Temminck, 1834
Trefoil Horseshoe bat
External characters (Table 38)
With an average forearm length of 51.3 mm (50.0-53.3 mm), this species is significantly smaller than R. luctus and to a lesser extent R. beddomei . Unlike R. luctus (Rlu1) and R. beddomei (Rbe2), in which the inferior surface of the sella is essentially parallel sided and broad (4.3 mm in R. luctus and 2.4 mm in the smaller R. beddomei sobrinus ), in trifoliatus , it is conspicuously narrower, especially at its apex where it measures about 1.4 mm in breadth. The pelage is long, soft and woolly in texture. It is buffy brown above and below, considerably paler than that of R. luctus and R. beddomei . The wing and interfemoral membranes are a uniform brown. The third metacarpal is short, on average about 86.6% (86.0-87.9%) of the length of the fourth metacarpal. The ears are of medium size, smaller than those of R. b. beddomei but comparable to those of R. yunanensis and R. pearsonii (Rpe1).
Cranial characters
The skull is smaller than that of R. luctus and R. beddomei (Fig. 78) with an average condylo-canine length of 20.4 mm (19.5-21.5 mm). As in R. luctus , the nasal pit is extremely well developed and is relatively deeper and narrower than that of R. pearsonii and R. yunanensis . The median nasal inflations are well developed, subequal in height to the braincase. The sagittal crest is well defined anteriorly. The mesopterygoid space is broad anteriorly; it is U-shaped but with a spicule of bone projecting posteriorly from the median part of the palate. Posteriorly the mesopterygoid space is narrow between the pterygoids. The cochleae are enlarged and with only a slight gap between them; the tympanic bullae are not greatly inflated.
Dentition
- Upper toothrow length (C-M3) averages 8.7 mm (8.4-8.9 mm). The first upper premolar (PM2) is small and situated in the toothrow.
- The second lower premolar (pm3) is extruded to varying degrees from the toothrow. The first (pm2) and third (pm4) lower premolars are sometimes in contact.
Variation
Specimens from India are referred to the nominate form R. t. trifoliatus (Sinha, 1973).
Distribution
Rhinolophus trifoliatus ranges from northern India, Myanmar and Thailand to Java and Borneo.