(BrÜnnich, 1782)
Indian Flying Fox
External characters (Table 3)
This is a very large fruit bat with an average forearm length of 168.4 mm (152-183 mm) (excluding specimens from the Maldives). It exceeds in size all other species known from the peninsula, except P. vampyrus which is thought to be a seasonal migrant to the Nicobar and Andaman Islands (Andersen, 1912). The snout is long and hairy throughout; it has two well developed nostrils (BW2b). The ears are black, virtually hairless, tall and pointed; they reach the back of the eye when laid forwards. The wings are massive; they arise from the sides of the dorsum and consequently there is a narrowing of the dorsal pelage. The first digit (thumb) has a large claw; the claw of the second digit is small. The feet are large and have very robust claws. The pelage is moderately long and coarse over the head, upper shoulders and ventral aspect. It is a rich chestnut brown on the crown of the head. On the nape of the neck and mantle, it varies from a light yellowish tan (PG2) to a deep chestnut brown (PG1) which is scarcely paler than the belly. It is relatively darker around the eyes and mouth. The pelage on the posterior shoulders and mid-dorsal region is short, sparse and black, with some paler hair tips. There is a clear line of demarcation on the shoulders between the chestnut hairs of the head, neck and mantle and the dark hairs of the dorsum. The hairs on the belly are most variable in colour, apparently independent of sex, age or season, ranging from pale tan to a deep orange-red (PG1) or chestnut brown. The interfemoral membrane is little developed and there is no external tail. The baculum is large and semicircular, enclosing a heart-shaped space (Fig. 8). The ventral surface is concave; it is broad distally and sometimes has a median projection. The proximal end is slightly curved dorsally forming a notch on the base; the proximal ends are situated close to each other (Agrawal and Sinha, 1973).
Karyology
2N=38, with 10 pairs of metacentrics, 4 pairs of submetacentrics and 4 pairs of subtelocentrics. The X chromosome is subtelocentric and the Y chromosome a minute metacentric (Datta, 1977). However, according to Bhatnagar and Srivastava, 1974, the X is a medium-sized somatic chromosome and the Y a telocentric chromosome.
Cranial characters
The skull is large (PG6), robust and with a long rostrum; condylobasal length averages 69.9 mm (65.9-74.9 mm) (excluding specimens from the Maldives). The postorbital processes are well developed and in some specimens may join the orbital process of each zygoma to form a complete ring; this is especially prevalent in individuals of P. g. ariel from the Maldives. The zygomata are robust in older adults; they are widest posteriorly. The postorbital constriction appears to be rather variable in breadth; it is extremely narrow in some specimens, clearly less than the interorbital width, whilst in others it is subequal to it. The sagittal crest is present but relatively weak. The palate is long; it is widest opposite m1 and the post-dental extension is well developed. The tympanic bullae are represented by a simple bony ring on each side of the broad basiocciput. The basicranial axis is at an obtuse angle to the basifacial axis. The occipital region is subtubular, but the lambda usually still forms the most posterior part of the skull. The mandible is robust but without special features.
Dentition
- The upper toothrow (C-M2) averages 27.0 mm (24.5-29.0 mm) in length (excluding specimens from the Maldives). The first (I2) and second (I3) incisors are approximately equal in size, situated adjacent to one another in a subcircular curve. The upper canine is massive with a well developed groove on its anterior surface; this is not always visible in worn teeth. The first upper premolar (PM2) is minute, less than half the height of the cingulum of the canine; it is sometimes absent. The cheekteeth have a simple structure comprised of an elevated outer and inner ridge and a central valley between these two cusps; the posterior basal ridge is virtually obsolete. M2 is reduced, usually less than a third of the crown area of M1.
- In the mandibular dentition, the second incisor (i2) exceeds the first (i1) in size. The first premolar (pm2) is small but much more developed than that of the upper (pm2). m3 is less than half the crown area of m2.
Variation
Specimens from the Indian peninsula, excluding the Himalayas are referable to P. g. giganteus . Those from the Himalayan region, Kashmir through to Assam and south to Manipur are provisionally assigned to P. g. leucocephalus on account of their longer, softer fur on the belly, back and mantle. However, the status and geographical limits of this taxon are still uncertain. Specimens from the Maldives are referred to P. g. ariel ; they are smaller with a relatively broad rostrum and heavier dentition (Table 3). In general, specimens from throughout the subcontinent, even those located in the same colony, exhibit considerable individual variation, both in size and pelage colour.
Taxonomic remarks
Corbet and Hill, 1992 suggested that P. giganteus may prove to be conspecific with P. vampyrus . If so, vampyrus is the prior name and specimens from the Indian subcontinent would be referable to P. vampyrus giganteus , P. v. leucocephalus and P. v. ariel.