Murina balaensis Soisook, Karapan, Satasook & Bates, 2013, sp. nov.
Creators: name: Soisook, Pipat
name: Karapan, Sunate
name: Satasook, Chutamas
name: Bates, Paul J. J.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Chiroptera
Vespertilionidae
Murina
Murina balaensis

description: Murina balaensis sp. nov.
(Fig. 1–5)
Type materials. Holotype. PSUZC-MM2012.214, field number PS121013.1, adult male, dry skin with skull and baculum extracted, collected by Abdullah Samoh, Saowaluk Binlasoi and Jirapan Yimkaew on 13 October 2012, during a faunal diversity survey of Halabala Wildlife Research Station.
Type locality. Thailand, Narathiwat Province, Wang, Halabala WS, Bala Forest, Second bridge trail, 5 ° 48.9’N, 101 ° 48.1’E, 370 m a.s.l.
Paratype. PSUZC-MM2012.215, field number PS120928.1, adult female, dry skin with skull extracted, collected from the same general area as the holotype, but at approx. 5 ° 48.5’N, 101 ° 48.4’E, 340 m a.s.l., collected by Abdullah Samoh, Saowaluk Binlasoi, Jirapan Yimkaew and Pipat Soisook on 28 September 2012.
Etymology. The name balaensis refers to the type locality, Bala Forest, from where the type specimen was collected. The proposed English name is Bala Tube-nosed bat.
Measurements of the holotype: MASS: 3.5 g, FA: 28.0, HB: 34.5, TL: 30.7, HF: 7.0, TIB: 14.5, 3MET: 26.8, 4MET: 26.5, 5MET: 26.6, 3D1P: 11.3, 3D2P: 10.4, E: 12.8, Tragus: 7.4, GTL: 14.42, STOTL: 14.03, CBL: 13.10, CCL: 12.31, ZB: 8.21, BB: 6.86, MW: 7.11, PC: 4.12, BCH: 5.33, C–M3: 4.66, C–P4: 1.99, C1–C1: 3.44, M3–M3: 4.90, C–M3: 5.04, C–P4: 1.83, M: 9.63, CPH: 3.13, TRM1: 0.68;TAM1: 0.56; BL: 1.0.
Diagnosis. This is a small bat, with a FA of 28.0, 30.4 mm, STOTL 14.03, 14.81 mm and CCL of 12.31, 12.98 mm (Table 1). The dorsal pelage is dark-grey at the base and orange-reddish brown distally; some hairs are charcoal black at the tip; longer shiny golden hairs are scattered over the dorsal side (Fig. 1). The ventral pelage is dark-grey basally and whitish grey at the hair tips. The wing membrane is attached to the distal phalanx of the outer toe, 2 mm below the base of the claw. The absolute height of the upper canine (C1) slightly exceeds that of the second upper premolar (P4) (Fig. 2). However when viewed in lateral profile, the tip of the crown of the canine (C1) appears in line or slightly above that of P4. The cingular cusp on the lingual surface of the upper canine (C1) is very well developed. The outer upper incisor (I3) is large, with a crown area about twice that of the inner incisor (I2). The first upper premolar (P2) is elliptical. The second upper premolar (P4) is rounded. The lower canine (C1) exceeds in height the second lower premolar (P4). The talonid in both the first and second lower molars (M1 and M2) is slightly less in crown area than that of the respective trigonid and the entoconid is lower than the hypoconid.
