Cretzschmar, 1830-31
Naked-rumped Tomb bat
External characters (Table 22)
This is a medium-sized species with an average forearm length of 74.3 mm (71.0-80.0 mm). It is characterised by its naked rump (Tnu1), which may contain copious fat reserves, especially in the post-monsoon period. Males have a large gular sac which is about 10 mm in breadth (BW7); additionally there is a deep circular gland in the upper part of the chest. In females, the gular sac is less visible and the gland is absent. The chin and throat are essentially naked in both sexes. The head is flattened in appearance (Tnu2) whilst the jaws are extremely powerful (Tnu3). The ears are long and rather narrow, blackish brown in colour and semitranslucent. They are widely separated from each other and the tips bluntly rounded off. The tragus is narrowed above its base and then expanded distally to form a club-shaped extremity with a rather flat top (BW11). The pelage is short, fine and dense. It is dark brown on the dorsal surface, with pale grey hair bases; it is paler brown on the ventral aspect. The pelage does not extend on to the wing membranes on the dorsal surface and the humerus and forearm are quite naked (Tnu1). It is also absent from both aspects of the interfemoral membrane, the posterior back, lower abdomen and legs (Tnu4). The wings, which are long and narrow, are attached to the tibiae; the radio-metacarpal pouch (Fig. 52) is moderately developed. The feet have a few characteristically long, pale hairs arising from the backs of the toes. This species has a particularly strong and unpleasant odour.
Cranial characters
The skull with an average condylo-canine length of 23.4 mm (21.6-25.6 mm) is robust and strongly ridged in adult specimens; the interorbital region is broad and squared with prominent lachrymal projections. It is comparable in size to T. saccolaimus (Tsa2) and T. theobaldi but can be distinguished from T. saccolaimus by the structure of the tympanic bullae. In T. nudiventris , the antero-internal border of each bulla is incomplete, with the main body of the cochlea readily visible. In T. saccolaimus , the tympanic bullae are completely ossified internally and in consequence the main body of cochlea is obscured (Tsa3). In contrast to T. theobaldi , the zygomata are relatively broad and the lambda usually forms the most backwardly projecting part of the skull; the lambda is especially pointed in adult males and projects backwards over the occiput; the lambdoid ridges are strongly developed. The sagittal crest is absent in some specimens, usually females and well developed in others, for example older males. The basisphenoid pits of T. nudiventris are less developed than those of T. theobaldi . The mandible is robust with the horizontal rami deep. The coronoid process of each half mandible is tall with its anterior border almost vertical.
Dentition
Upper toothrow length (C-M3) averages 10.9 mm (10.3-11.8 mm). It is similar in morphology to that of T. longimanus but distinctly more robust. In contrast to T. saccolaimus , the first upper premolar (PM2) is small, scarcely exceeding the height of the cingulum of the canine and with a crown area of little more than 10-15% that of the second premolar (PM4) (Fig. 54). In T. saccolaimus , PM2 is relatively large, with a crown area of 30-50% of PM4.
Variation
Following Felten, 1962 specimens from throughout India are referred to T. nudiventris kachhensis . Brosset, 1962a noted that individuals from Ahmedabad were greyer than those from Aurangabad.
Taxonomic remarks
The taxon kachhensis was described by Dobson, 1872 on account of an alleged absence of the gular sac in both males and females. He noted that in the male the usual position of the sac is indicated by a small semicircular fold of skin; in the female the surface is smooth. In all other respects, Dobson suggested that kachhensis was closely similar to T. nudiventris . Subsequently, Felten, 1962 reviewed the nudiventris -kachhensis species group. He concluded that Dobson's character was not valid and that the two taxa were conspecific. This view has been followed by most systematists including Harrison, 1964a, Corbet and Hill, 1992, Agrawal et al. , 1992 and Koopman, 1993.