Fig 1
Fig 2
Fig 3
Fig 4
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Order : CHIROPTERA
Family : Vespertilionidae
Species : Hypsugo spp.
Forearm Length :
mainland Southeast Asia species have a maximum forearm length of
3.2 to 4.1 cm.
Weight : mainland Southeast Asia species have a maximum weight of
4 to 7 grams.
As of 2024, a total of 18
species of evening bat in the family Vespertilionidae are assigned to the
genus Hypsugo. Of these, 12 are known to occur either wholly or
partly within Southeast Asia.
Many Hypsugo species are poorly known, and are rarely captured during
biodiversity
surveys. This apparent rarity may, however, be due to low sampling effort in edge and
open-space habitats which some Hypsugo prefer.
These are small bats which are differentiated from Pipistrellus
bats by their skull characteristics, dental features, reproductive
morphology and other traits which can only be determined by a detailed,
close-up inspection.
Their fur is often long and fluffy. Their ears are similar to Pipistrellus
but are often broader and wider; the tragus is short, broad, and curved
slightly forwards (Francis, 2019). Some species have pale, translucent
wings, for example H. macrotis and H. vordermanni.
Some Hypsugo have been captured in relatively open forest habitats, but many
others are known to forage over water bodies including rivers, freshwater lakes, mangrove inlets and intertidal habitats. H.
vordermanni, from Borneo, is known to feed on insects and fish in rivers and calm seas (Phillipps
& Phillipps, 2018).
Featured here (Figures 1 and 2) is the Big-eared Pipistrelle (Hypsugo macrotis), a
typical example of the genus. This rarely encountered bat is known from
Peninsular Malaysia, Singapore and parts of Indonesia, including eastern Sumatra, Bali
and Lombok. It is known to roost amongst buildings in Peninsular Malaysia
(Marina et al, 2021). In
Singapore it forages over intertidal sand and mudflats (Lee & Teo,
2018).
The potential for the discovery of new species of Hypsugo is high. In
1997 a new species was collected next to a broad, fast-flowing river in
lowland, evergreen forest in Laos; this had markedly well-developed upper
canines and was named the Long-toothed Pipistrelle (Hypsugo dolichodon).
It was formally described by Görföl et al in 2014.
Fig 1 : Part of a group of more than fifteen Big-eared Pipistrelle (Hypsugo
macrotis) known to regularly roost in a quiet corner on the first floor
of a suburban house.
Fig 2 : A single bat roosting separately to the rest.
Fig 3 : The intertidal mudflats of Chek Jawa on the island of Pulau Ubin,
Singapore, is a known foraging site for Hypsugo macrotis.
Fig 4 : A typical setting in Peninsular Malaysia; predominantly low-rise housing and
commercial buildings provide ample roosting opportunities for lowland, 'open
country' bats, with easy access to foraging sites in nearby secondary
habitats.
Thanks to Tou Jing Yi for allowing access to the bats shown here.
References :
Francis, C. M., 2019. Field Guide to the Mammals of South-east Asia. Second
Edition. Bloomsbury Publishing. 416 pp.
Görföl, T., Csorba, G., Eger, J. L., Son, N. T. & Francis, C. M.
(2014). Canines make the difference: a new species of Hypsugo (Chiroptera:
Vespertilionidae) from Laos and Vietnam. Zootaxa, 3887(2), 239-250.
Lee, Benjamin, P. Y-H., & Teo, Robert C. H. (2018). First record of the
big-eared pipistrelle in Singapore. Singapore Biodiversity Records 2018:
57-58. National University of Singapore.
Marina, M. T., Chubo, J. K., Senawi, J., Nur Farrazuin, J. & Ahmad
Badrul Amin, A. R. (2021). Current Status of Bat Diversity and Conservation
in Universiti Putra Malaysia and its Forest Reserves. Journal of
Sustainability Science and Management, 16(7), 237-259.
Phillipps Q. & Phillipps K. (2016). Phillipps’
Field Guide to the Mammals of Borneo and Their Ecology: Sabah, Sarawak,
Brunei, and Kalimantan. Second Edition. John Beaufoy Publishing. 400 pp.
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