Temminck, 1838
Pouch-bearing bat
External characters (Table 23)
This is a medium sized species with an average forearm length of 65.5 mm (63.0-68.2 mm). Unlike T. nudiventris (Fig. 52), there is no radio-metacarpal pouch on the wing. There is a well developed gular sac in the male; it is less developed in the female. The chin and sides of the gular sac are covered with very short hairs. The lower lip has a deep narrow groove; the ears are comparatively small. The pelage on the upper body scarcely extends onto the wing membranes; posteriorly it terminates in a well defined line limited by the root of the tail; the interfemoral membrane and legs are quite naked. The pelage is usually dark brown or black on the dorsal surface. It has a mottled appearance in most specimens, with small irregular white patches (Tsa1); a minority of individuals have a uniform dark dorsal pelage. One specimen in the collection of The Natural History Museum, London is exceptionally pale being a light russet brown above and below. The underparts are usually grey brown. The hair bases are relatively pale, above and below. The membranes are almost black, although the posterior margin of each wing, between the foot and the fourth digit, may be edged in white. The wings are long and narrow and are attached to the ankles. The feet do not have the conspicuous long hairs which are present in T. nudiventris.
Cranial characters
The skull (Tsa2, Tsa4) is large with an average condylo-canine length of 22.6 mm (21.7-24.6 mm). It is superficially similar to that of T. nudiventris with widely flared zygomata and a well developed lambda. However, there is a clear distinction in the structure of the tympanic bullae. In T. saccolaimus , the antero-internal border of each tympanic bulla is completely ossified and in consequence the main body of the cochleae is obscured (Tsa3); in all the other local species of Taphozous the antero-internal border is incomplete and the cochleae are readily visible. The mesopterygoid space is relatively short in comparison to that of T. nudiventris and the basisphenoid pits larger.
Dentition
The dentition is robust with an average upper toothrow length of 10.3 mm (9.8-11.2 mm). It is similar in morphology to that of T. nudiventris except for the first upper premolar (PM2) which is relatively large, with a crown area of between 30-50% of the second premolar (PM4); in the other local species of Taphozous it does not exceed 15% (Fig. 54).
Karyology
2N= 44, FN= 64 based on eight male and eight female specimens from Karnataka. The karyotype is comprised of 7 pairs of metacentric, 4 pairs of submetacentric and 10 pairs of telocentric autosomes, a large X chromosome and a very small telocentric Y chromosome (Naidu and Gururaj, 1986).
Variation
Specimens from India and Sri Lanka are provisionally referred to T. s. saccolaimus . The taxon crassus was described on account of minor differences in pelage colour and in respect of having "a recurved tail and upward bending ears" (Blyth 1844). The belly in pulcher was pure white (Blyth, 1844). Neither of these latter taxa are now considered to be distinct at a specific or subspecific level.