The Leptobrachium (Anura: Megophryidae) of the Langbian Plateau, southern Vietnam, with description of a new species Author Stuart, Bryan L. Author Rowley, Jodi J. L. Author Tran, Dao Thi Anh Author Le, Duong Thi Thuy Author Hoang, Huy Duc text Zootaxa 2011 2804 25 40 journal article 10.5281/zenodo.208159 4a75496d-334e-4342-b41c-aaef390cef90 1175-5326 208159 Leptobrachium leucops sp. nov. Holotype : NCSM 77465 (field tag BLS 11751; Figures 2 , 6 ), adult male, Vietnam , Langbian Plateau, Lam Dong Province, Lac Duong District, Bidoup-Nui Ba National Park, Hon Giao, 12°11'11.2"N 108°42'53.5"E ( Figure 7 ), 1,627 m elev., coll. 6 March 2008 by Bryan L. Stuart, Jodi J. L. Rowley, Tran Thi Anh Dao , Le Thi Thuy Duong, Hoang Duc Huy, Nguyen Le Xuan Bach, and Nguyen Thi Xuan Phuong. Paratypes : Fourteen adult males: AMS R173163, same data as holotype ; FMNH 280396 , NCSM 77463–64, NCSM 77467, UNS 00121/AMS R173159, UNS 00122/AMS R173160, UNS 00123/AMS R173161, AMS R173162, AMS R173165, UNS 00124/AMS R173166, AMS R173168, same data as holotype except coll. 4–16 March 2008 ; NCSM 77466, AMS R173164, Vietnam , Langbian Plateau, Khanh Hoa Province, Khanh Vinh District, 12°11'30.5"N 108°43'03.5"E , 1,558 m elev., coll. 8 March 2008 by Bryan L. Stuart, Jodi J. L. Rowley, Tran Thi Anh Dao , Le Thi Thuy Duong, Hoang Duc Huy, Nguyen Le Xuan Bach, and Nguyen Thi Xuan Phuong. Two immature females: UNS 00125/AMS R173167, same data as holotype except 12°11'33.3"N 108°42'41.6"E , 1,900 m elev., coll. 10 March 2008 ; AMS R173158, same data as holotype except 12°11'24.3"N 108°42'49.0"E , 1,751 m elev., coll. 19 May 2008 by Jodi J. L. Rowley, Tran Thi Anh Dao , Le Thi Thuy Duong, Hoang Duc Huy, Da Du Ha Tien, Vu Hanh Dung, Dinh Binh Phuong, Ly Tri, and Nguyen Thi Xuan Phuong. Etymology. The specific epithet taken from leukos Gr. for white and ops Gr. for eye, in reference to the iris color of the new species. Diagnosis. Assigned to the genus Leptobrachium on the basis of having head width larger than shank length; skin above with a network of ridges; large axillary glands; extremities of digits rounded; and upper part of iris colored differently from lower part ( Dubois & Ohler 1998 ). A small-sized Leptobrachium having males with SVL 38.8–45.2; upper one-third to one-half of iris white; blue scleral arc; dark venter (purplish-gray, dark gray, or black in life, dark gray in preservative) with minute white spots on tubercles; and sexually active males without spines on the upper lip. Description of holotype . Habitus moderately stocky; body tapering to groin. Head broad and depressed; head length and width subequal. Snout rounded in dorsal view, sharply sloping in profile, barely projecting beyond lower jaw in profile; nostril closer to tip of snout than to eye, below canthus, internarial shorter than interorbital distance; canthus rostralis distinct; lores oblique, moderately concave; eye large, slightly projecting from side of head, diameter subequal to snout length, interorbital distance subequal to upper eyelid width; no pineal ocellus; tympanum round, annulus weakly visible, tympanum diameter about 40% eye diameter and greater than distance between tympanum and eye; tongue heart-shaped, notched posteriorly; large, slit-like vocal sac openings on floor of mouth near lateral margin of tongue; vomerine teeth absent. Forelimb slender. Fingers moderately slender, without webbing. Tip of fingers blunt, those on fingers I and II slightly swollen; relative finger lengths II = IV<I<III; two oval palmar tubercles in contact, inner larger than outer, low callous bumps on ventral surface of fingers; nuptial pad absent. Hindlimb slender and relatively short. Toes moderately slender; webbing on toe I and preaxial side of toe II to level of distal margin of subarticular tubercle, 