Leptobrachella weixinensis Liu, Chen, Xu & Wu, 2025, sp. nov.

Leptobrachella weixinensis sp. nov. Figs 3, 4, Table 1 Holotype. • NNU 040615, an adult male collected from Shizigou village, Zhaxi Town, Weixin County, Zhaotong, Yunnan Province, China (27.84730 ° N, 105.02633 ° E; elevation 1280 m a. s. l.), collected by Lu Chen on 15 June 2024. Paratypes. • Two males, NNU 040602 and NNU 040603, collected at the same locality and with same collection information as the holotype. Etymology. The specific epithet “ weixinensis ” is given as a noun in apposition and refers to the name of the Weixin County in Yunnan Province, China, where the new species occurs. We suggest the English common name “ Weixin Leaf Litter Toad ” and the Chinese common name “ 威信掌突蟾 ” (Wēi Xìn Zhǎng Tū Chán). Diagnosis. Leptobrachella weixinensis sp. nov. is assigned to the genus Leptobrachella morphologically by the presence of small size, presence of macroglands (supra-axillary, femoral, and ventrolateral glands), vomerine teeth absent, rounded finger tips, and presence of an elevated inner metacarpal tubercle not continuous to the thumb (e. g., Dubois 1980; Ohler et al. 2011; Rowley et al. 2013). The new species can be further distinguished from its congeners by the combination of: (1) small body size (SVL 28.2–29.7 mm in three males); (2) interorbital space wider than internarial distance; (3) upper margin of tympanum incontact with supratympanic ridge; (4) tibiotarsal articulation reaches the nostril when hindlimb is stretched along the side of the body; (5) heels overlapping; (6) toes with rudimentary webbing and narrow lateral fringes; (7) flanks with large irregular black spots; (8) iris distinctly bicolored, typically orange in upper half, silver white in lower half; (9) ventral surface of throat, chest, and belly creamy white; chest and abdomen with distinct dark patches; (10) supratympanic ridge distinct with reddish-brown pigmentation. Description of holotype (Table 1). NNU 040615, sexually mature male, body size small, SVL 28.2 mm; head length (HDL 10.0 mm) almost equal to head width (HDW 10.1 mm); head triangular in dorsal view; snout short (SNT / HDL 38.0 %), snout round in both dorsal view and profile, projecting beyond margin of lower jaw (Fig. 3 A, B); oval-shaped nostril closer to tip of snout than to anterior margin of eye; canthus rostralis indistinct; loreal region slightly concave; eyes large (ED / HDL 36.0 %), protuberant in both dorsal and lateral views; eye diameter twice of the maximum tympanum diameter (TD / ED 200 %) and subequal to snout length (ED / SNT 94.7 %); tympanum distinct, rounded, tympanic ring slightly elevated relative to skin of temporal region (Fig. 3); upper margin of tympanum incontact with supratympanic ridge; eye-tympanum distance less than twice as long as maximum tympanum diameter (TED / TD 55.6 %); pupil vertical; interorbital space (IOD 3.3 mm) flat, wider than internarial distance (INS 2.4 mm) and width of upper eyelid (UEW 2.8 mm); vomerine teeth absent; tongue with shallow notch at posterior tip; vocal sac openings slit-like, paired, located posterolaterally on floor of mouth; supratympanic ridge distinct with reddish-brown pigmentation, extending from posterior corner of eye to supra-axillary gland, the posterior end of supratympanic ridge not expanded (Fig. 3). Forelimb relatively long, forearm shorter than hand, not enlarged (FAL 7.3 mm, HL 7.6 mm); fingers slender, relative finger lengths: I = IV <II <III; tips of fingers rounded, slightly swollen; subarticular tubercles absent on fingers; supernumerary tubercles absent; webbing between fingers absent; inner metacarpal tubercle large and rounded, separated from the smaller, round outer metacarpal (Fig. 3 E). Hindlimbs relatively long; thigh length greater than tibia length (TL / THL 92.4 %) and foot length (FL / THL 95.8 %); tibiotarsal articulation reaches the nostril when hindlimb is stretched along the side of the body; heels overlapping when thighs are positioned at right angles to the body; relative toe lengths: I <II <V <III <IV; tips of toes rounded, slightly swollen; subarticular tubercles distinct under the base of I, II, III, and IV toes; rudimentary webbing between toes; narrow lateral fringes present on all toes; inner metatarsal tubercle elongated (IMTL 1.4 mm, 5.0 % SVL), outer metatarsal tubercle absent (Fig. 3 F). Dorsal skin relatively smooth; tiny white tubercles scattered on flanks; oval supra-axillary gland raised, located in axillary region dorsally from insertion of forelimb, approximately 0.8 mm in diameter; ventral skin smooth; pectoral gland laterally compressed, 1.0 mm in diameter; oval femoral glands distinct on posteroventral surface of thigh, approximately 0.9 mm in diameter, located on posteroventral surfaces of thighs, closer to knee than to vent; ventrolateral glands, distinctly visible, raised, forming an incomplete line (Fig. 3). Color of the holotype in life. Dorsal surface of body brown, with distinct, black, inverted triangular