Leptobrachella xishuiensis Luo, Deng & Zhou, 2025

Leptobrachella xishuiensis Luo, Deng & Zhou sp. nov.

Table 2 View Table 2 ; Suppl. material 7; Figs 6 View Figure 6 , 7 View Figure 7

Material examined.

Holotype. • GZNU 20240726001 , adult male collected by Tao Luo on 26 July 2018 from the Xianyuan Town , Xishui County, Guizhou, China (28.30094224 ° N, 106.71286583 ° E, 1601 m a. s. l.; Fig. 1 View Figure 1 ). GoogleMaps

Paratypes. • GZNU 20240726002–006 , four adult males were collected from the type locality on 6 June 2018, by Tao Luo, Zi-Fa Zhao, Chang-Ting Lan, and Zhong-Lian Wang .

Etymology.

The specific epithet “ xishuiensis ” refers to the name of the type locality, Xishui County, Guizhou, China. We suggest the English name “ Xishui Leaf-litter Toad ” and the Chinese name “ Xí Shuǐ Zhǎng Tū Chán (习水掌突蟾) ”.

Diagnosis.

Leptobrachella xishuiensis sp. nov. can be distinguished from its congeners by a combination of the following characters: (1) SVL 28.1–36.2 mm in males; (2) toes rudimentary webbed, lateral fringes on toes absent; (3) dorsal surface shagreened with small, raised tubercles and longitudinal ridges; (4) ventral surface greyish-white without dark brown spots; (5) throat, chest and ventral surfaces of limbs purplish-grey; (6) iris bicoloured, upper 1 / 3 copper, transitioning to silver in lower 2 / 3; (7) distinct black spots present on flanks; and (8) prominent inner palmar tubercle separated from the small outer palmar tubercle; (9) tibia-tarsal articulation reaching the tip of snout.

Description of the holotype.

Adult male, body size moderate, SVL 36.2 mm. Head length slightly wider than head width; snout short, rounded, protruding, projecting over the lower jaw, longer than eye diameter; nostril oval, closer to the tip of snout than eye; canthus rostralis distinct; loreal region sloping and slightly concave; interorbital region flat, slightly longer than internarial distance; pupil vertical; eyes large, diameter near equal to snout length (EYE / SNT = 0.9); tympanum distinct, rounded and slightly concave and its diameter conspicuously less than eye diameter (TD / EYE = 0.6); supra-tympanic fold distinct, raised from corner of eye to supra-axillary gland; vocal sac openings located laterally on the floor of mouth; tongue cordiform, shallow notch at the posterior tip.

Fore-limbs slender and short, length of lower arm and hand 45.1 % of SVL; tips of fingers rounded and slightly swollen; relative finger lengths I <II <IV <III; nuptial pad absent; subarticular tubercles absent; prominent inner palmar tubercle, separated from the small outer palmar tubercle; finger webbing and dermal fringes absent. Hind-limbs slender, tibia slightly nearly equal to thigh length (THL / TIB = 0.9); TIB / SVL = 0.5; tips of toes rounded, slightly swollen; relative toe length I <II <V <III <IV; subarticular tubercles absent, replaced by distinct dermal ridges; pronounced large, oval inner metatarsal tubercle; outer metatarsal tubercle absent; 1 / 3 toe webbing; lateral fringes absent; tibia-tarsal articulation reaching the tip of snout; heels overlapping when thighs are appressed at right angles to body.

Dorsal surface shagreened with small, raised tubercles and longitudinal ridges; ventral and chest skin smooth without tubercles; anterior throat with several tubercles; pectoral glands oval; femoral glands oval, located on the posteroventral surface of thighs, closer to the knee than to the vent; supra-axillary glands distinct and rounded; a pair of glands under the vent; and ventrolateral glands distinctly visible and raised, forming an incomplete line.

Colour of the holotype in life.

Dorsal surface greyish-brown, an inverted triangle marking between eyes, irregular markings on shoulder and rear of the back; flanks with greyish-white tubercles and irregular black spots; tympanum bicoloured, with the upper half of the tympanum pale brown and the lower half light greyish-brown; supratympanic line black from posterior corner of the eye to supra-axillary glands; light brown between the posterior corner of the eyes and the tympanum; wide brown bars on the upper lip; brown transverse bars distinct on dorsal surface of fore-limbs and hind-limbs; upper arm surfaces light orange; ventral surface greyish-white without dark brown spots; throat immaculate purplish-grae and its margin concentrated white tubercles; chest purplish-grey; ventral surfaces of limbs purplish-grey, scattered with white tubercles; pectoral and femoral glands and a pair of creamy-white glands under the vent, supra-axillary glands white; pupil black; iris bicoloured, upper one-third copper, transitioning to silver in lower two-thirds (Fig. 7 A 4 View Figure 7 ).

Colour of the holotype in preservation.

In a 10 % formalin preservation solution, dorsum and limb surfaces faded to a uniform dark brown; brown, inverted triangle markings distinctly visible between the eyes; irregular black spots distinct on flanks; dorsolateral markings and longitudinal skin ridges and spots on dorsal becoming more distinct; throat, chest and belly creamy-white; pectoral, femoral, supra-axillary and ventrolateral glands creamy-white; dark transverse bars on limbs, fingers and toes remained distinct; upper arm and tibiotarsus faded to greyish-white.

Variation.

