Murina pluvialis, Ruedi & Biswas & Csorba & Mr, 2012

Ruedi, Manuel, Biswas, Jayant & Csorba, Gábor, 2012, Bats from the wet: two new species of Tube-nosed bats (Chiroptera: Vespertilionidae) from Meghalaya, India, Revue suisse de Zoologie 119 (1), pp. 111-135 : 116-120

Murina pluvialis sp. nov.

HOLOTYPE: MHNG 1976 .071 (field number M1646), adult female, in spirit, skull removed, collected by MR and JB on 21 February 2011.

TYPE LOCALITY: India, Meghalaya, Khasi Hills, village of Laitkynsew , 780 ma.s.l. (metres above sea level); geographic coordinates: N 25°13’, E 91°40’ .

ETYMOLOGY: The name pluvialis (“related to rain” in Latin) refers to the habitat of the new species, which reportedly receives the highest annual rainfall in the world. The proposed English name is Rainforest tube-nosed bat.

DIAGNOSIS: The plagiopatagium is attached to the base of the claw of the outer toe. Dorsal hairs dark brown basally, the distal part reddish, the fur without shiny individual hairs; ventrally the hairs black at their basal half and light grey on the upper half. Basal area of C 1 equals that of P 4, mesostyles of M 1 and M 2 reduced but possessing distinct cusps. Forearm 36.6 mm, maxillary toothrow length 5.49 mm.

DESCRIPTION: A medium-sized species of Murina (Table 2). External measurements of the holotype female are: head and body 44 mm, tail 34 mm, ear 16 mm, tragus 7.5 mm, hindfoot 6.5 mm, tibia 17.6 mm and forearm 36.6 mm. On the dorsal surface the hairs show a clear banding pattern: the basal third is very dark brown, almost black, the middle part yellowish-reddish, and the tip bright red; fur without shiny guard hairs. The upper surface of uropatagium near the body is densely covered in long reddish hairs. Ventrally, hairs are dark grey for the proximal half, while the upper portion is silvery grey (Figs 1-2). The ventral side of uropatagium has sparse whitish hairs. The ear is evenly rounded and without an emargination. The plagiopatagium is attached to the very base of the claw on the outer toe (Fig. 3).

The skull is medium sized (Table 2). The braincase is domed, with rostrum not inflated. A sagittal crest is evident and runs continuously from the frontal part of the skull posteriorly to the lambda. The lambdoid crests are also well pronounced. The narial emargination is as wide as long and the zygoma are strong but lack any dorsal prominences (Figs 4-5).

The maxillary toothrows are convergent anteriorly (C 1 C 1 W/M 3 M 3 W = 0.76). I2 is largely obscured in the lateral view, exceeds in height I 3 and comprises less than one half of the latter’s basal area. The basal area of C 1 equals that of P 4 and clearly exceeds P 4 in height. P 2 basal area and height are approximately two-thirds that of P 4. The mesostyles of M 1 and M 2 are reduced but retain distinct cusps and equal their respective paracones in height.

The lower canine (C 1) exceeds P 4 in height and is greater in basal area; P 2 is compressed antero-posteriorly, while its basal area is less than that of P 4 and nearly attains its height. The crown area of the M 1 talonid equals its trigonid while the M 2 talonid is clearly smaller than its corresponding trigonid and the entoconids of these teeth exceed their hypoconids in height. The postcristid possess a deep indentation and end posterior to the tip of the entoconid.

COMPARISONS WITH OTHER TAXA: On the basis of its dentition (I 2 obscured by I 3 in lateral view, C 1 basal area not less than that of P 4, P 2 basal area more than half that of P 4) M. pluvialis belongs to the “ cyclotis -group” and is therefore readily distinguished from all members of the “ suilla -group” currently described. Within the “ cyclotis -group” M. aenea and M. cyclotis are characterised by the reduced cusp-pattern of molars with missing mesostyles on M 1 and M 2 and by M 1 and M 2 with a talonid much smaller in area than their respective trigonids. Among these species, only M. cyclotis is known to occur in continental South Asia ( Srinivasulu et al., 2010); this species has dorsal and ventral pelage, ear shape and craniodental measurements similar to those of TABLE 2. Selected external and craniodental measurements (in mm) of some Murina species. Values are given as min–max, (n). Acronyms and definitions for measurements are given in the text.

Character M. pluvialis M. sp. A M. cyclotis M. rozendaali sp. nov.