pattern between the anterior corners of the eyes in connection with a dark brown W-shaped marking in the interorbital region, which is also connected to a W-shaped marking between the axillae; wide dark brown bars in upper lip, with distinct white spots; canthus rostralis reddish; flanks with large irregular black flecks and several small light tangerine tubercles; supratympanic ridge reddish and a large black marking under supratympanic ridge; tympanum bicolored, with the upper 2 / 3 of the tympanum dark brown and the lower 1 / 3 light brown; elbow to upper arm and tibio-tarsal articulation distinctly coppery orange in color on the dorsum; transverse black bars on dorsal surfaces of fingers and toes, lower arms, tarsus, thighs and tibia; iris distinctly bicolored, typically orange in upper half, silver white in lower half, with black reticulations throughout; ventral surface of throat, chest, and belly creamy white; chest and abdomen with distinct dark patches; ventral surface of head and limbs greyish purple; ventral surface of limbs scattered with creamy white spots and small patches; pectoral and femoral glands creamy white, supra-axillary glands light orange (Fig. 3 and Suppl. material 4). Color of holotype in preservative. After three months of storage in 70 % alcohol, the dorsum and limb surfaces fading to uniform light brown, except for upper arm; upper arm surface copper brown; transverse bars on limbs still distinct; ventral surface of limbs, chest, abdomen, and throat greyish white; pectoral, femoral, supra-axillary, and ventrolateral glands greyish white; subarticular tubercles, metacarpal tubercles, and metatarsal tubercle fading to gray (Fig. 4). Distribution and ecology. At present, this species is known to be distributed only in its type locality, that is, the mountains around Shizigou Village, Zhaxi Town, Weixin County, with an altitude of 1280–1400 meters. During the breeding season, it gathers in mountain streams with a width of 1.5–2 meters, surrounded by typical subtropical evergreen broad-leaved forests and bamboo forests (Fig. 5). The stream has a steep slope and low water temperature. There are often waterfalls and pools. The banks are covered with lush plants, mainly grasses. The village can be seen about 1 km away from the stream. Species that inhabit the same environment include Nanorana yunnanensis and Bufo andrewsi. During a field survey in mid-June, male toads were heard chirping in the cracks of huge rocks or under grass leaves beside streams. The chirping sound was like a cricket and varied. When not disturbed, the chirping sound consisted of two syllables, with an interval of about 0.5 seconds between each segment. When stimulated by light or someone passing by, the chirping sound changed to a long single syllable. After the environment stabilized, the chirping sound gradually returned to its former state. If further stimulated, such as by direct light, the toad stopped chirping, shrank into the cracks of the rocks, or crouched until it felt that the surrounding environment was safe. However, no tadpoles were observed during this period, nor were female toads. Comparisons. Phylogenetically, the matrilineal genealogy assigns Leptobrachella weixinensis sp. nov. to L. oshanensis complex (clade A). Thus, we compared Leptobrachella weixinensis sp. nov. to all other recognized species of L. oshanensis complex from clade A, which include L. bijie, L. jinyunensis, L. chishuiensis, L. suiyangensis, L. jinshaensis, L. purpuraventra, L. bourreti, L. dong, L. dushanensis, L. graminicola, L. yeae, L. wulingensis, L. dorsospina, L. yunyangensis, L. niveimontis, L. alpina, L. purpurus, L. eos, L. oshanensis, L. murphyi, L. korifi, L. sinorensis, and L. tengchongensis (e. g., Ohler et al. 2011; Yang et al. 2016, 2018; Wang et al. 2019, 2020; Chen et al. 2020, 2021; Li et al. 2020, 2024; Luo et al. 2020; Cheng et al. 2021; Nguyen et al. 2021; Shi et al. 2021; Luo et al. 2022; Chen et al. 2023; Liu et al. 2023; Matsui et al. 2023; Shi et al. 2023; Suppl. material 3). Leptobrachella weixinensis sp. nov. is significantly different from L. jinyunensis by tibiotarsal articulation reaches the nostril (vs. reaches the level of the middle of the eye), subarticular tubercles distinct under the base of I, II, III and IV toe (vs. absent), dorsal skin relatively smooth (vs. dorsal skin rough with large tubercles in size of humeral glands, without conical spines), iris distinctly bicolored, typically orange in upper half, silver white in lower half (vs. iris gold above, gradually silver bellow), and heels overlapping when thighs are positioned at right angles to the body (vs. heels slightly contact with each other); from L. bijie by interorbital distance wider than internarial distance (vs. internarial distance equal to interorbital distance), tibiotarsal articulation reaches the nostril (vs. reaches the region between middle of eye to anterior corner of eye), heels overlapping when thighs are positioned at right angles to the body