Leptolalax minimus (Taylor, 1962)

Anh Van Pham, Dzung Trung Le, Cuong The Pham & Son Lan Hung Nguyen, 2016, Two additional records of megophryid frogs, Leptobrachium masatakasatoi Matsui, 2013 and Leptolalax minimus (Taylor, 1962), for the herpetofauna of Vietnam, Revue suisse de Zoologie 123 (1), pp. 35-43 : 40-42

Leptolalax minimus (Taylor, 1962)

Small Asian Toad

Fig. 4

Leptobrachium minimum Taylor, 1962: 320 .

Leptolalax (Lalos) minimus . – Delorme, Dubois, Grosjean &

Ohler, 2006: 67.

Material examined (n = 10): TBU PAE.493; 1 adult male; near Hua Ty Village, 21°20.866’N, 103°34.948’E, elevation 1390 m a.s.l., Co Ma Commune, within Copia NR; 22 July 2013; collected by A. V. Pham and T. V. Nguyen. ‒ TBU PAE.566; 1 adult female; near Kha Village, 21°00.365’N, 103°25.913’E, elevation 1190 m a.s.l., Pung Banh Commune, within Sop Cop NR; 2 March 2014; collected by A. V. Pham and D. A. Vi. ‒ IEBR A.2015.20; 1 adult male; near Kha Village, 21°00.365’N, 103°25.913’E, elevation 1190 m a.s.l., Pung Banh Commune, within Sop Cop NR; 20 September 2014; collected by T. Q. Nguyen, A. V. Pham, H. N. Ngo, T. V. Nguyen, H. V. Tu. ‒ MHNG 2749.9; 1 adult female; near Kha Village, 21°00.365’N, 103°25.913’E, elevation 1190 m a.s.l., Pung Banh Commune, within Sop Cop NR; 21 September 2014; collected by T. Q. Nguyen, A. V. Pham, H. N. Ngo, T. V. Nguyen, H. V. Tu. ‒ HNUE MNA.159; 1 adult female; Suoi Do stream, near Nam San village, 22°12.050’N, 102°20.483’E, elevation 1370 m a.s.l., within Muong Nhe NR; 18 February 2013; collected by D. T. Le and H. P. Vu. ‒ HNUE MNA. 335; 1 adult female; Suoi Do stream, near Nam San village, 22°12.050’N, 102°20.483’E, elevation 1370 m a.s.l., within Muong Nhe NR; 22 March 2014; collected by D. T. Le and H. P. Vu. ‒ IEBR A.2015.21; 1 adult male; Hang Doi mountain, near Nam Po village, 22°09.017’N, 102°26.533’E, elevation 910 m a.s.l., within Muong Nhe NR; 11 September 2014; collected by T. Q. Nguyen, D. T. Le, C. T. Pham, and H. N. Ngo. ‒ IEBR A.2015.22, MHNG 2749.10); 2 adult females; Hang Doi mountain, near Nam Po village, 22°09.017’N, 102°26.533’E, elevation 910 m a.s.l., within Muong Nhe NR; 11 September 2014; collected by T. Q. Nguyen, D. T. Le, C. T. Pham, and H. N. Ngo. ‒ IEBR A.2015.23; one adult female; Mu stream, Tu Do Commune, 20°41.597’N, 105°22.107’E, elevation 313 m a.s.l., within Ngoc Son- Ngo Luong NR; 4 October 2014; collected by C. T. Pham and H. N. Ngo.

Description: Morphological characters of specimens from Vietnam agreed well with the descriptions of Taylor (1962) and Ohler et al. (2011): SVL 26.0- 29.3 mm in males (mean ± SD 27.3 ± 1.7 mm, n = 3) and 32.7-38.0 mm in females (mean ± SD 34.2 ± 1.7 mm, n = 7) (Table 1).

