Thoopterus nigrescens (Gray, 1870)

Don E. Wilson & Russell A. Mittermeier, 2019, Pteropodidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 16-162 : 74-75

23.

Common Swift Fruit Bat

Thoopterus nigrescens

French: Cynoptere sombre / German: Schwarzflligelflughund / Spanish: Toptérido cenizo

Other common names: Swift Fruit Bat

Taxonomy. Cynopterus marginatus var. nigrescens J. E. Gray, 1870 ,

“Morty [= Morotai] Island,” Molucca Islands, Indonesia.

This species is monotypic.

Distribution. Talaud Is (Karakelong), Sangihe Is (Sangihe), N Moluccas (Morotai), Sulawesi (including nearby Wowoni and Buton Is), and Sula Is (Taliabu, Mangole and Sanana).

Descriptive notes. Head-body 94- 111 mm, tail 6 mm (single individual), ear 13-17 mm, hindfoot 18-20 mm, forearm 70-82 mm; weight 67-99 g. Head of the Common Swift Fruit Bat has relatively long muzzle, nostrils are short and barely divergent, philtrum reaches upper lip, and lowerlip has two large and flat triangular pads. Eyes are moderately large; iris is warm brown to chocolate-brown. Ears are short and rounded. Head pelage is darker than body, moderately long, dense, and dark grayish brown, with short guard hairs on nape; dorsal pelage is long (¢. 9 mm), soft, silky, and dark grayish brown, somewhat irregularly washed in light brown especially on dorsal forearm. Uropatagium is narrow at center, with dorsal hairs extending over tibia; underside of uropatagium is naked; tail is minute, infrequently absent; and calcar is short (7-8 mm). Chest and belly fur is dark gray, occasionally silvery, and dense. Wing membranes are black from sides of body and attach to second toe; index claw is present. Skull lacks basicranial deflection, rostrum is moderately long, orbit is large with marked rim, zygomatic root is from above alveolar line, zygoma is moderately thick and strongly arched posteriorly, and braincase is domed. Dorsally, rostrum is long and slightly tapering; paranasal recesses are inflated, passing short postorbital processes posteriorly; there is no postorbital foramen; postorbital constriction is obvious; braincase is oval; sagittal crest is present but low; and nuchal crest is obvious. Ventrally, palate is flat, with diverging tooth rows; post-dental is moderately short, and sides are slightly convergent; end of post-dental palate is straight; and ectotympanic is small and wide anteriorly, narrowly edged internally by entotympanic. Mandible is moderately thick; coronoid is tall, almost vertical with wide tip; condyle is slightly above lower alveolar line; and angle is distinct and rounded. There are nine arched interdental palatal ridges, and posterior one-half is divided at middle, followed by three post-dental divided ridges, the last one is denticulate, plus a last, ill-defined ridge, denticulate, near end of post-dental palate. Dental formula for all species of Thoopterusis12/2,C1/1,P 3/3, M 1/2 (x2) = 30. Upper incisors are conical, with I longer than I*; C' is long and decurved, with anterointernal groove, longer and bulkier in males; P' is small; and posterior cheekteeth are large, decreasing in size, with squarish outline, and lingual cusps reduced. Lower incisors are small and crowded; C, 1s rather small and straight, with strong cingulum and cusp-like lobule; P, is well developed, with triangular crown; posterior cheekteeth are tall, very wide, and squarish, with reduced lingual cusp and strong surface cusp, and M, very low and peg-like. Diploid number is 2n = 38.

Habitat. [Lowland and montane primary rainforests and lightly disturbed forests from sea level up to elevations of 2400 m.

Food and Feeding. The Common Swift Fruit Bat is primarily frugivorous. There are miscellaneous records of use offig trees ( Ficus spp. , Moraceae ). Strong dentition suggests consumption of hard fruits.

Breeding. Young Common Swift Fruit Bats are present in an area year-round; two pregnant females with single embryos were recorded in January; and females with large nipples were found in January and March.

Activity patterns. No information.

Movements, Home range and Social organization. Infestation with parasites on Common Swift Fruit Bats suggests communal roosting in permanent locations, perhaps cavities or caves.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Common Swift Fruit Bat is common, even dominant, and able to adapt to disturbed forest habitats. Population trend is unknown, but most of the population not fragmented.

Bibliography. Andersen (1912b), Bergmans & Rozendaal (1988), Maryanto (2004), Maryanto et al. (2011), Mubarok et al. (2018), Ruedas, Kingston, Helgen & Sinaga (2008), Wiantoro et al. (2017).

Figures

15. Brooks's Dayak Fruit Bat (Dyacopterus brooksi), 16. Common Dayak Fruit Bat (Dyacopterus spadiceus), 17. Philippine Large-headed Fruit Bat (Dyacopterus rickarti), 18. Blanford’s Fruit Bat (Sphaerias blanfordi), 19. Bornean Spotted-winged Fruit Bat (Balionycteris maculata), 20. Malayan Spotted-winged Fruit Bat (Balionycteris seemundi), 21. Bornean Pygmy Fruit Bat (Aethalops aequalis), 22. Common Pygmy Fruit Bat (Aethalops alecto), 23. Common Swift Fruit Bat (Thoopterus nigrescens), 24. Suhaniah’s Swift Fruit Bat (Thoopterus suhaniahae), 25. Mindanao Pygmy Fruit Bat (Alionycteris paucidentata), 26. Fischer’s Pygmy Fruit Bat (Haplonycteris fischeri), 27. Luzon Pygmy Fruit Bat (Otopteropus cartilagonodus), 28. Salim Ali’s Fruit Bat (Latidens salimaliz), 29. Sundaic Black-capped Fruit Bat (Chironax melanocephalus), 30. Sulawesi Black-capped Fruit Bat (Chironax tumulus), 31. Lucas’s Short-nosed Fruit Bat (Penthetor lucasu)

Distribution. Talaud Is (Karakelong), Sangihe Is (Sangihe), N Moluccas (Morotai), Sulawesi (including nearby Wowoni and Buton Is), and Sula Is (Taliabu, Mangole and Sanana).