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 same level as postaxial side of toe III and continuing as a fringe to base of tip, and on toe V to midway between base and tip. Tips of all toes blunt, slightly swollen; relative toe lengths I<II<III = V<IV; distinct, oval, inner metatarsal tubercle, length about 70% distance between tip of toe I and tubercle; no outer metatarsal tubercle. Skin above smooth with fine network of ridges, with small granules scattered posteriorly, especially near vent; no spines on upper lip; low supratympanic ridge from posterior edge of eye to axilla; ventrally granular, skin smooth on ventral surfaces of limbs; large, round axillary gland on ventrolateral surface slightly posterior to insertion of forelimb with body; oval femoral gland on posteroventral surface of thigh, midway between knee and vent. Color of holotype in life. Dorsum dark gray, with distinct dark brown, Y-shaped marking extending from upper eyelids to lower back, becoming narrower posteriorly, edged with cream, with smaller, irregular dark brown to black markings edged with cream on lower back; upper flank with irregular dark brown and black markings edged with cream or white, lower flank dark gray with minute white spots on tubercles; upper surface of forelimb brown with dark gray bands, each flanked with narrower cream bands; upper surface of hindlimb white or creamywhite with dark grey and black bands; eye black with upper one-third of iris white, scleral arc blue (visible in the posterior corner of the eye and when the palpebrum is retracted); brown bar from edge of upper lip to nostril and from edge of upper lip to lower margin of eye; irregular, black streak under canthus and supratympanic fold, covering tympanum; ventral surface of body and limbs purplish-gray to dark gray, black spotting on chin, minute white spots on tubercles on chin, chest, belly, and banding from upper surfaces of limbs extending to outer margins of lower surfaces of limbs; axillary and femoral glands creamy-white. Color of holotype in preservative. Color in preservative closely resembles color in life, except that cream on dorsal surfaces has faded to white or gray, and purplish-gray on ventral surfaces has faded to dark gray. FIGURE 2. (A) Lateral and (B) frontal views of the male holotype (NCSM 77465), (C) lateral view of male paratype UNS00123/AMS R173161, (D) lateral view of male paratype AMS R173163, and (E) ventral view of male paratype NCSM 77463 of Leptobrachium leucops sp. nov. (previously as “white-eyed” form) in life. FIGURE 3. (A) Lateral view of head, (B) dorsal view, and (C) ventral view of the lectotype male (BMNH 1921.5.5.36) of Leptobrachium pullum in preservative. Measurements of holotype . SVL 41.2; HDL 19.8; HDW 19.5; SNT 7.0; EYE 7.6; IOD 5.3; IND 4.1; SHK 14.6; TGH 18.3; LAL 13.2; HND 9.7; FTL 15.6; IML 2.0; IMW 1.5. Variation. The dorsal pattern is highly variable among paratypes ( Figure 2 ). The background color of the dorsum in life varied from brown to light gray to dark gray. The darker markings on the dorsum are variable in size and shape. One (AMS R173165) has the dark markings on back arranged as rounded spots ( Figure 6 ). Some (AMS R173158, UNS00121/AMS R173159, UNS00123/AMS R173161, AMS R173162–64, NCSM 77463, NCSM 77467) have a uniform dark gray dorsum with few or no darker markings ( Figure 6 ). Three paratypes (AMS R173165, UNS00124/AMS R173166, AMS R173168) have more distinct limb banding in preservative than the holotype . The ventral coloration is dark gray to black in some paratypes , and some lack black spotting on the chin. The white coloration in the eye extends to about one half of the iris in some paratypes . Measurements are summarized in Table 1 . Advertisement call. The following description is based on the calls of five individuals recorded at 13.0– 18.4°C ( Table 4 ). The call contains 1–5 (but usually 3–4), highly-pulsed notes and lasted 0.10– 1.70 s, repeated at a variable interval (6.5– 124.1 s). Within a call, notes were relatively evenly spaced and each note contained 8–15 pulses repeated at a near constant rate across the call. Relative amplitude varied symmetrically within each note, gradually rising over the first half of each note and then declining gradually across the second half of the note (Figure 5). The dominant frequency of calls varied from 1.0–1.6 kHz, and spanned approximately 1 kHz ( Figure 5 ). A low frequency band was present at around 0.2 kHz, and a weak harmonic was present at approximately 2.6 kHz. There was slight frequency modulation within each note, with the first few pulses and occasionally the last few pulses approximately 0.1 kHz lower in frequency. Temporal and spectral properties of the call did not obviously vary with temperature in the five specimens recorded ( Table 4 ). To the human ear, the call sounds like a rapid barking “wah-wah-wah-wah”. FIGURE 4. Advertisement call of a male Leptobrachium pullum (NCSM 77462; previously as “red-eyed” form) recorded at ambient air temperature of 20.4ºC (A) 40 s waveform of relative amplitude, (B) an expanded waveform, and (C) corresponding spectrogram showing a single representative call, and (D) a power spectrum (relative amplitude vs. frequency). Distribution and natural history. Leptobrachium leucops is known only from 1,558–1,900 m elevation on the Langbian Plateau in Lam Dong and Khanh Hoa Provinces, Vietnam . The species occurs in wet evergreen and cloud forest, where males call from shallow burrows under leaf litter. Leptobrachium leucops occurs in syntopy with L. pullum at some sites; in March, males of both species were heard calling within a few meters of each other. Comparisons. Only two other named species of Leptobrachium that occur in Vietnam , Laos , or Cambodia (Table 2) have the upper part of the iris white: L. banae Lathrop, Murphy, Orlov & Ho, 1998 and L. xanthospilum Lathrop, Murphy, Orlov & Ho, 1998 . Both species are restricted to the Kon Tum Plateau of Vietnam ( Lathrop et al . 1998 ), the nearest uplands to the Langbian Plateau ( Figure 7 ). However, both are considerably larger than the new species, with SVL of males in L. xanthospilum 62.8–73.4 and L. banae 57.2–70.0 ( 38.8–45.2 in L. leucops ). Leptobrachium xanthospilum further differs by having distinct, large, yellow, glandular spots on the flank (absent in L. leucops ). Leptobrachium banae further differs by having red bands on the limbs (absent in L. leucops ) and a white scleral arc (blue in L. leucops ). Leptobrachium chapaense ( Bourret, 1937 ) has been reported to have a black iris (upper and lower parts not differing) or the upper part of the iris white or blue ( Dubois & Ohler 1998 ; Lathrop et al. 1998 ). Molecular evidence suggests that L. chapaense is actually a complex of species across its range ( Rao & Wilkinson 2008 ); at its type locality at Sa Pa in northwestern Vietnam , the eyes are black ( Bourret, 1937 ; Orlov, 2005 ). Leptobrachium “ chapaense ” at Tam Dao , northern Vietnam , has a white upper iris, but is larger than the new species, with SVL of males 53.5–65.5 ( 38.8–45.2 in L. leucops ), and has orange blotches on the sacral region, flank, and dorsal surfaces of limbs (absent in L. leucops ; Lathrop et al . 1998 ). The eye color of L. ngoclinhense ( Orlov, 2005 ) , unreported in its original description ( Orlov, 2005 ), is dark brown to black (no light-colored upper iris) with a white scleral arc (J. J. L. Rowley, unpublished). TABLE 4. Call parameters of Leptobrachium leucops sp. nov. (previously as “white-eyed” form). Parameter values are given as means (ranges). An asterisk (*) refers to the individual in Figure 5. Parameter Individual