Leptobrachella aspera 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 aspera Wang, Lyu, Qi & Wang sp. nov. Fig. 3

Type material.

Holotype. SYS a007743, adult male, collected by Jian Wang, Yao Li and Yu-Long Li on 31 May 2019 from Huanglianshan Nature Reserve (22.89°N, 102.29°E; ca. 1930 m a.s.l.), Lyuchun County, Yunnan Province, China.

Paratypes (N = 3). Three adult females, SYS a007744-7745, SYS a007746/CIB116080, the same collection data as the holotype.

Diagnosis.

(1) Small size (SVL 22.4 mm in a single adult male, 25.0-26.4 in three adult females), (2) dorsal skin rough, with dense conical granules, tubercles and glandular folds, (3) iris bicolored, amber 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 not interrupted at the articulations, (7) relative finger lengths I <IV <II <III, relative toe length I <II <V <III <IV, (8) heels just meeting, tibia-tarsal articulation reaches the region between middle of eye to anterior corner of eye, (9) dorsum greyish brown to yellowish brown grounding, with small light orange granules and distinct darker brown markings scattered with irregular light orange or greyish white pigmentations, (10) flanks with several enlarged dark patches with light yellowish green margin, (11) ventral surface creamy white, with distinct regular dark patches on chest and abdomen.

Comparison.

From the 26 known congeners of the genus Leptobrachella occurring south of the Kra Isthmus, the presence of supra-axillary and ventrolateral glands, can easily distinguish L. aspera sp. nov. 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 lack the supra-axillary and ventrolateral glands; and by the significantly larger body size, SVL 22.4 mm in a single male, L. aspera 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 aspera sp. nov. is recovered as a sister taxon to L. feii in the phylogenetic tree (Fig. 2 ). However, the new species can be distinguished from L. feii by the following morphological characters: head relatively short, HDL/SVL 0.33-0.35 (vs. head relatively long, HDL/SVL 0.38-0.43); distinct regular dark patches on skin of chest and abdomen (vs. irregular black blotches scattered on skin of chest and belly); color of upper half of iris amber (vs. color of upper half of iris lighter, golden orange); ventrolateral glands forming an non-continuous line (vs. ventrolateral glands forming a continuous line); relative finger lengths I <IV <II <III (vs. relative finger lengths II <I <IV <III); tibio-tarsal articulation of adpressed limb reaching the region between middle of eye to anterior corner of eye (vs. tibio-tarsal articulation of adpressed limb reaching beyond eye).

While Leptobrachella pluvialis is distributed in the same mountain range on the Vietnamese side and possesses similar body size ( Ohler et al. 2000), it can be separated from L. aspera sp. nov. by the following characters: (1) smooth dorsal skin with flattened tubercles on flanks (vs. rough dorsal skin with dense conical granules in L. aspera sp. nov.), (2) absence of webbing on toes (vs. rudimentary webbing on toes in L. aspera sp. nov.), and (3) relatively longer hindlimbs, the tibia-tarsal articulation reaching to the nostril (vs. relatively shorter hindlimbs, the tibia-tarsal articulation reaching the region between middle of eye to anterior corner of eye in L. aspera sp. nov.).

For the remaining 54 members of the genus Leptobrachella , in having SVL 22.4 mm in a single male, L. aspera sp. nov. differs from the larger L. aerea (25.1-28.9 in males), L. alpina (24.0-28.9 mm in males), L. bijie (29.0-30.4 mm in males), L. botsfordi (29.1-32.6 mm in males), L. bourreti (28.0-36.2 mm in males), L. chishuiensis (30.8-33.4 in males), L. eos (33.1-34.7 mm in males), L. firthi (26.4-29.2 mm in males), L. flaviglandulosa (23.0-27.0 mm in males), L. fuliginosa (28.2-30.0 mm in males), L. isos (23.7-27.9 mm in males), L. kalonensis (25.8-30.6 mm in males), L. khasiorum (24.5-27.3 mm in males), L. laui (24.8-26.7 mm in males), L. lateralis (26.9-28.3 mm in males), L. macrops (28.0-29.3 mm in males), L. maculosa (24.2-26.6 mm in males), L. minima (25.7-31.4 mm in males), L. nahangensis (40.8 mm in male), L. nokrekensis (26.0-33.0 mm in males), L. nyx (26.7-32.6 mm in males), L. neangi (30.9 mm in male), L. namdongensis (30.9 mm in male), L. oshanensis (26.6-30.7 mm in males), L. pallida (24.5-27.7 mm in males), L. pelodytoides (27.5-32.3 mm in males), L. petrops (23.6-27.6 mm in males), L. puhoatensis (24.2-28.1 mm in males), L. purpura (25.0-27.5 mm in males), L. purpuraventra (27.3-29.8 mm in males), L. pyrrhops (30.8-34.3 mm in males), L. rowleyae (23.4-25.4 mm in males), L. suiyangensis (28.7-29.7 mm in males), L. sungi (48.3-52.7 mm in males), L. tadungensis (23.3-28.2 mm in males), L. tamdil (32.3 mm in male), L. tengchongensis (23.9-26.0 mm in males), L. tuberosa (24.4-29.5 mm in males), L. ventripunctata (25.5-28.0 mm in males), L. wuhuangmontis (25.6-30.0 mm in males), L. yingjiangensis (25.7-27.6 mm in males), L. yunkaiensis (25.9-29.3 mm in males), and L. zhangyapingi (45.8-52.5 mm in males). By presence of black spots on flanks, the new species can be distinguished from L. crocea , versus absence of black spots on flanks; by rudimentary webbing on toes, the new species can be distinguished from L. ardens , versus absence of webbing on toes; by narrow lateral fringes on toes, the new species can be distinguished from L. applebyi , L. ardens , L. crocea , and L. melica , all having no lateral fringes on toes, and from L. liui , having wide lateral fringes on toes; by the creamy white ventral coloration and distinct regular dark patches on the chest and abdomen, the new species can be distinguished from L. applebyi , L. ardens , L. bidoupensis , and L. melica , all having reddish brown ventral coloration with white specks, from L. crocea , having bright orange ventral coloration, from L. mangshanensis , lacking dark skin patches on the chest and abdomen, from L. liui , having creamy white ventral coloration with dark brown spots on the chest and margins, and from L. niveimontis , having marbling ventral coloration with black speckling; by rough dorsal skin with dense conical granules, tubercles and glandular folds, the new species can be distinguished from L. applebyi , L. ardens , L. bidoupensis , L. mangshanensis , L. melica , and L. niveimontis , all having smooth dorsal skin.

