Leptobrachium pullum ( Smith, 1921 )

Stuart, Bryan L., Rowley, Jodi J. L., Tran, Dao Thi Anh, Le, Duong Thi Thuy & Hoang, Huy Duc, 2011, The Leptobrachium (Anura: Megophryidae) of the Langbian Plateau, southern Vietnam, with description of a new species, Zootaxa 2804, pp. 25-40 : 30-32

Leptobrachium pullum ( Smith, 1921)

Megalophrys hasseltii var. pullus Smith, 1921: 440 .

Expanded description. The adult male lectotype (BMNH 1921.5.5.36; Figure 3 ) in preservative has a conspicuous, white scleral arc under palpebrum extending from anterior corner of eye at approximately 90° (in right eye), continuing as narrow strip to approximately 270°, becoming wider to its terminus at approximately 240°, visible only in posterior corner of eye when palpebrum is relaxed, covering approximately upper 1/5 of iris. Large, slit-like vocal sac openings on floor of mouth near lateral margin of tongue. Tympanic annulus scarcely visible. Dorsum brown with dark spots over some tubercles, without large, dark markings. Black streak under canthus and supratympanic fold, covering tympanum. Whitish bands on dorsal and anterior surfaces of thigh, posterior surface of shank, and dorsal surface of tarsus, weaker whitish bands on dorsal surface of forelimb, anterior surface of shank, and axial surface of tarsus. Large, whitish spots on flank, more on right side. Venter beige with white spots on tubercles, lighter than dorsum, without darker markings. Ventral surface of thigh darker than belly, with white spots on tubercles. SVL 48.0; HDL 20.7; HDW 20.9; SNT 8.5; EYE 7.1; IOD 6.3; IND 4.2; SHK 16.9; TGH 18.7; LAL 14.2; HND 11.7; FTL 17.9; IML 2.7; IMW 1.4.

Five adult males (NCSM 77458–62) from Bi Doup-Nui Ba National Park, Lac Duong District, Lam Dong Province, Langbian Plateau, Vietnam, have habitus moderately stocky; body tapering to groin. Head broad and depressed; head length and width subequal. Snout rounded or very obtusely pointed in dorsal view, sharply sloping in profile, barely projecting beyond lower jaw in profile; nostril about midway between tip of snout and 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 or moderately visible, tympanum diameter about 50% 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, subequal in size, low callous bumps on ventral surface of fingers; nuptial pad absent.

Hindlimb slender and relatively short. Toes moderately slender; webbing on toes I and II to level of distal margin of subarticular tubercle and continuing as a fringe to base of tip, on preaxial side of toe III to level of distal margin of proximal subarticular tubercle continuing as a fringe to base of tip, on postaxial side of toe III to midway between proximal and distal subarticular tubercles continuing as a fringe to base of tip, on toe IV to level of proximal subarticular tubercle 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<V<III<IV; distinct, oval, inner metatarsal tubercle, length about 90% distance between tip of toe I and tubercle; no outer metatarsal tubercle.

Skin above smooth with fine network of ridges; no spines on upper lip; low supratympanic ridge from posterior edge of eye to axilla; ventrally granular, skin smooth on ventral surfaces of limbs; indistinct, 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.

In life, dorsum dark brown, dark gray, or black, without distinct markings, some with small black spots on tubercles, some with small, scattered, light orange spots; upper flank like dorsum, lower flank like belly; upper surface of forelimb and hindlimb as dorsum, with light gray bands, some with light orange wash over gray bands; eye black with scarlet scleral arc as described in lectotype (visible in the posterior corner of the eye and when the palpebrum is retracted); no lip bars; narrow black streak under canthus and supratympanic fold, sometimes covering tympanum; chin and belly whitish-gray with dark gray spotting, spotting denser posteriorly; ventral surface of limbs black with silver-white bands. In preservative, closely resembles color in life, except that scleral arc has faded to light orange, and light orange spotting and wash on dorsal surfaces has faded to white or creamy-white. Measurements are summarized in Table 1 .

Parameter Voucher

Advertisement call. The following description is based on the calls of five individuals recorded at 13.3– 20.4°C ( Table 3 ). The call contains a single, highly-pulsed note lasting 0.25– 0.46 s, and repeated relatively infrequently (7.0– 60.9 s intercall interval). Each call contained approximately 30 pulses repeated at a near constant rate across the call. Relative amplitude across each call was heterogeneous, with a low and steadily increasing amplitude peaking about two-thirds of the way, followed by a more rapid decline in amplitude ( Figure 4 ). The dominant frequency of calls varied from 1.0–1.3 kHz, and spanned approximately 1 kHz. A low frequency band was present at around 0.2 kHz, and harmonics were present at approximately 2.4, 3.6, and 5.1 kHz ( Figure 4 ). There was no frequency modulation. Temporal and spectral properties of the call (but not overall structure) may vary with temperature, as call duration, intercall interval, pulse repetition rate and dominant frequency were considerably lower at 13.3°C compared to 18.4–20.4°C ( Table 3 ). To the human ear, the call sounds like a slow, deep bark “waaaaah”.

Distribution and natural history. We sampled L. pullum from 1,477–1,724 m elevations on the Langbian Plateau in Lam Dong and Khanh Hoa Provinces, Vietnam. The taxonomic identity of red-eyed Leptobrachium from elsewhere in southern Vietnam and Cambodia requires evaluation (below). On the Langbian Plateau, L. pullum occurs in wet evergreen and cloud forest, where males call from shallow burrows under leaf litter. Leptobrachium pullum occurs in syntopy with L. leucops sp. nov. at some sites; in March, males of both species were heard calling within a few meters of each other.

Figures

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.

FIGURE 4. Advertisement call of a male Leptobrachium pullum (NCSM 77462; previously as “ red-eyed ” form) recorded at ambient air temperature of 20.4 ºC (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).

Tables

TABLE 3. Call parameters of Leptobrachium pullum (previously as “ red-eyed ” form). Parameter values are given as means (ranges). An asterisk (*) refers to the individual in Figure 4.

Call duration (s) 0.30 (0.29–0.32) Intercall interval (s) 18.7 (9.5–31.1) Call repetition rate 0.053	0.44 (0.41–0.46) 45.8 (30.7–60.9) 0.022	0.27 (0.25–0.29) 0.31 (0.27–0.33) 16.4 (7.0–42.1) 12.9 (7.3–16.0) 0.059 0.076	0.29 (0.28– 0.30) 13.6 (8.1–23.9) 0.072
Pulses/note (approx.) 40	33	27 35	32
Pulse repetition rate (approx.) 129 Dominant frequency (kHz) 1.3	72 1.1 (1.0–1.2)	97 111 1.1 1.3	105 1.3
Temperature 18.4	13.3	18.4 20.4	19.4