Measurements of the type series are shown in Suppl. material 7. All of the male paratypes matched the overall characters of the holotype. The black spots and tubercles on the flanks exhibited variation between individuals. Certain individuals possess lesser tubercles and continued longitudinal ridges on their dorsum and hind-limb surfaces (Fig. 7 C 1 View Figure 7 ), while others exhibit a light brown colouration on their dorsum (Fig. 7 C 1 View Figure 7 ).

Ecology and distribution.

Leptobrachella xishuiensis sp. nov. was found only in bamboo forests at 1600 m elev. All of the individuals were inhabiting bamboo leaves about 1.2 m from the stream and did not call. Juveniles that came ashore were also found during the survey. Based on this, the breeding season may be around May to June. Frogs discovered in the area included Megophrys qianbeiensis and Quasipaa boulengeri .

Comparisons.

Suppl. material 9 presents a concise overview of the diagnostic morphological characters of species found north of the Isthmus of Kra. From the 26 congeners of the genus Leptobrachella occurring south of the Kra Isthmus, by the presence of supra-axillary and ventrolateral glands, new species can easily be distinguished from L. arayai , L. dringi , L. fritinniens , L. gracilis , L. hamidi , L. heteropus , L. kajangensis , L. kecil , L. marmorata , L. melanoleuca , L. maura , L. picta , L. platycephala , L. sabahmontana , and L. sola (vs. absent in the latter); by having a moderate body size (SVL 28.1–36.2 mm in males), the new species differs from L. baluensis , L. brevicrus , L. bondangens is, L. fusca , L. itiokai , L. juliandringi , L. mjobergi , L. natunae , L. parva , L. palmata , and L. serasanae (vs. less than 18 mm in the latter males or females).

By the moderate body size of the male (SVL 28.1–36.2 mm), the new species differs from the smaller males L. alpina , L. applebyi , L. ardens , L. aspera , L. bashaensis , L. bidoupensis , L. crocea , L. feii , L. flaviglandulosa , L. graminicola , L. khasiorum , L. laui , L. maculosa , L. mangshanensis , L. melica , L. murphyi , L. pallida , L. petrops , L. tengchongensis , L. verrucosa , L. wumingensis , and L. yingjiangensis (vs. <28 mm in the latter); and from the larger L. nahangensis , L. sungi , and L. zhangyapingi (vs. larger than 40 mm in the latter).

By the presence of black spots on flanks, the new species differs from L. aerea , L. botsfordi , L. eos , L. firthi , L. isos , and L. tuberosa (vs. absent). From the rudimentary webbing on the toes, the new species differs from L. jinshaensis , L. jinshaensis , L. kalonensis , L. oshanensis , L. rowleyae , L. shiwandashanensis , and L. tadungensis (vs. absent); from L. pelodytoides and L. tamdil (vs. wide); and from L. guinanensis (vs. 1 / 3 toe webbing). By the absence of lateral fringes on toes, the new species differs from L. bijie , L. bourreti , L. chishuiensis , L. damingshanensis , L. dong , L. dorsospina , L. dushanensis , L. fuliginosa , L. jinyunensis , L. korifi , L. liui , L. maoershanensis , L. niveimontis , L. phiadenensis , L. phiaoacensis , L. puhoatensis , L. purpurus , L. purpuraventra , L. shangsiensis , L. shimentaina , L. sinorensis , L. wuhuangmontis , L. wulingensis , L. yeae , L. yunkaiensis , and L. yunyangensis (vs. present in the latter).

By the tibia-tarsal articulation reaching the tip of the snout when the leg is stretched forward, the new species differs from L. macrops (vs. reaching the eye), L. neangi (vs. reaching just past the anterior edge of the eye), L. nokrekensis (vs. reaching the posterior corner of eye), L. pluvialis (vs. reaching the nostril), and L. ventripunctata (vs. reaching between the eye and the tympanum). By having dorsal surface shagreened with small, raised tubercles and longitudinal ridges, ventral surface greyish-white without dark brown spots and throat and chest purplish-grey, the new species differs from L. lateralis (vs. dorsum with roughly granular and belly creamy-white), L. minima (vs. dorsum smooth and ventral surface creamy-white), L. namdongensis (vs. dorsum with finely tuberculate and belly creamy-white with brown dusting on the margins), L. nyx (vs. dorsum with rounded tubercles and belly creamy-white with brown margins), L. pingbianensis (vs. dorsum smooth and chest and belly with dark brown spots), and L. pyrrhops (vs. dorsum slightly shagreened and belly reddish-brown with white speckling).

The new species can clearly be distinguished from its phylogenetically close congener L. suiyangensis . L. xishuiensis sp. nov. differs from L. suiyangensis as follows: lateral fringes on the toes absent (vs. present), dorsal surface shagreened with small, raised tubercles and longitudinal ridges (vs. dorsum slightly smooth, with light reddish-brown tubercles), ventral surface greyish-white without dark brown spots (vs. yellowish creamy-white with marble texture chest and belly or with irregular light brown speckling), throat and chest purplish-grey (vs. throat is grey-white and chest yellowish-creamy-white), tibia-tarsal articulation reaches the tip of snout (vs. reaching the anterior eye), prominent inner palmar tubercle, separated from the small outer palmar tubercle (vs. palmar tubercle not distinct), and iris bicoloured, upper one-third copper, transitioning to silver in lower two-thirds (vs. coppery-orange on the upper half and silver grey on the lower half) (Fig. 7 A 4, B 4, C 4 View Figure 7 ). For morphs EYE, IOD, HND, LW and HLL, the new species is significantly larger than L. suiyangensis (Table 2 View Table 2 ) and can be distinguished on the PC 1 axis (Fig. 5 View Figure 5 ; Suppl. material 14).