Description of holotype.

Adult male. Body size small, SVL 22.4 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 greater than interorbital distance, IND/IOD 1.07; pineal ocellus absent; pupil vertical; snout length longer than eye diameter, SNT/EYE 1.26; tympanum distinct, rounded, and slightly concave, diameter smaller than that of the eye and larger than tympanum-eye distance, TMP/EYE 0.52 and TEY/TMP 0.44; 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 I <IV <II <III; nuptial pad absent; subarticular tubercles absent; large, rounded inner palmar tubercle distinctly separated from small, rounded outer palmar tubercle; webbing and lateral fringes on fingers absent. 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, not interrupted; large, oval inner metatarsal tubercle present, outer metatarsal tubercle absent; toes webbing rudimentary; narrow lateral fringes present on all toes. Tibia 47% of snout-vent length; tibiotarsal articulation reaching to anterior 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 and glandular folds; ventral skin smooth; sparse tiny tubercles present on surface of chest; 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 small light orange granules, distinct darker brown markings scattered with irregular light orange and greyish white pigmentations. A dark brown 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. Tympanum dark brown. Small light orange granules present on dorsum of body and limbs; a dark brown blotch under the eye; transverse dark brown bars present on dorsal surface of limbs and digits; distinct dark brown patches with light yellowish green margin on flanks from groin to axilla; elbow and upper arms with distinct coppery orange coloration.

Ventral surface of throat, chest, and belly creamy white; presence of distinct nebulous greyish speckles present on throat, and distinct dark patches on chest and abdomen; ventral surface of limbs greyish purple, scattered with greyish white spots and small patches. Supra-axillary gland coppery orange; femoral, pectoral, and ventrolateral glands greyish white. Iris bicolored, amber on upper half and silver on lower half.

Coloration of holotype in preservative

(Fig. 4A ). Dorsum of body and limbs dark brown; transverse bars on limbs become more distinct; dark brown patterns, markings and spots on the back become indistinct, orange pigmentations become dark brown, greyish white pigmentations become dark grey. Ventral surface of limbs and surface of throat light brown, surface of abdomen greyish white, nebulous speckles on throat absent, dark patches on chest, abdomen and flanks become more distinct, light yellowish green margin of patches on flanks absent. Supra-axillary, femoral, pectoral, and ventrolateral glands greyish white.

Variation.

Measurements and body proportions are listed in Table 4 . Nonsexual characters of all the female paratypes (SYS a007744, 7745, 7746) match the overall characters of the holotype except that: the dorsum is greyish brown in the holotype SYS a007743 (vs. yellowish brown in the paratypes); the size of the pectoral glands are almost equal to the tips of the fingers and the femoral glands (vs. the size of the pectoral glands are larger than the tips of fingers and the femoral glands in the paratypes); the tibia-tarsal articulation reaches forward to the anterior corner of the eye in the holotype (vs. the tibia-tarsal articulation reaches forward to the middle of the eye in the paratypes SYS a007745, 7746); the ventral skin of the thighs smooth (vs. the ventral skin of the thighs rough with dense raised tubercles in the paratypes).

Etymology.

The specific epithet, aspera , is a Latin adjective which means rough, in reference to the dorsal skin texture of the new species. According to its type locality, we suggest its English common name as "Huanglianshan Leaf Litter Toad", and the Chinese name "Huang Lian Shan Zhang Tu Chan ( 黄连山掌突蟾)”.

Distribution and habits.

Currently, Leptobrachella aspera sp. nov. is known only from its type locality Huanglianshan Nature Reserve, near the border between China and Vietnam. The new species was found along a drainage ditch of a mountainous road. The road was surrounded by broad-leaved forest at an altitude ca. 1930 m and not close to any hillstreams. Males were not heard calling during the field survey from 31 May to 1 June 2019.

Figures

Figure 2. Bayesian Inference tree. The Bayesian posterior probabilities (BPP)> 0.90 were retained.

Figure 3. Morphological features in life. Leptobrachella aspera sp. nov., holotype SYS a 007743.

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.