Leptobrachella dorsospina Wang, Lyu, Qi & Wang, 2020

Wang, Jian, Lyu, Zhi-Tong, Qi, Shuo, Zeng, Zhao-Chi, Zhang, Wen-Xiang, Lu, Long-Shan & Wang, Ying-Yong, 2020, Two new Leptobrachella species (Anura, Megophryidae) from the Yunnan-Guizhou Plateau, southwestern China, ZooKeys 995, pp. 97-125 : 97

Leptobrachella dorsospina Wang, Lyu, Qi & Wang sp. nov. Fig. 5

Type material.

Holotype. SYS a004974, adult male, collected by Zhi-Tong Lyu and Run-Lin Li on 21 June 2016 from Yushe Forest Park (26.47°N, 104.80°E; ca. 2100 m a.s.l.), Shuicheng District, Liupanshui City, Guizhou Province, China.

Paratypes (N = 6). An adult male, SYS a004977, and five adult females, SYS a004961/CIB116081, SYS a 004962, SYS a004973, 4975, 4976, collected by Zhi-Tong Lyu and Run-Lin Li on 20-21 June 2016 from the same locality as the holotype.

Diagnosis.

(1) Small size (SVL 28.7-30.5 mm in two adult males, 32.1-39.8 mm in five adult females), (2) dorsal skin rough, with dense conical granules, tubercles, glandular folds and conical spines, (3) iris bicolored, light orange on upper half and silver on lower half, (4) tympanum distinctly discernible, distinct black supratympanic line present, (5) absence of webbing and lateral fringes on fingers, toes with rudimentary webbing and narrow lateral fringes both in males and females, (6) longitudinal ridges under toes interrupted at the articulations, (7) relative finger lengths II = IV <I <III, relative toe length I <II <V <III <IV, (8) heels slightly overlapping, tibia-tarsal articulation reaches forward to the posterior corners of eyes, (9) dorsum greyish brown to dark brown grounding, with distinct darker brown markings and scattered with irregular light greyish brown pigmentations and yellowish brown spots, (10) flanks with several enlarged dark patches positioned longitudinally in two rows, (11) ventral surface greyish white with black spots and orange pigmentations.

Comparison.

Compared with the 26 known congeners of the genus Leptobrachella occurring south of the Kra Isthmus, L. dorsospina sp. nov. can be easily distinguished by the presence of supra-axillary and ventrolateral glands, 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 , all of which are lacking the supra-axillary and ventrolateral glands; and by the significantly larger body size, SVL 28.7-30.5 mm in two adult male, L. dorsospina sp. nov. differs from the smaller L. baluensis (14.9-15.9 mm in males), L. brevicrus (17.1-17.8 mm in males), L. bondangensis (17.8 mm in male), L. fusca (16.3 mm in male), L. itiokai (15.2-16.7 mm in males), L. juliandringi (17.0-17.2 mm in males), L. mjobergi (15.7-19.0 mm in males), L. natunae (17.6 mm in one adult male), L. parva (15.0-16.9 mm in males), L. palmata (14.4-16.8 mm in males), and L. serasanae (16.9 mm in female).

Leptobrachella dorsospina sp. nov. can be easily distinguished from Leptobrachella aspera sp. nov. by having distinctly larger body size, SVL 28.7-30.5 mm in males, 32.1-39.8 mm in females (vs. SVL 22.4 mm in male, 25.0-26.4 in females); conical spines on dorsal skin present (vs. absent); black spots on flanks in one row (vs. black spots on flanks in two rows); ventral skin greyish white with black spots and orange pigmentations (vs. ventral skin creamy white with distinct dark patches on chest and abdomen); longitudinal ridges under toes interrupted at the articulations (longitudinal ridges under toes not interrupted at the articulations).

