(Kuhl, 1819)
Whiskered bat
External characters (Table 64)
This is a small species of Myotis , with an average forearm length of 35.6 mm (34.5-36.8 mm). The naked parts of the face and muzzle are nearly black; the eyes are partly concealed by numerous fine hairs and the upper lip has a hairy fringe (hence the common name Whiskered bat). The ears are dark brown/ black and relatively small; the anterior border of each is evenly convex; the posterior border has a shallow concavity beneath the rounded tip. The tragus is tall and narrow, about half the height of the pinna. The feet are small, less than half the length of the tibiae. The pelage is russet brown on the dorsal surface with dark hair roots (Mmy1). The roots are also dark on the ventral surface but the tips are characteristically grey or creamy white in colour; in M. muricola , the belly is dark throughout (Mmy2). In the wing, the third metacarpal very slightly exceeds the fourth and fifth in length. The wing membranes are uniformly dark brown and are without hairs above and below; each wing is attached to the distal end of the outer metatarsal of the foot. The interfemoral membrane is also dark; there are some hairs present on the upper surface adjacent to the body and the tibiae.
Cranial characters
The skull with an average condylo-canine length of 12.1 mm (11.6-12.4 mm) is usually larger than that of M. muricola . The braincase is bulbous and elevated above the rostrum, but not as abruptly as in M. siligorensis . The rostrum is narrow, shallow and has a very slight depression in the mid-line extending from the nasal orifice to the frontals. The sagittal crest is scarcely evident. The supraoccipital is convex and forms the most posterior part of the skull. In turn, the lambda just forms the most elevated part of the skull. Zygomatic breadth exceeds that of the braincase but each zygoma is short and fragile. The anterior emargination of the palate extends backwards to a level equal to the mid-line of the canines. Each half mandible has a relatively shallow horizontal ramus; its depth is about equal to the height of the protoconid of m1; the height of the coronoid process greatly exceeds that of the canine.
Dentition
- Upper toothrow length (C-M3) averages 5.0 mm (4.7-5.3 mm) and is distinctly more robust than that of M. siligorensis . The first upper incisor (I2) is bicuspidate, with its posterior cusp about half or less the height of the principal cusp. The second incisor (I3) has a large outer cusp and a small accessory cusp on its inner surface. There is a short gap to the canine which exceeds the third premolar (PM4) in height; the canine is without accessory cusps but has a well defined cingulum. The anterior upper premolars are small, with the second (PM3) usually about two-thirds the crown area of the first (PM2); both lie within the toothrow. M1 and M2 are about equal in crown area and both have a well developed protocone; the paracone and metacone are about equal in height. M3 is about two-thirds the crown area of M2; it includes a metacone and a very short fourth commissure; the metastyle is absent.
- The first lower incisor (i1) has three cusps; the second (i2) also has three cusps but with an additional very small accessory cusp postero-medially. The third incisor (I3) is considerably broader and has four distinct cusps. The first lower premolar (pm2) is half the crown area of the third (pm4) and twice the crown area of the second (pm3). The talonid of m1 and m2 slightly exceeds the trigonid in crown area. In m3, the talonid is subequal to the trigonid in size.
Variation
Specimens from the region are provisionally referred to M. m. nipalensis ; the status of meinertzhageni is unclear, the holotype is considerably paler dorsally than typical nipalensis (Hill, 1983), possibly it may represent a distinct race of M. mystacinus .
Taxonomic remarks
Although Ellerman and Morrison-Scott, 1951 included muricola as a subspecies of M. mystacinus , the view was subsequently challenged by Corbet, 1978. Hill, 1983 discussed the status of mystacinus , muricola and siligorensis in detail and subsequently treated them as three distinct species (Corbet and Hill, 1992).