(Bechstein, 1800)
Lesser Horseshoe bat
External characters (Table 29)
This is a small species (Rhi1) with an average forearm length of 38.1 mm (35.9-40.0 mm). The sella is characteristically shaped (Fig. 73). In side view, its anterior margin is nearly straight; its inferior extremity projects downwards and forwards; the superior connecting process is low and broadly rounded off. The lancet is tall and narrow, its tip bluntly pointed, its sides nearly straight, not concave. Although the forearm is comparable in length to that of R. pusillus , the tibiae are significantly longer. The tail is also relatively long. The third metacarpal is considerably shorter (85.1%, 80.1-88.8%) than the combined length of its respective phalanges; in R. pusillus , R. lepidus (Rle1) and R. subbadius , the third metacarpal is about equal to or exceeds the length of the phalanges. The second phalanx of the fourth finger is noticeably long in comparison to those of R. pusillus and R. lepidus . In R. hipposideros , it is on average nearly twice the length of the first phalanx (191%, 171-203%); in R. pusillus it is only 23 percent longer (123%, 104-143%); similar values to R. pusillus are exhibited by R. lepidus and R. subbadius . In extralimital specimens, pelage colour varies considerably, ranging from pale buffy brown to a darker grey brown.
Cranial characters
The skull is delicate and small with an average condylo-canine length of 13.5 mm (13.0-14.0 mm). It is comparable in size and morphology to that of R. pusillus . The braincase is relatively narrow when compared to that of R. lepidus . The rostrum is also narrow although the median inflations are well developed. The anterior extremity of the mesopterygoid space is very broad, occupying almost the whole of the palate between the third molars (M3). The tympanic bullae are relatively smaller than those of R. pusillus although the cochleae are of comparable size.
Dentition
- Upper toothrow length (C-M3) averages 5.3 mm (4.6-5.5 mm). Both the maxillary and mandibular canines are short and delicate; the tip of the upper canine barely exceeds the anterior cusp of the second premolar (PM4) in height. The first premolar (PM2) is a well developed functional tooth which lies within the toothrow. Unlike R. pusillus and R. lepidus , the third upper molar (M3) possesses a distinct fourth commissure and a metastyle.
- The first (pm2) and third (pm4) lower premolars are usually in contact; the second (pm3) is very small, normally situated externally to the toothrow.
Variation
Following Andersen, 1918 and Topal, 1975, specimens from the Indian subcontinent are referred to R. h. midas . This subspecies is distinguished by the sella which is relatively broad across its base, when viewed from in front.