Blyth, 1844
Blyth's Horseshoe bat
External characters (Table 32)
Although this is a small Rhinolophid with an average forearm length of 39.8 mm (37.0-41.8 mm), it usually exceeds R. pusillus in size. The general morphology of the noseleaf (BW16, BW17) is comparable to that of R. pusillus . However, when viewed laterally, the tip of the triangular shaped connecting process is generally more broadly rounded off. The anterior surface of the sella is also less conspicuously emarginated and significantly longer (although this is less evident in the Himalayan form R. l. monticola ). The lancet is well developed; the tip is variable in shape, in some specimens it is broadly rounded off and in others more pointed; some individuals have deeply concave sides adjacent to apex and in others, the sides of the lancet are almost straight. It is usually distinguished from R. pusillus by its average longer forearm and tibia measurements. However there is some overlap in all the external and cranial measurements between the two taxa and a minority of specimens from Himalayan region are difficult to assign with confidence to one or other species (including the holotype of monticola , see Variation below). The pelage colour is typically grey-brown dorsally and slightly paler ventrally (Rle1); a minority of individuals are considerably darker.
Cranial characters
The skull, although small, usually exceeds that of R. pusillus in size, especially the condylo-canine length which averages 14.6 mm (13.8-15.5 mm). The rostral inflations are well developed in specimens of R. l. lepidus from peninsular India and the palatal width (M3-M3= 6.1 mm; 5.8-6.3 mm) exceeds that of R. pusillus (5.6 mm; 5.4-5.8 mm). However, the rostral inflations are less well developed in specimens of R. l. monticola and the palate is relatively narrower (5.9 mm; 5.7-6.0 mm).
Dentition
- The upper dentition (C-M3) usually exceeds 6.0 mm in length (6.3 mm; 6.0-6.8 mm) in R. l. lepidus ; in R. pusillus it is normally less than 6.0 mm (5.8 mm; 5.4-6.0 mm). However specimens of R. l. monticola are intermediate in size, 5.9 mm; 5.6-6.3 mm. The upper canine is well developed. It is almost twice the height of the second upper premolar (PM4). The first premolar (PM2) is a functional tooth that lies within toothrow.
- The second lower premolar (pm3) is small; it is usually, but not always situated externally to the toothrow: occasionally it is absent. The first (pm2) and third (pm4) lower premolars are sometimes in contact.
Variation
Following Hill and Yoshiyuki, 1980, specimens from the Himalayan region of northern India, Pakistan and Nepal are provisionally referred to R. l. monticola (N5). In general, these northern montane individuals are characterised by their smaller size, especially the cranial and dental measurements. However, the holotype (BM.79.11.21.151) of monticola is an unusually small individual; externally (forearm = 37.0 mm) it is within the range of R. pusillus although its cranial measurements (condylo-canine length= 14.1 mm) are consistent with those of R. lepidus . The possibility of a mis-matched skull has to be considered. A juvenile topotype of monticola (BM.79.11.21.152) is typical of R. lepidus in all respects (forearm = 39.6 mm).