Temminck, 1835
Rufous Horseshoe bat
External characters (Table 28a, Table 28b, Table 28c)
This species is very variable in size throughout the subcontinent. In general, the forearm length (44.4-52.3 mm) averages smaller than R. affinis . The ears are slightly larger than those of R. affinis (Raf1) but smaller than those of R. ferrumequinum (Rfe1). The noseleaf (Rro5) is broader but otherwise similar to that of R. ferrumequinum (Rfe3). The lancet is of variable height, sometimes triangular in shape with straight sides, sometimes with a well developed tip and concave margins below. In the wing, the third metacarpal is not conspicuously shortened, as in R. ferrumequinum . The first phalanx of the third metacarpal is less than half the length of the metacarpal. The second phalanx of third metacarpal is usually less than 66% of the length of the metacarpal (except in specimens of R. r. sinicus from the Himalayas); in R. affinis it is usually about 73%. The pelage is soft and silky, not woolly as in the larger R. beddomei (Rbe1). There is considerable variation in pelage colour ranging from orange (Rro2), to russet brown (Rro4) to buffy brown to grey (Rro3); empirical evidence suggests a seasonal bias in colour such that the orange and rufous tints predominate from October to April and the paler phases are more common in specimens collected from May to September; there is no sexual bias. The baculum has a long, parallel-sided shaft and the base is expanded (Fig. 65). The mean length is 2.3 mm and the greatest width 0.7 mm (Thomas, in prep).
Cranial characters
Skull size (Fig. 66) varies considerably with the condylo-canine length ranging from 17.4 to 21.0 mm. The zygomata are less flared posteriorly than those of R. ferrumequinum but the anterior border of the mesopterygoid space is significantly broader. In comparison to R. affinis , palatal length tends to be longer, on average up to one third the length of the upper toothrow in specimens from peninsular India and Sri Lanka (shorter in specimens from the Himalayas), in R. affinis it is usually about one quarter or less.
Dentition
- The dentition, with an upper toothrow length of 7.6-9.2 mm is less robust than that of R. ferrumequinum (Fig. 61b). The upper canine is not in contact with second upper premolar (PM4) and the first upper premolar (PM2) is usually situated in the toothrow (Fig. 68).
- The second lower premolar (pm3) is also usually situated in the toothrow, although it may be displaced externally, particularly in specimens from the Himalayas and Sri Lanka; the first (pm2) and third (pm4) premolars are sometimes in contact.
Karyology
2N= 58, FN= 62 based on specimens from Poona; there is one pair of metacentric, one pair of submetacentric, one pair of subtelocentric and 25 pairs of acrocentric chromosomes; the X chromosome is a larger subtelocentric and the Y chromosome a small acrocentric (Dulic, 1980).
Variation
Specimens from the Himalayas are referred to R. r. sinicus (Rfe5). They are characterised by their small cranial measurements but relatively large wings; the second phalanx of the third metacarpal is very long, averaging 69.9% (65.0-75.3%) of its respective metacarpal length, this is subequal to that of the larger R. affinis . Specimens from peninsular India are the largest from the region and are referred to R. r. rouxii ; the second phalanx of the third metacarpal averages 62.0% (55.6-67.5%) of the metacarpal length. Those from Sri Lanka have smaller wings but larger skulls than the Himalayan specimens and are here referred to R. r. rubidus ; the second phalanx of the third metacarpal is relatively very short averaging only 58.1% (52.8-63.5%) of the metacarpal length.