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The dusky fruit bat (Penthetor lucasi Dobson, 1880), the only member of the genus Penthetor, a genus of megabat.

Distribution

This species was recorded from six localities, Balui ( n = 9), Tanjung Datu (n = 4), Gunung Gading (n = 14), Kubah (n = 15), Lambir (n = 5) and Samunsam (n = 1), all from Borneo. It ranges from southern Thailand, Sumatra, Peninsular Malaysia, Riau archipelago ; in Borneo from Gomantong, upper Sungai Kuamut and Sapulut in Sabah; and in Sarawak from Niah, Gunung Mulu, Sungai Sarawak (Payne et al. 1985), and Bau (Karim et al. 2004).

Biology and ecology

P. lucasi was netted in primary forest at Kubah, Lambir and Datu, in regenerated forest at Gunong Gading National Park, and in old secondary habitat at Balui and mangrove swamp at Samunsam. The specimens caught from Tanjung Datu, Sarawak were observed to be darker in fur colour than those observed elsewhere.

In May and October 1996, specimens caught at Kubah were either pregnant, lactating or in post-lactating conditions. In June a female was pregnant in Gunong Gading, and a post-lactating female was caught at Lambir in November. Males had enlarged testes in August, October and November at Samunsam, Lambir and Kubah. Immatures and subadults were netted in Lambir and Kubah in October and November, indicating that their birth occurred between August and September. Subadults (n = 3) were collected in June in an old secondary habitat at Sungai Balui in Sarawak. Medway (1978) reported large numbers of pregnant females caught in Selangor in September and a few in June. The species roosts in rock shelters or caves; and eats fruit, which it carries back to the cave (Payne et al. 1985).

Measurements

FA 57-62

T 8-13

E 14-16.5

Wt 30-44 (Francis,1985).

Identification

The upper parts of dusky fruit bats are dark grey-brown in colour. The under parts are pale buff-grey in colour. The top of its head often distinctly darker down the centre and paler near the eyes. Ears have dark edges. There is only one pair of lower incisors; outer upper incisors shorter than inner pair (Francis,1985). Penthetor lucasi can be distinguished from other members of the family Pteropodidae based on the fact that it has only one pair of lower incisors, and that a tail is present and extremely thin as compared to other Pteropodids (Nowak,1999).

P. lucasi lacks facial features related to echolocation, such as a nose leaf or enlarged tragus. The eyes are large to account for a greater dependence on vision than seen in microchiropterans. It has a well-developed postorbital process and a claw on the second digit with the second finger being independent. The palate extends beyond the last upper molar and has ridges (Feldhamer et al.,1999).

Similar species

Short-nosed fruit bats, Cynopterus spp., are brighter-coloured with two pairs of lower incisors; tailless fruit bats, Imegaerops spp., lack a tail, have broader, higher nostrils, light brown fur with pale grey basses, and small, even upper incisors (Francis,1985).

Ecology and habitat

The dusky fruit bat is irregularly distributed throughout lowland and hill forests (Nowak,1999). It roosts in colonies in rock shelters or caves, sometimes in near-total darkness (Francis,1985).

Reproduction

Research indicates that breeding in P. lucasi is seasonal. One study of pregnancy in P. lucasi revealed that the highest number of pregnant females were recorded in September, very few females were pregnant in June, and there were no recorded pregnancies in January, February, March, and July (Nowak,1999). There is typically only one offspring in a birth (Nowak,1999).

Behavior

This species appears to be gregarious, roosting in large groups (Nowak,1999). P. lucasi roosts in caves, rock shelters, and in the nooks and crannies between boulders, a habit that likely limits its distribution (Nowak,1999). Unlike the suborder Microchiroptera, members of the Megachiroptera, such as P. lucasi do not echolocate. They rely on vision and olfaction to navigate and locate food (Feldhamer et al.,1999)

Food Habits

The dusky fruit bat is a frugivore. It emerges from its roost at dusk to feed at the nearest food source, often a fruit plantation (Nowak,1999). Food sources are located primarily through olfaction (Feldhamer et al.,1999).