FA 36.6 30.0-31.7 (3) 29.4-34.5 (18) 31.2-33.2 (5) STOTL 16.4 15.63-16.09 (3) 15.66-17.62 (20) 14.81-16.05 (4)) CCL 14.5 13.75-14.21 (3) 13.56-15.41 (21) 13.09-13.97 (4) C 1 C 1 W 4.21 3.86-3.91 (3) 3.73-4.68 (21) 3.78-4.31 (5) M 3 M 3 W 5.52 5.24-5.30 (3) 5.08-5.89 (21) 5.25-5.50 (5) ZYW 9.26 8.63-8.96 (3) 8.76-10.17 (21) 8.85-9.41 (5) MAW 7.78 7.59-7.69 (3) 7.54-8.31 (21) 7.35-7.74 (5) IOW 4.32 4.04-4.21 (3) 3.89-4.50 (22) 3.95-4.31 (5) BCH 6.43 6.01-6.26 (3) 5.98-6.81 (21) 5.86-6.23 (5) CM 3 L 5.49 5.23-5.29 (3) 5.12-5.86 (21) 5.16-5.53 (5) ML 11.18 10.43-10.62 (3) 10.41-12.10 (22) 10.30-10.89 (5) CM 3 L 5.93 5.7-5.84 (3) 5.56-6.26 (21) 5.76-6.14 (5) CPH 4.02 3.64-3.73 (3) 3.77-4.78 (21) 3.33-4.03 (5)

M. pluvialis , but is readily distinguishable from the latter by its smaller forearm and especially by the above mentioned cusp arrangement on the upper molars (Fig. 6). In relation to other members of the ‘ cyclotis -group’ in the Indomalayan Region, M. harrisoni , M. huttoni , M. puta and M. tiensa are all much larger craniodentally with no overlap in CCL, MAW, CM 3 L and CM 3 L measurements ( Csorba et al., 2007) and none of them possess predominantly dark belly fur. The only species with similar craniodental dimensions and with distinct mesostyles on upper molars and developed talonids on lower molars in the “ cyclotis -group” are M. sp. A (a currently unnamed taxon from Indochina) and M. rozendaali (Fig. 5).

The pelage of M. sp. A is basically the same being predominantly reddish brown dorsally without shiny guard hairs and dark-based ventrally but is distinguished externally by its much shorter forearm. Cranially M. sp. A is characterised by the lack of sagittal crest (developed in M. pluvialis ) and dentally by the following features: CM 3 L 5.30 mm or less; P 2 approximately the same height as P 4, mesostyles of M 1 and M 3 are higher than corresponding paracones; and M 2 talonid equals its trigonid (whereas M. pluvialis has a longer upper toothrow; P 2 reaches only two-third of P 4 in height; mesostyles and corresponding parastyles of M 1 and M 2 are subequal; and M 2 talonid decidedly smaller than the trigonid).

The pelage of M. rozendaali completely differs from that of M. pluvialis being dorsally dark brown with shining yellow or golden tips and uniformly white on the belly. In the dentition of M. rozendaali mesostyles are well developed and entoconids are of equal height as hypoconids, whereas in M. pluvialis the mesostyles of M 1 and M 2 are poorly developed and entoconids of M 1 and M 2 exceed their hypoconids in height.

DISTRIBUTION AND ECOLOGY: The holotype and currently only known specimen of M. pluvialis was an adult female with no external sign of reproduction, caught in the secondary, dense evergreen forest located close to the village of Laitkynsew. This forest lies on the steep slopes of the southern ridge of the Shillong plateau and receives very high orographic rains brought by the seasonal monsoons ( Thabah & Bates, 2002).

FIG. 1

Living specimens of (a) M. pluvialis (holotype, MHNG 1976.071) and (b) M. jaintiana (holotype, MHNG 1976.072).

FIG. 2

Detailed view of (a) dorsal and (b) ventral pelage of M. pluvialis (holotype, MHNG 1976.071) and (c) dorsal and (d) ventral pelage of M. jaintiana (holotype, MHNG 1976.072).

The harp-trap that caught M. pluvialis was set up across a small path leading through a small bamboo grove intermixed with other native flora. Other bat species caught in the same harp-trap included Rhinolophus pearsoni, R. macrotis, Hipposideros fulvus and Kerivoula kachinensis . No other information is currently available on the ecology of M. pluvialis , but Bates & Harrison (1997) mention that M. “ cyclotis ” (i.e. the taxon with which pluvialis was most likely confounded) appears to have been a relatively common species in the Khasi Hills of Meghalaya, with some 30 specimens collected for the Field Museum of Natural History, Chicago (FMNH) ( Bates & Harrison, 1997: p. 207).