Characters M. balaensis sp. nov M. eleryi
♂PSUZC-MM2012.214 ♀PSUZC-MM2012.215 ♂♂ (n=2) ♀♀ (n=2)
(holotype) (paratype)
Description. This is a small Murina with a FA of 28.0, 30.4 mm, HB 34.5, 42.5 mm and the body mass of 3.5, 4.0 g (Table 1). The ear, which is 12.3, 12.8 mm in height, is rounded with no distinct emargination on the posterior border of the pinna. The pinna is almost naked and brown in colour, except at the anterior base, which is paler. The tragus is white throughout and short, 7.4, 7.6 mm; it is less than half the height of the ear (Fig.1 a). The dorsal pelage is ashy–grey basally for about 40% of hair length; most of the hair tips are orange-reddish brown but some have a charcoal black tip. Bright shiny silver–golden guard hairs are present on the head, the back, the base of the uropatagium and on the dorsal side of the foot (Fig.1 b–c). The ventral pelage is dark grey basally and whitish grey on the hair tips (Fig.1 d).
In the wings, the thumb is relatively long, 8.2, 8.8 mm. The 3rd metacarpal (3MET), 26.8, 28.0 mm, is slightly longer than that of the 4th and 5th metacarpals (4MET and 5MET), which are about subequal in length, 26.5, 27.7 mm and 26.6, 27.7 mm, respectively. The first (3D1P) and second phalanges (3D2P) of the third digit are 11.3, 13.1 mm and 10.4, 11.9 mm, respectively. Each plagiopatagium is naked and dark brown in colour on both the dorsal and ventral surfaces; it is attached to the distal phalanx of the outer toe, 2 mm below the base of the claw (Fig.1 b). The feet are hairy dorsally, relatively small, 6.6, 7.0 mm, and less than half of the tibia length, which is 14.3, 14.5 mm. Tail length is 30.6, 30.7 mm. Each calcar is well developed and without a keel, its length is 47.0–53.0% of the trailing edge of the uropatagium.
FIGURE 2. Skull (a-d) of the holotype of M. balaensis sp. nov., male PSUZC-MM2012.214 from Thailand; (e) lingual view of upper left I2 – P4 of the holotype. Scale bars = 5 mm and 3 mm, as indicated. The lower toothrow is shown in the Fig. 3.
In the skull, the greatest length (GTL) is 14.42, 14.95 mm, STOTL 14.03, 14.81 mm, CBL 13.10, 13.68 mm, and CCL 12.31, 12.98 mm (Table 1). Each zygoma is very thin and without a dorsal protuberance; the breadth (ZB) is 8.21 mm. The breadth of braincase (BB) and mastoid (MW) are 6.86, 6.90 mm and 7.11, 7.52 mm, respectively. In lateral view, the profile from the posterior part of the rostrum to the anterior part of the braincase exhibits only a slight concavity (Fig. 2). The braincase and lambdoid are without a sagittal crest and are relatively low (Fig. 2a), with a BCH of 5.33, 5.52 mm. The basioccipital pit and the palatal depression are very shallow (Fig. 2d). The upper toothrows converge anteriorly; the width at C1–C1 is 70.20% and 71.26% of that at M3–M3. The maxillary toothrow length (C–M3) is 4.66, 4.88 mm. The upper canine–second upper premolar length (C–P4) is 1.99, 2.03 mm, which is 41.60% and 42.70% of the maxillary toothrow length. The inner upper incisor (I2) is placed forward of the outer upper incisor (I3). In lateral view, they are both clearly visible and are about equal in height. The upper canine (C1) is relatively small in comparison to the second upper premolar (P4); its crown area is about two-thirds or slightly less than that of P4; its absolute height slightly exceeds that of P4. However when viewed in lateral profile, the tip of the crown of C1 appears in line or slightly above that of P4 (Figs. 2 and 3). The cingular cusp on the lingual surface of both C1 and P4 is very well developed (Fig. 2e). The first upper premolar (P2) is somewhat elliptical, its crown area is about half that of the P4, and its height is about half that of C1 and P4 (Fig. 3). P4 is relatively large, rounded in shape (Fig. 3). The mesostyle of the first (M1) and second molars (M2) are well developed and the shape of the labial surface of both teeth is convex.