For the remaining 56 members of the genus Leptobrachella , in having SVL 28.7-30.5 mm in two males, L. dorsospina sp. nov. differs from the larger L. eos (33.1-34.7 mm in males), L. nahangensis (40.8 mm in male), L. sungi (48.3-52.7 mm in males), L. tamdil (32.3 mm in male), and L. zhangyapingi (45.8-52.5 mm in males); and from the smaller L. alpina (24.0-26.4 mm in males), L. applebyi (19.6-22.3 mm in males), L. ardens (21.3-24.7 mm in males), L. bidoupensis (18.5-25.4 mm in males), L. crocea (22.2-27.3 mm in males), L. feii (21.5-22.8 mm in males), L. flaviglandulosa (23.0-27.0 mm in males), L. isos (23.7-27.9 mm in males), L. khasiorum (24.5-27.3 mm in males), L. laui (24.8-26.7 mm in males), L. maculosa (24.2-26.6 mm in males), L. mangshanensis (22.2-27.8 mm in males), L. melica (19.5-22.7 mm in males), L. niveimontis (22.5-23.6 mm in males), L. pallida (24.5-27.7 mm in males), L. petrops (23.6-27.6 mm in males), L. pluvialis (21.3-22.3 mm in males), L. puhoatensis (24.2-28.1 mm in males), L. purpura (25.0-27.5 mm in males), L. rowleyae (23.4-25.4 mm in males), L. tadungensis (23.3-28.2 mm in males), L. tengchongensis (23.9-26.0 mm in males), L. ventripunctata (25.5-28.0 mm in males), and L. yingjiangensis (25.7-27.6 mm in males). By having black spots on the flanks, L. dorsospina sp. nov. can be distinguished from L. aerea , L. botsfordi , L. firthi , and L. tuberosa , all of which lack black spots on the flanks. By having rough dorsal skin with conical spines, the new species can be distinguished from L. bijie , L. chishuiensis , L. liui , L. maoershanensis , L. pyrrhops , L. purpuraventra , L. suiyangensis , L. wuhuangmontis , L. wulingensis , and L. yunkaiensis (dorsal skin lacking spines); and from L. bourreti , L. fuliginosa , L. kalonensis , L. minima , L. oshanensis , and L. pelodytoides (dorsal skin smooth). By having narrow lateral fringes on the toes, the new species can be distinguished from L. lateralis , L. macrops , L. nyx , L. pyrrhops , L. namdongensis and L. neangi , all of which lack lateral fringes on the toes. The new species can be separated from the remaining L. nokrekensis by having greyish white ventral coloration with black patches and orange pigmentations (vs. creamy white), and having dense short glandular folds on the dorsal surface (vs. only a few glandular folds on the dorsal surface).

Description of holotype.

Adult male. Body size rather small, SVL 30.5 mm. Head length slightly larger than head width, HDW/HDL 0.99; snout slightly protruding, projecting slightly beyond margin of the lower jaw; nostril closer to snout than eye; canthus rostralis gently rounded; loreal region slightly concave; interorbital space flat, internarial distance smaller than interorbital distance, IND/IOD 0.91; pineal ocellus absent; vertical pupil; snout length larger than eye diameter, SNT/EYE 1.29; tympanum distinct, rounded, and slightly concave, diameter smaller than that of the eye and larger than tympanum-eye distance, TMP/EYE 0.43 and TEY/TMP 0.50; upper margin of tympanum in contact with supratympanic ridge; distinct black supratympanic line present; vomerine teeth absent; vocal sac openings slit-like, paired, located posterolaterally on floor of mouth in close proximity to the margins of the mandible; tongue deeply notched posteriorly; supratympanic ridge distinct, extending from posterior corner of eye to supra-axillary gland.

