(Kuhl, 1819)
Schreibers' Long-fingered bat
External characters (Table 108)
This is a medium-sized Vespertilionid bat with an average forearm length of 47.0 mm (44.7-49.6 mm) (Msc1). The tail, interfemoral membrane and hind limbs are long. Each wing is characterised by a highly developed second phalanx of the third finger (38.1 mm, 36.0-40.1 mm) which is approximately three times the length of the first phalanx. The membranes are uniformly dark. The pelage is soft, silky and dark throughout. The dorsal surface is a rich russet brown in some individuals, in others it is a deeper blackish brown. The ventral surface is usually slightly paler with a greyer tinge. The short dense pelage of the forehead extends to the nostril pads. The cheeks are naked below the eyes; the ears small, each with broadly rounded tip which scarcely projects above pelage of crown (Msc2). The tragus is half the height of the pinna, slightly curved forward (Msc5); the antitragus is low and ill defined (Fig. 241). The body is usually inundated with numerous ecto-parasites, especially Nycteribiids; Streblids are also found (Msc1) ( Phillips, 1980).
Cranial characters
The skull (Fig. 242) has an average condylo-canine length of 14.1 mm (13.6-14.8 mm). It is characterised by the marked inflation of the braincase anteriorly which is abruptly elevated above the low, flattened rostrum. The rostrum is tapered anteriorly, its dorsal surface flattened but with a distinct median concavity. The nasal aperture is well developed, its posterior margin about level with the back of the canines. The zygomatic arches are short and slender. The lambdoid crests are distinct laterally but absent over the lambda, which is subequal in height with the anterior braincase. There is virtually no postdental extension of the palate but there is a prominent median posterior palatal spine. The infraorbital foramina are situated far forward. The mandible is slender; the coronoid process of each half is reduced and is almost on a level with the condyle.
Dentition
- Upper toothrow length (C-M3) averages 6.1 mm (5.8-6.3 mm). The first upper incisor (I2) has a weak postero-internal secondary cusp. The second incisor (I3) is flattened, its cingulum forming a minute postero-external cusp (Fig. 243). The upper canine is tall and slender, greatly exceeding the second upper premolar (PM4) in height. The first upper premolar (PM2) is unusually large and situated in the toothrow; its crown is broadly triangular and its postero-medial base noticeably expanded. PM4 has a well defined antero-medial cingular cusp and a feeble antero-lateral one. M1 and M2 are emarginated posteriorly and have deep pits between the metacones, paracones and protocones. M3 is more than half the crown area of M2 with the metacone and third commissure well developed.
- The lower incisors are trilobate; the third incisor (i3) is distinctly larger. The cingulum of the tall and slender canine forms an antero-medial cusp above i3. The first lower premolar (pm2) is subequal in crown area to the second (pm3); the posterior premolar (pm4) is three-quarters the height of the canine. The talonids of m1 and m2 slightly exceed their respective trigonids in size. The talonid of m3 is only a little reduced.
Karyology
2N= 46 FN= 54 based on specimens from Mahabaleshwar. The autosomal set consists of two pairs of metacentrics, which are at the same time the largest autosomes; one pair of submetacentrics and a very small pair of biarmed elements; there are also 18 pairs of acrocentrics. Most of them bear one short terminal arm. Among them is a small pair with secondary constriction. The X chromosome is a medium sized submetacentric, while the Y chromosome is a smaller acrocentric (Dulic, 1980).
Variation
Specimens from the Indian subcontinent are referable to the taxon fuliginosus . This was considered a distinct species by Maeda, 1982 but is generally referred to M. schreibersii as a valid subspecies ranging from Afghanistan to China and Japan (Hill, 1983).