The length of the mandible (M) is 9.63, 10.44 mm. The mandibular toothrow length (C–M3) is 5.04, 5.38 mm. The C–P4 is short, 1.83, 1.93 mm, which is 35.87%, 36.31% of mandibular toothrow length. The lower incisors (I1 to I3) are all tricuspidate. The lower canine (C1) exceeds the first (P2) and second lower premolars (P4) in height; its crown area exceeds that of P2 and is about equal or slightly more than that of P4 (Fig. 3 a–b). P2 is about two-thirds that of the P 4 in crown area and about equal in height. The anterior and posterior basal cusps of the P2 are well developed and are partially situated above the posterior border of C1 and the anterior border of P4 (Fig. 3 a–b). The second lower premolar (P4) is relatively large, with a crown area about equal or slightly less than that of lower canine. The talonid of the first (M1) and second lower molars (M2) is slightly smaller than that of its respective trigonid in crown area. The height of the entoconid is two-thirds that of its hypoconid on M1; it is subequal in M2. The coronoid process is well developed, 3.13, 3.48 mm in height.
The baculum (Fig. 4 a) is almost rectangular in shape, but has rounded corners and a slight concavity on the anterior and posterior margins; it is very small, with a greatest length (BL) of 1.0 mm and a width of 0.6 mm. The dorsal surface is arched upwards and the ventral surface is deeply concave throughout its length.
Echolocation. Free flying individuals emitted a typical broadband frequency-modulated signal. There was a slight difference between male and female specimens in call parameters, which were as follows; [fmaxe]: male = 90.7–107.3 kHz, female = 84.6–95.3 kHz; [sf]: male = 145.9–159.7 kHz, female = 159.0–164.0 kHz; [tf]: male = 65.5–67.0 kHz, female = 62.0–66.9 kHz; [d]: male = 1.7–2.6 ms, female = 1.9–3.0 ms.
Comparison with similar species. According to the dental characters, M. balaensis belongs to the ‘suillagroup’ (sensu Corbet and Hill, 1992). It can be separated from all other Murina species in the ‘ cyclotis -group’ in having a relatively small P2 and C1; the crown area of P2 is about half that of the P4; the crown area of the upper canine (C1) is about two-thirds or slightly less that of the P4. In the ‘ suilla -group’, it can be distinguished from other species by its distinct pelage colour and a very well developed cingular cusp on the upper canine. The only two species that share a similar pelage colour and have a well developed cingular cusp on the upper canine are M. eleryi which is known from northern Vietnam and Lao PDR (Furey et al., 2009; Francis and Eger, 2012) and M. aurata which is thought to be restricted to mountains in and around Moupin, Tibet (Eger and Lim, 2011).
M. balaensis is most similar to M. eleryi. However, it differs significantly in having a very well-developed cingular cusp on the upper canine (Fig. 2e) whereas it is much less developed in M. eleryi. When the skull is held in the horizontal plane and viewed laterally, the C1 of M. eleryi exceeds P 4 in length, but it is only about equal or less than that of P 4 in M. balaensis (Fig. 3). The tragus of M. balaensis is white but in M. eleryi, it appears to have a dark tip (although this may not be a constant character in every individual; Furey et al., 2009; Fig. 1 A). The dorsal hair colour of both species is very similar. However, the ventral pelage of M. balaensis is somewhat duller, light grey rather than the creamy white of M. eleryi. In the skull, M. balaensis has a more elongate rostral–interorbital region and lambdoid (Fig. 3), with a relatively lower braincase height (BCH) 5.33–5.52 mm versus 5.44–5.78 mm in Furey et al. (2009). The lateral profile from the interorbital region to the anterior part of the braincase of M. balaensis rises gradually but it is more markedly concave in M. eleryi (Fig. 3). The basioccipital pit and palatal depressions of M. balaensis are very shallow whereas in M. eleryi these depressions are distinctly deeper. In M. balaensis, the P4 is somewhat rounded, being wider than long but M. eleryi, the P4 is more rounded (Fig. 3). In the mandible, in M. balaensis, the crown area of the talonid of M1 and M2 is less or only about equal to its respective trigonid, in M. eleryi, the talonid exceeds the trigonid in crown area (Fig. 3; see also Furey et al., 2009). The specimens of M. eleryi examined have a proportion of the talonid to the trigonid of the M1 of 85.7–90.6% (n=3) in length, versus 80.6% and 82.4% in M. balaensis. Moreover, the height of the entoconid is less than that of its respective hypoconids in M. balaensis, but in M. eleryi the entoconid exceeds that of the hypoconid in both M1 and M2. The baculum of M. balaensis is shorter than that of M. eleryi (1.0 versus 1.4 mm, respectively); there is only a very slight concavity on the anterior and posterior margins whereas in M. eleryi the anterior border is very strongly concave and the posterior margin is slightly concave (Fig. 4).
Although the general appearance of the pelage and the length of the upper canine of M. balaensis are similar to the Tibetan species M. aurata and another Vietnamese species M. harpioloides Kruskop and Eger, M. balaensis can be differentiated from these two species on the basis of dental morphometrics. The crown area of the C1 of M. balaensis is about two-thirds or subequal to that of P4 whereas the C1 is only slightly more than half that of the P 4 in M. aurata (Kruskop and Eger, 2008; Furey et al., 2009). Furthermore, the lower canine (C1) of M. aurata is very small and does not exceed that of P 4 in height, which is in contrast to a high and well developed C 1 in M. balaensis (Fig. 2a; see also Maeda, 1980; Kruskop and Eger, 2008; Furey et al., 2009). In M. harpioloides, the C1 is without a cingular cusp, and much smaller in size, and the P4 is more rounded than in M. balaensis. Furthermore, the talonid of the M2 of M. harpioloides exceeds that of the trigonid in size but in M. balaensis, the talonid is slightly less or only about equal to that of the trigonid (Fig. 3; see also Kruskop and Eger, 2008).
Ecology and distribution. The male specimen (holotype) was collected in a harp trap set across a forest trail leading uphill in cluttered, moist, evergreen forest at an elevation of 370 m. It was caught at 19.45 hrs just before it started to rain. The female specimen (paratype) was collected in a harp trap set in the very dense understorey of a plain–lowland moist evergreen forest at an elevation of 340 m and approximately 800 m away from the site of the holotype. M. balaensis was captured together with Hipposideros atrox Andersen, Kerivoula hardwickii Thomas, K. minuta Miller, K. pellucida Waterhouse and Murina suilla (Temminck). The general habitat of M. balaensis at HBWRS is lowland Malaysian-type evergreen rain forest. M. eleryi, however, has been found in a more heavily degraded habitat in limestone forests at an elevation over 500 m asl. (Furey et al., 2009).
So far, M. balaensis is known only from two specimens collected from the type locality. However, further field surveys using harp trap may extend its range, particularly in the lowland evergreen forest habitats of peninsular Malaysia.
Genetic analysis. The genetic analysis suggested that M. balaensis sp. nov. is most closely related to M. eleryi from China and Vietnam (Fig. 5) but differs from it by about 8% in genetic distance. This genetic distance is relatively low but exceeds differences of approximately 5% observed for intraspecific variation in Murina species, as suggested by Francis et al. (2010) and Francis and Eger (2012). Moreover, the disjunct distribution as well as the habitat and morphological differences as described above, support the distinction between M. balaensis and M. eleryi. Further genetic study, particularly concerning the relationship with other species using additional genetic markers, is recommended.
description: Published as part of Soisook, Pipat, Karapan, Sunate, Satasook, Chutamas & Bates, Paul J. J., 2013, A new species of Murina (Mammalia: Chiroptera: Vespertilionidae) from peninsular Thailand, pp. 567-579 in Zootaxa 3746 (4) on pages 569-576, DOI: 10.11646/zootaxa.3746.4.4, http://zenodo.org/record/218648