Blyth, 1848
Tail-less Leaf-nosed bat
External characters (Table 56)
This is a small Hipposiderid bat with an average forearm of 40.3 mm (37.8-42.0 mm). The tail is rudimentary, less than 2 mm in length, this distinguishes it from all other local species of Hipposideridae; in consequence the interfemoral membrane is poorly developed (Cfr1). The noseleaf is diagnostic (Fig. 113, Cfr4). The anterior leaf, which is divided into two parts by a median emargination, extends beyond the muzzle; this extension is further emphasised by the presence of two elongated, narrow, forwardly projecting supplementary lappets. The intermediate leaf has a moderately developed median process. The posterior leaf is not subdivided by vertical septa; it has a single well defined cell and a median process on its upper edge. The sides of the noseleaf are covered with long hairs, as is the face generally (Cfr2). The pelage (based on specimens from Taiwan) is soft and very long, about 9 mm mid-dorsally; it is a dull chestnut brown in some individuals, darker in others. The ears are broad, with rounded tips and convex sides (Cfr3); each has a large antitragal lobe which is not separated by a notch from the rest of the ear conch. In the wing the first metacarpal (thumb) is comparatively long (6.5 mm); it is about 3.5-4.5 mm in Hipposideros ater which has a forearm of similar length; in contrast the first phalanx is very short. The third metacarpal is significantly shorter than the fourth and fifth. The baculum is minute; it has a slender shaft with the tip slightly expanded and the base feebly bilobate.
Cranial characters
The skull (Fig. 114) is small with an average condylo-canine length of 14.5 mm (14.3-14.8 mm). The braincase is characteristically bulbous, greatly exceeding in height and breadth the small, flattened rostrum. The nasals are little inflated and the dorsal profile is straight from the upper surface of the nasal orifice to the highest point of the braincase. Sagittal and lambdoid crests are virtually absent. The zygomata are subequal in width to the braincase and are without dorsal processes. The palate is short. The cochleae and tympanic bullae are little inflated. The coronoid process of each half mandible is less developed than that of Asellia (Fig. 110).
Dentition
- Upper toothrow length (C-M3) averages 5.9 mm (5.8-6.0 mm). The upper incisor (I2) is small and bicuspid, the inner cusp larger than the outer. The upper canine has a broad shaft; there is a well developed secondary cusp that attains half the height of the shaft (Fig. 114); the anterior cusp is less distinct but of equal height. The first premolar (PM2) lies within the toothrow (Fig. 115). The second premolar (PM4) is slightly rotated within the toothrow so that the parastyle is in line with the inner margin of the canine. M3, like that of Triaenops , is not reduced; it has three distinct commissures.
- The lower incisors are both trilobate. The lower canine is short and slender. It scarcely exceeds the second lower premolar (pm4) in height which in turn is about twice the height of the first premolar (pm2). Both the premolars and molars are narrow. Unlike A. tridens , m3 is not reduced; it exceeds m1 in crown area. Harrison, 1964b noted the presence of a distinct gingival crest, situated adjacent to the second lower premolar (pm4) and m1. He suggests this may act as a "kind of natural toothbrush".