially, we note the large size of the upper canine in Kalimantan specimens, but have been unable to compare to the type se- ries of arcuatus or to other affinis specimens from Borneo. Further study of these horse- shoe bats is recommended to fully under- stand their taxonomy in the region.