Tips of fingers rounded, slightly swollen; relative finger lengths II = IV <I <III; nuptial pad absent; subarticular tubercles absent; large, rounded inner palmar tubercle distinctly separated from small, rounded outer palmar tubercle; absence of webbing and lateral fringes on fingers. Tips of toes rounded, slightly swollen; relative toe length I <II <V <III <IV; subarticular tubercles absent; distinct longitudinal dermal ridges present under the 3rd to 5th toes, interrupted; large, oval inner metatarsal tubercle present, outer metatarsal tubercle absent; toes webbing rudimentary; narrow lateral fringes present on all toes. Tibia 44% of snout-vent length; tibiotarsal articulation reaches to posterior corner of eye; heels slightly overlapping when thighs are appressed at right angles with respect to body.

Dorsal skin rough, with dense conical granules, tubercles, glandular folds and conical spines; ventral skin smooth; pectoral gland and femoral gland oval; the size of pectoral glands almost equal to tips of fingers and femoral glands; femoral gland situated on posteroventral surface of thigh, closer to knee than to vent; supra-axillary glands raised. Ventrolateral glands distinctly visible, raised, forming an incomplete line.

Coloration of holotype in life.

Dorsum greyish brown with distinct darker brown markings on sides and scattered with irregular light greyish brown pigmentations and yellowish brown spots. An indistinct, darker brown inverted triangular pattern between anterior corners of the eyes, connected to an indistinct dark brown W-shaped marking between the axillae. Dense translucent spines present on dorsal skin of body and limbs. Upper 2/3 of the tympanum dark brown, lower 1/3 light orange, scattered with tiny coppery orange spots. Small greyish white and light brown granules present on the dorsum of the body and limbs; a dark brown vertical bar under the eye; transverse dark brown bars on the dorsal surface of the limbs and digits; distinct dark brown patches on the flanks, from groin to axilla; elbow and upper arms with distinct light orange coloration.

Ventral surface of throat, chest, and belly greyish white; throat with light brown speckles, chest, and abdomen with distinct dark patches; ventral surface of limbs dark grey, scattered with greyish white spots and small patches. Supra-axillary gland light orange; femoral, pectoral, and ventrolateral glands greyish white. Iris bicolored, light orange on upper half and silver on lower half.

Coloration of holotype in preservative

(Fig. 4B ). Dorsum of body and limbs dark brown; transverse bars on limbs, dark brown patterns, markings, and spots on back become indistinct, light greyish brown pigmentations and yellowish spots absent. Translucent spines on dorsal skin of body and limbs become grey. Ventral surface of limbs and surface of throat light brown, surface of abdomen greyish white, dark patches on chest, abdomen and flanks become more distinct. Supra-axillary, femoral, pectoral, and ventrolateral glands greyish white.

Variations.

Measurements and body proportions are listed in Table 5 . All the female paratypes match the overall characters of the holotype except that: the dorsum is greyish brown in the holotype SYS a004974 (vs. dark brown in the paratypes SYS a004961, 4962), and black spots on the ventral skin are more dense and distinct in the paratypes SYS a004961, 4962.

Etymology.

The specific epithet, dorsospina , is in reference to the conical spines on the dorsal surface of body in the new species. According to its type locality, we suggest its English common name as "Shuicheng Leaf Litter Toad", and the Chinese name "Shui Cheng Zhang Tu Chan ( 水城掌突蟾)”.

Distribution and habits.

Currently, Leptobrachella dorsospina sp. nov. is known only from its type locality, Yushe Forest Park, which is near the border between Guizhou and Yunnan. The new species was found on the surface of fallen leaves by the clear-water rocky hill-stream in well-preserved montane evergreen broadleaf forest (ca. 2100 m a.s.l.). Males were not heard calling.

Figures

Figure 4. Morphological features in preserved specimens of A Leptobrachella aspera sp. nov., holotype SYS a 007743 B Leptobrachella dorsospina sp. nov., holotype SYS a 004974. Ellipse selected region showing the tiny spines on dorsal skin.

Figure 5. Morphological features in life. Leptobrachella dorsospina sp. nov., holotype SYS a 004974.