Leptobrachella verrucosa Wang, Zeng, Lin & Li, 2022

Lin, