Leptobrachium mouhoti, Stuart Ko Sok Thy Neang, 2006

Stuart Ko Sok Thy Neang, Bryan L., 2006, A Collection Of Amphibians And Reptiles From Hilly Eastern Cambodia, Raffles Bulletin of Zoology 54 (1), pp. 129-155 : 131-135

Leptobrachium mouhoti , new species

( Figs. 2-4 )

Material examined. – Holotype: FMNH 262756 , adult male, in shallow water among tree roots at bank of O Doeung Por Stream in hilly evergreen forest, near 12°18'08.4"N 107°03'08.1"E, 500 m elev., Seima Biodiversity Conservation Area , O’Rang District, Mondolkiri Province, Cambodia; coll. B. L. Stuart, K. Sok, and T. Neang, 2 Nov.2003.

Paratypes: FMNH 261757-60, 261762-63 (six adult males), FMNH 261761 (one adult female), evergreen mixed with deciduous and bamboo forest, near 12°18'06.4"N 107°03'06.1"E, 600-700 m elev., Phnom Nam Lyr Mountain, Phnom Nam Lyr Wildlife Sanctuary, O’Rang District, Mondolkiri Province, Cambodia, coll. B. L. Stuart, D. An, and P. Suon, 16-17 Jun.2000. FMNH 261764 (one adult male), gallery evergreen forest along stream, near 12°29'49"N 107°29'33"E, 700 m elev., Phnom Nam Lyr Mountain, Phnom Nam Lyr Wildlife Sanctuary, O’Rang District, Mondolkiri Province, Only species with preserved voucher specimens are reported here. Specimens with affinities to Limnonectes hascheanus , Philautus banaensis and Cyrtodactylus irregularis were collected during this fieldwork, but will be treated elsewhere.

For the sake of brevity, localities are given with district name as the largest political unit (Table 1).

Cambodia, coll. B. L. Stuart, D. An, and P. Suon, 22 Jun.2000. FMNH 261765 (one adult male), gallery evergreen forest along stream, near 12°29'41"N 107°31'09"E, 700 m elev., Phnom Nam Lyr Mountain, Phnom Nam Lyr Wildlife Sanctuary, O’Rang District , Mondolkiri Province , Cambodia, coll. B. L. Stuart, D. An, and P. Suon, 23 Jun.2000. FMNH 262753-55 (three adult males), hilly evergreen forest, waterfall on O Ngeugn Stream, 12°18'50.5"N 107°06'03.4"E, 500 m elev., Seima Biodiversity Conservation Area, O’Rang District , Mondolkiri Province , Cambodia, coll. B. L. Stuart, K. Sok, and T. Neang, 11 Dec.2003; FMNH 262757 (one adult male), same data as holotype except date of collection on 6 Nov.2003 .

Comparative material examined: Leptobrachium banae FMNH 258079, Xe Kong Province, Laos. Leptobrachium buchardi FMNH 258080-90, Champasak Province, Laos. Leptobrachium chapaense FMNH 258065, 258067-71, Bolikhamxay Province, Laos. Leptobrachium hendricksoni FMNH 178260-61, paratypes, Pahang, Malaysia. Leptobrachium pullum FMNH 196015, syntype, Annam, Vietnam. Leptobrachium smithi FMNH 172661-62, 173973-75, Chiang Mai, Thailand; FMNH 263263, Vientiane Province, Laos; FMNH 258091-92, 258097, 258101-06, Sayaboury Province, Laos. Leptobrachium xanthospilum FMNH 252914, 252920, Gia Lai Province, Vietnam. Additional data on L. banae and L. xanthospilum taken from original description ( Lathrop et al., 1998), on L. buchardi taken from original description ( Ohler et al., 2004), on L. chapaense taken from Lathrop et al. (1998), on L. hendricksoni taken from original description ( Taylor, 1962), on L. pullum taken from original description ( Smith, 1921) and Matsui et al. (1999), and on L. smithi taken from original description ( Matsui et al., 1999). Complete data on L. hasseltii taken from Dubois and Ohler (1998), Iskandar (1998), and Matsui et al. (1999).

Etymology. – The specific epithet is a patronym honoring Henri Mouhot (1826-1861), French explorer, naturalist, and earliest scientific collector of amphibian and reptile specimens in hilly eastern Cambodia.

Diagnosis. – A Leptobrachium having males with SVL 51.6- 64.7 and female 70.2; eye black with a narrow, orange-red crescent on outer margin from the anterior corner over the eye to lower rear corner; uniform dark gray dorsum; flank gray with small light spots; venter gray or brown with small light spots.

Description of holotype. – Habitus moderately stocky; head wider than long. Snout rounded in dorsal view, slightly projecting beyond lower jaw in profile; nostril closer to tip of snout than to eye; canthus rostralis distinct, constricted behind nostrils; lores oblique, slightly concave; diameter of eye less than length of snout; interorbital distance much greater than width of upper eyelid; tympanum round, weakly visible, slightly elevated relative to skin of temporal region, diameter smaller than that of the eye, diameter greater than the distance between the tympanum and eye; no pineal ocellus; large, slit-like vocal sac openings on floor of mouth; no nuptial pad.

Tips of all fingers blunt, not swollen; relative finger lengths II = IV <I <III; two oval palmar tubercles in contact, low callous bumps on ventral surface of fingers; no finger webbing. Tips of toes blunt, slightly swollen; relative toe lengths I <II <V <III <IV; webbing on toe I to base of tip, on preaxial side of toe II to toe articulation, on postaxial side of toe II to base of tip, on preaxial side of toe III to level of proximal subarticular tubercle continuing as a fringe to base of tip, on postaxial side of toe III to midway between proximal subarticular tubercle and tip continuing as a fringe to base of tip, on preaxial and postaxial sides of toe IV to level of tip of toe V continuing as a fringe to base of tip, and on toe V to midway between base and tip; a distinct, oval inner metatarsal tubercle, no outer metatarsal tubercle; heels non-overlapping when legs are held at right angles to body.

Skin on dorsum and dorsal surface of forelimbs smooth with fine network of ridges; skin on dorsal surface of hindlimbs smooth; skin on flank, chin, belly, and ventral surface of thigh with dense, small glandular warts; skin on ventral surface of forelimbs and tibiotarsus smooth; large oval axillary gland on ventrolateral surface slightly posterior to insertion of forelimb with body; distinct, whitish, round femoral gland on posteroventral surface of thigh, closer to knee than vent.

Colour of holotype in life. – Dorsum uniform dark gray-black, with three scattered round gray spots on back near groin; flank dark gray with small, scattered white spots, usually on warts; dorsal surface of forelimb and tibiotarsus with dark gray bands; anterior and dorsal surface of thigh with silver-copper bands; eye black with a narrow, orange-red crescent on outer margin from the anterior corner over the eye to lower rear corner (orange-red colouration visible only in posterior corner of eye in relaxed living animal, remainder visible when upper eyelid is maximally retracted); black spot at anterior and posterior corner of eye and on tympanum; chin, chest, belly and ventral surface of thigh gray with small light gray spots on warts, gray darkening posteriorly; ventral surface of forelimb and tibiotarsus dark gray with distinct light gray marbling.

Colour of holotype in preservative. – Dorsum and dorsal surface of limbs uniform dark gray, with three scattered round gray spots on back near groin; flank dark gray with small, scattered white spots, usually on warts; grayish-brown crossbars on anterior surface of thigh and anterior and posterior surface of tibia; eye gray-blue with a narrow, light orange crescent bordered with black on outer margin from the anterior corner over the eye to lower rear corner (visible only by retracting upper eyelid); black spot at anterior and posterior corner of eye and on tympanum; ventral surface grayish-brown with small creamy-white spots on warts, concentrated anteriorly, some larger creamy-white spots on chest; grayish-brown marbling on ventral surface of forelimb and tibia; axillary and femoral glands creamy-white.

Measurements. – Holotype: SVL 64.0, HDL 24.7, HDW 28.1, SNT 11.8, EYE 7.1, IOD 9.5, TIB 23.0, IML 3.6, IMW 1.5.

Variation. – Black spots or streak below edge of canthus in some paratypes. The scattered round gray spots on back near groin are present only in two other specimens, but in different locations on the back. Ventral pigmentation is more brown than gray in some paratypes. Measurements of paratypes summarized in Table 3.

Comparisons. – Four other species of Leptobrachium have reddish (orange, red, or scarlet) eye colouration: L. hasseltii Tschudi, 1838 , L. hendricksoni Taylor, 1962 , L. pullum ( Smith, 1921) , and L. smithi Matsui, Nabhitabhata & Panha, 1999 . Leptobrachium mouhoti differs from L. hasseltii by having a uniform dark gray dorsum (discrete dark rounded spots on dorsum in L. hasseltii ) and lacking longitudinal rows of ridges on hindlimb (present in L. hasseltii ). Leptobrachium mouhoti differs from L. hendricksoni by having males with SVL 51.6-64.7 (male L. hendricksoni 45-46), having a dark gray dorsum (lavender-brown dorsum in L. hendricksoni ), and having the venter gray or brown with small light spots (venter white with small black spots in L. hendricksoni ). Leptobrachium mouhoti differs from L. pullum by having males with SVL 51.6-64.7 and female 70.2 (male L. pullum 44.4-47.0, female L. pullum 49.4-52.8) and having orange-red eye colouration restricted to a narrow crescent on the anterior, dorsal, and posterior outer margins of eye (upper half of iris scarlet in L. pullum ). Leptobrachium mouhoti differs from L. smithi by having a uniform dark gray dorsum (large dark dorsal markings in L. smithi ), having the flank dark gray with small, scattered white spots (flank with distinct dark spots in L. smithi ), and having orange-red eye colouration restricted to a narrow crescent on the anterior, dorsal, and posterior outer margins of eye (upper half of iris scarlet or yellow in L. smithi ).

An additional four species of Leptobrachium occur in parts of Laos and Vietnam near to eastern Cambodia: L. buchardi Ohler, Teynié & David, 2004 , L. banae Lathrop, Murphy, Orlov & Ho, 1998 , L. chapaense (Bourret, 1937) , and L. xanthospilum Lathrop, Murphy, Orlov & Ho, 1998 . Leptobrachium mouhoti differs from L. buchardi by having a narrow orange-red crescent on the anterior, dorsal, and posterior outer margins of eye (upper part of iris pale green in L. buchardi ), and having the female with SVL 70.2 (female L. buchardi 49.5). Leptobrachium mouhoti differs from L. banae by having gray and silver-copper bands on limbs (orange-red or red bands on limbs in L. banae ), and having a narrow orange-red crescent on the anterior, dorsal, and posterior outer margins of eye (dorsal half of iris and outer margin of eye white in L. banae ). Leptobrachium mouhoti differs from L. chapaense by having a narrow orange-red crescent on the anterior, dorsal, and posterior outer margins of eye (upper half of iris black, white, or sky blue in L. chapaense ). Leptobrachium mouhoti differs from L. xanthospilum by having males with SVL 51.6-64.7 and female 70.2 (male L. xanthospilum 62.8-73.4, female L. xanthospilum 83.2-84.8), having the flank dark gray with small, scattered white spots (flank with distinct large yellow spots in L. xanthospilum ), and having a narrow orange-red crescent on the anterior, dorsal, and posterior outer margins of eye (upper half of iris white in L. xanthospilum ).

Ecology. – Specimens were collected at night on leaf litter of the forest floor, often near streams. The species was frequently heard calling at night in June, November, and December, suggesting it calls year-round. FMNH 262754 was calling from a muddy depression under a 25 cm diameter rock 2.5 m from a wide, swift stream, and FMNH 261762 was calling from a depression under a log 4 m from a stream. FMNH 261760-61 were in amplexus at night while floating in a shallow, 3 m wide stream pool with sandy substrate.

Figures

Fig. 2. Eye of Leptobrachium mouhoti, new species, holotype male (FMNH 262756), in life.

Fig. 3. Dorsal view of Leptobrachium mouhoti, new species, holotype male (FMNH 262756), in preservative.