Leptobrachella namdongensis, Chung & Tao & Vinh & Truong & Jianping, 2019

Chung, Hoang Van, Tao, Nguyen Thien, Vinh, Luu Quang, Truong, Nguyen Quang & Jianping, Jiang, 2019, A new species of Leptobrachella Smith 1925 (Anura: Megophryidae) from Thanh Hoa Province, Vietnam, Raffles Bulletin of Zoology 67, pp. 536-556 : 551-555

Leptobrachella namdongensis , new species

(Figs. 3–5; Tables 2, 4)

Holotype. Adult male VNUF A.2017.37 (field number: ND2.17.37), VIETNAM: Thanh Hoa Province, Quan Hoa District, Nam Dong Commune , Nam Dong Conservation Area , 20°19′44.9″N, 104°55′05.7″E, 710 m a.s.l., in evergreen forest, Q. V. Luu et al. Coll., 13 July 2017.

Paratypes (n=6). Three adult females VNMN2019.04 (field number: ND.17.0176); IEBR 4512 (ND.17.0179); VNUF A.2017.95 (field number: ND.17.95), VIETNAM: Thanh Hoa Province, Quan Hoa District, Nam Dong Commune , Nam Dong Conservation Area , 20°19′17.3″N, 104°55′15.6″E, 740 m a.s.l., in evergreen forest, Q. V. Luu et al. Coll., 30 May 2017 . Three adult females VNUF A.2018.15 (field number: ND.18.15); VNMN2019.05 (field number: ND.18.14); IEBR 4513 (field number: ND.18.08), VIETNAM: Thanh Hoa Province, Quan Son District, Trung Thuong Commune , Nam Dong Conservation Area , 20°18′211″N, 104°54′349″E, 589 m a.s.l., in evergreen forest, Q. V. Luu et al. Coll. 14 April 2018 .

Diagnosis. Leptobrachella namdongensis , new species is distinguished from its congeners by a combination of the following morphological characters: size medium (30.9 mm in the adult male and 32.1–35.3 mm in adult females); head wider than long; tympanum distinct; throat immaculate white, chest and belly with dark specking on outer margins; toes with basal webbing and without lateral fringe; supratympanic fold edged by a distinct black line; inter-orbital region with A B C

Fig. 5. Lateral view of the head (A), right food (B) and right hand (C) of the holotype (VNUF A.2017.37) of Leptobrachella namdongensis , new species.

distinct black blotches; iris bicoloured, upper half copper, fading to golden in its lower half; head without dorsolateral markings.

Description of holotype. Habitus stocky. Size medium, head wider than long (HDL/HDW 0.92); snout obtusely pointed in dorsal view, slightly projecting beyond margin of lower jaw; nostril round, located closer to tip than to eye; canthus rostralis round; loreal region sloping; pupil vertical; eye diameter equal to snout length (EYE/SNT 0.92); tympanum distinct, round, tympanum diameter smaller than (48%) that of eye; tympanic rim not elevated relative to skin of temporal region; vomerine teeth absent; pineal ocellus absent; vocal sac openings present, located on either side of floor of mouth; tongue large, broad, with small notch at tip; supratympanic fold forming a distinct ridge, running from posterior corner of eye towards axillary gland; supratympanic ridge not smooth with few nodule (Fig. 5A). Forelimbs thin, slender; finger tips round, not broader than phalange width; relative finger lengths: I <II = IV <III; nuptial pad absent; subarticular tubercles absent; a large, round inner palmar tubercle, distinctly separated from small, laterally compressed outer palmar tubercle; finger webbing absent and weak dermal fringes (Fig. 5C). Hindlimbs slender, tibia nearly half of snout-vent length (TIB/SVL 0.51). Tips of toes like those of fingers; relative toe lengths: I <II <V <III <IV; subarticular tubercles absent, replaced by distinct dermal ridges; inner metatarsal tubercle small, oval, pronounced, outer metatarsal tubercle absent; webbing rudimentary between toes I–IV, absent between toes IV–V; toes with very weak lateral fringing (Fig. 5B). Skin texture in life; skin on entire dorsum with low, round tubercles, more dense in posterior part of the back; dorsal surface of thighs, upper arms and upper eyelid covered by small tubercles; ventral skin smooth; pectoral gland laterally compressed, 0.8 mm in diameter; femoral glands small, oval, approximately 1.1 mm in diameter, located on posteroventral surfaces of thighs, closer to knee than to vent; supra-axillary gland raised, 0.8 mm in diameter. Ventrolateral glands present, dorsolaterally compressed forming an incomplete line (Fig. 3).

Colouration in life (Fig. 3). Dorsum brown with grey markings, flanks and heels light-brown with some dark flecks; interorbital region with a dark bar; a W-shaped marking between axillae, an inverted V-shaped marking between sacrum; upper lip with dark brown bars; loreal and tympanic region with distinct dark brown markings, a dark brown stripe below supratympanic ridge, running from posterior corner of eye towards tympanum; dorsal surface of limbs with diffuse, transverse dark brown bars; fingers and toes with faint transverse bars; throat, chest and belly opaque white; outer edges of chin, thighs, arms and all of tibiotarsus brownish grey with small whitish spots; supraaxillary gland light-brown; femoral, pectoral and dorsolateral glands white; iris bicoloured, copper in upper half, fading to golden in its lower half.

Colouration in preservative. Dorsal surface grey; throat, chest and belly white; ventrolateral margins of throat and belly with brown speckling; ventral surface of thighs and arms cream to pale brown with white speckling; white macro glands and pectoral glands became indistinct in preservative ( Fig. 4 ).

Variation. Measurements of the type series are shown in Table 3 and photographs of paratypes in life are shown in Fig. 6 . Specimens vary in body size and colour pattern in life. Glands around cloacal opening vary in size and number. Tuberculation is more distinct in the male than in the females. In preservative dorsal skin texture varies from finely tuberculate (VNUF A.2017.37) to almost smooth (VNUF A.2017.95, VNMN2019.04, IEBR 4512, VNUF A.2018.15, VNMN2019.05, and IEBR 4513). Females are larger in body size (SVL 32.1–35.3; n=6) compared to the male holotype (SVL 30.9; n=1).

Etymology. Specific epithet is in reference to the type locality of the Nam Dong Conservation Area. We recommend “Nam Dong litter frog” as the common English name and “Cóc mày nam động” as the Vietnamese name.

Distribution and ecological notes. Leptobrachella namdongensis , new species is currently known from Nam Dong Conservation Area and Pu Hu Nature Reserve (NR), Thanh Hoa Province, Vietnam. All specimens of the new species were found on rocks in small streams or near cascade streams in evergreen forest at elevations between 500 and 740 m a.s.l. ( Fig. 7 ). Leptobrachella namdongensis , new species occurs sympatrically with Leptobrachella ventripunctata .

Figures

Fig. 4. Lateral view (A) and ventral view (B) of the holotype (VNUF A.2017.37) ofLeptobrachella namdongensis, new species in preservative.

Fig. 6. Paratypes of Leptobrachella namdongensis, new species in life. A, femaleVNUF A.2017.95 (SVL 32.1mm); B, female VNMN2019.04 (SLV 33.0mm); C, female IEBR 4512 (SVL 32.2mm). Photos by Vinh Q. Luu.

Fig. 7. Habitat of Leptobrachella namdongensis, new species in Nam Dong Conservation Area, Thanh Hoa Province, Vietnam.