Gray, 1831
Lesser Mouse-tailed bat
External characters (Table 16)
This is a medium-sized Mouse-tailed bat with an average forearm length of 59.2 mm (52.9-64.0 mm). It is characterised by its exceptionally long tail (Rha1) which unlike that of R. microphyllum usually exceeds forearm length. The dermal ridge of the muzzle (BW6) is better developed than that of R. muscatellum (Rmu3). The pelage is similar in length and texture to that of R. microphyllum ; it is grey-brown above with paler hair roots; the belly is essentially grey. As in R. microphyllum , the interfemoral and wing membranes, posterior back and lower abdomen are naked (Rha3); the chin is nearly naked. The feet are smaller and more delicate. The baculum is very small, with a slightly bifid base and a simple narrow tip (Fig. 37b).
Cranial characters
The skull (Fig. 40) is smaller than that of R. microphyllum (Rha7) with an average condylo-canine length of 16.5 mm (15.5-17.5 mm). The rostrum is relatively larger and the nasals are more inflated. However, the inflations are not as large as those of R. muscatellum and when viewed laterally they do not project in front of the canines. The sagittal crest forms a low elevation above the frontal region; it is not usually as prominent as that of R. microphyllum . The lambdoid crests are weak. The anterior border of the mesopterygoid space is U-shaped. The tympanic bullae are less developed than those of R. muscatellum . The mandible is illustrated in (Fig. 40).
Dentition
Upper toothrow length (C-M3) averages 6.4 mm (6.0-6.8 mm). In general, the dentition (Fig. 41) is lighter than that of R. microphyllum . It is essentially similar in morphology although the first lower premolar (pm2) appears to be relatively smaller.
Variation
All specimens from the Indian subcontinent are referable to R. h. hardwickii (Van Cakenberghe and de Vree, 1994).