Head longer than wide (HL 9.9-10.9 mm, HW 8.8- 10.0 mm, HL/SVL 47.0-38.0%, HW/SVL 34.0% in males; HL 12.5-15.0 mm, HW 11.4-14.1 mm, HL/SVL 37.0-39.0%, HW/SVL 33.0-37.0% in females); snout protruding, longer than eye diameter (SL 3.5-4.1 mm, EL 3.1-4.0 mm in males; SL 4.5-5.3 mm, EL 4.3-4.9 mm in females); nostrils oval, on lateral side, closer to the tip of snout than to eye (NS 1.3-1.5 mm, EN 1.6-2.1 mm in males; NS 1.6-2.2 mm, EN 2.4-3.5 mm in females); canthus rostralis distinct, loreal region concave; interorbital distance wider than upper eyelid width and internarial distance (IUE 2.8-3.3 mm, UEW 2.6-2.9 mm, IN 2.5-2.9 mm in males; IUE 3.5-4.3 mm, UEW 3.2- 4.1 mm, IN 3.0-4.0 mm in females); eye large, pupil vertical; tympanum round, distinct ( TYD 1.7-2.0 mm in males and 2.0- 2.8 mm in females), greater than distance to posterior corner of eye (TYE 1.3-1.5 mm in males and 1.4-2.2 mm in females); vomerine teeth absent; tongue notched posteriorly.

Forelimb: Forearm rather thin (LAL 6.9-7.6 mm in males, 8.0-11.0 mm in females), longer than hand (HAL 6.3- 6.7 mm in males; HAL 7.8-10.0 mm in males); relative finger lengths I<II<IV<III, tips of fingers not enlarged into discs; fingers free of webbing; subarticular tubercles distinct, 1:1:2:2; palmar tubercles round, in contact with each other, inner one very large.

Hindlimb: Thigh short (FL 11.7-13.9 mm in males and 15.0- 19.4 mm in females); tibia three times longer than wide (TL 12.0- 14.3 mm, TW 3.3-3.5 mm in males; TL 14.4-18.3 mm, TW 3.0- 4.5 mm in females); relative toe lengths I<II<V<III<IV; webbing rudimentary between toes I and II and between IV and V, slightly developed between toes II and III, III and IV, webbing formula I1– 1II1– 2 ½ III2–3IV3– 2 V, dermal fringes well developed but absent along outer edge of toe V; subarticular tubercles round, indistinct, 1:1:2:3:2; inner metatarsal tubercle prominent; outer metatarsal tubercle absent. Skin. Dorsal head smooth, dorsum and upper part of flanks with tubercles and glandular folds; supratympanic fold distinct; dorsolateral fold absent; dorsal surface of limbs with tubercles and glandular folds; ventral surface smooth.

Coloration in life. Upper part of iris dark golden, lower part grey; dorsal surface of head and body brown grey with a triangular marking between eyes, some grey spots in middle of back; dorsolateral region with some small dark spots; dorsal surface of fore and hindlimbs brown grey with dark bars; tympanic region dark brown; upper lip brown with dark bars; posterior part of thigh dark brown with white spots and a large femoral gland on each side; throat and chest transparent grey; border of throat grey with white spots; belly white.

Remarks: The female specimens from Vietnam are slightly larger than those from Thailand and Laos (SVL 32.7-38.0 mm versus 31.6-37.3 mm) (see Ohler et al., 2011).

Ecological notes: Specimens of L. minimus were collected between 19:00 and 22:00 on stones at stream banks or on leaves, about 0.3-0.6 m above the forest floor, near rocky streams. The surrounding habitat was mixed evergreen forest or secondary forest of small hardwood, bamboo and shrub.

Distribution: This species was previously known only from Thailand and Laos (Ohler et al., 2011).

Figures

Fig. 4. Leptolalax minimus (IEBR A. 2015.22) from Dien Bien Province, Vietnam. (a) dorsolateral view. (b) ventral view. Photos T. Q. Nguyen.