Economic Importance for Humans: Negative

Dusky fruit bats feed at the fruit source nearest to their roost, which is often a fruit plantation. In areas where the population density of these bats is high, they can cause considerable damage to crops (Feldhamer et al.,1999).

Economic Importance for Humans: Positive

As a frugivore, P. lucasi may provide a valuable ecological service to humans in the dispersal of seeds of the plants they consume away from the parent tree, either through spitting the seeds out or passing them through the gut (Feldhamer et al.,1999).

Distribution and status

South-East Asia: Peninsular Malaysia and extreme South Thailand. Also Borneo, Sumatra and Riau archipelago. Not currently at risk, through uncommon in most areas (Francis,1985).

References

• Mohd Ridwan ABD RAHMAN and Mohd Tajuddin ABDULLAH. Morphological Variation in the Dusky Fruit Bat, Penthetor lucasi, in Sarawak, Malaysia.2010.Tropical Natural History 10(2): 141-158.http://www.biology.sc.chula.ac.th/TNH/vol10%20no2.html
• Mohd Ridwan ABD RAHMAN and Mohd Tajuddin ABDULLAH. Memecahkan Kod DNA cecadu hitam pudar. "Dewan Kosmik". Jun 2011, 32-33.http://unimas.academia.edu/MohdRidwanAbdRahman/Papers/718312/Memecahkan_Kod_DNA_Cecadu_Hitam_Pudar
• Abdullah, M.T., Wong, S.F, and Besar Ketol. 2010. Catalogue of mammals of UNIMAS Zoological Museum, Universiti Malaysia Sarawak Publication, Kota Samarahan.
• Abdullah, M.T., Jusanit, P., Di, P.W.H., Zabani Ariffin, M. and Hall, L.S. 2007. Observations on bats in three national parks in Thailand. Tigerpaper. 34: 5-10.
• Abd Rahman, M.R. 2010. Biogeographical status of dusky fruit bat, Penthetor lucasi (Chiroptera: Pteropodidae) inferred by morphological and genetic analyses in Malaysia. MSc Thesis, Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, Kota Samarahan.
• Jayaraj, V.K. 2008. The phylogenetic relationship of megachiroptera in Malaysia inferred from morphological and DNA analyses, MSc Thesis. Universiti Malaysia Sarawak, Kota Samarahan,Malaysia.
• Hall LS, Gordon G. Grigg, Craig Moritz, Besar Ketol, Isa Sait, Wahab Marni and M.T. Abdullah. 2004. Biogeography of fruit bats in Southeast Asia. Sarawak Museum Journal LX(81):191-284.
• Karim, C., A.A. Tuen and M.T. Abdullah. 2004. Mammals. Sarawak Museum Journal Special Issue No. 6. 80: 221—234.
• Mohd. Azlan J., Ibnu Maryanto , Agus P. Kartono and M.T. Abdullah. 2003 Diversity, Relative Abundance and Conservation of Chiropterans in Kayan Mentarang National Park, East Kalimantan, Indonesia. Sarawak Museum Journal 79: 251-265.
• Hall LS, Richards GC, Abdullah MT. 2002. The bats of Niah National Park, Sarawak. Sarawak Museum Journal. 78: 255-282.
• Payne J., C.M. Francis, and K. Phillips. 1985. A Field Guide to the Mammals of Borneo.
• Francis, C. 1985. Field guide to the mammals of South-East Asia. Kuala lumpur: Weng Fatt Sdn. Bdn. (p. 175).
• Nowak, R. 1999. Walker's Mammals of the World, volume 1. Baltimore: The Johns Hopkins University Press. Retrieved January 16, 2009, from http://animaldiversity.ummz.umich.edu/site/accounts/information/Penthetor_lucasi.html.
• Feldhamer, G., L. Drickamer, S. Vessey, J. Merritt. 1999. Mammalogy: Adaptation, Diversity, and Ecology. Boston: McGraw Hill.

Retrieved January 16, 2009, from http://animaldiversity.ummz.umich.edu/site/accounts/information/Penthetor_lucasi.html.