Fig 1
Fig 2
Fig 3
Fig 4
|
Order : CHIROPTERA
Family : Rhinolophidae
Species : Rhinolophus affinis
Forearm Length : up to
5.4 cm
Weight : up to 20 grams
Source : Francis (2019)
Rhinolophus affinis
(Intermediate Horseshoe Bat) is a widespread forest-dweller which occurs in
mainland Southeast Asia (Myanmar, Thailand, Laos, Cambodia, Vietnam,
Peninsular Malaysia), insular Southeast Asia (Sumatra, Java, Borneo), and
elsewhere (parts of Bangladesh, India, Nepal, Bhutan and China) (Furey et al,
2019).
Furey et al (2019) also list this species as extant in
Singapore, however it is not listed by Baker & Lim (2012) or Davison et
al (2024). It is unlikely the species occurs in Singapore, unless it remains
undetected on islands in the northeast of the republic.
This species is known to roost in caves, and to forage within lowland forest
of various types, including disturbed forest (Francis, 2019). The examples
shown here were encountered at the disturbed margin of logged, primary
lowland forest in northern Peninsular Malaysia. Researchers at Krau Wildlife
Reserve have also netted the species in tall forest at
canopy level (Kingston et al, 2006).
Its upperparts are brown to reddish-brown, with paler underparts. The ears
and noseleaf are relatively large; the latter is relatively simple in design
with no lateral lappets, a slightly concave sella, a rounded connecting
process and a broad anterior noseleaf (Kingston et al, 2006). 'The lancet is
tall, triangular and with straight sides' (Francis, 2019). Such small-scale
anatomical features are used by researchers and biodiversity surveyors to
distinguish between different species of Rhinolophus.
Rhinolophus affinis is slightly larger than the closely-related Rhinolophus
stheno (Lesser Brown Horseshoe Bat).
The constant-frequency (CF) ultrasonic call of the bats shown here average
76 kHz, which confidently confirms the species as Rhinolophus affinis.
Kingston et al (2006) report a CF call of 78 KHz at Krau Wildlife Reserve
further south in Peninsular Malaysia.
Figs 1 and 2 : Two examples from Perak, northern Peninsular Malaysia,
foraging at dusk.
Fig 3 : Walking trail in degraded, lowland primary forest; such 'corridors'
allow Rhinolophus affinis and other forest bats to navigate through
cluttered vegetation with ease.
Fig 4 : Ultrasonic sonogram recorded at dusk. Constant frequency (CF)
in this example averages 76 KHz.
References :
Baker, N. & K. Lim, (Vertebrate Study Group, Nature Society Singapore),
2012 (Reprint). Wild Animals Of Singapore. Draco Publishing and Distribution
Pte. Ltd.
Davison, G. W. H., Gan, J. W. M., Huang, D., Hwang, W. S., Lum S. K. Y.,
Yeo, D. C. J. (eds.). 2024. The Singapore Red Data Book. Third edition.
National Parks Board, Singapore.
Francis, C.M. 2019. A Field Guide to the Mammals of South-east Asia. Second
Edition. New Holland. 416 pp.
Furey, N., Walston, J., Kingston, T. & Hutson, A.M. 2020. Rhinolophus
affinis. The IUCN Red List of Threatened Species 2020: e.T19522A21982358
Kingston, T., Lim B.L., Zubaid, A., 2006. Bats of Krau Wildlife
Reserve. Universiti Kebangsaan Malaysia.
|
