Leptolalax minimus Taylor 1962

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).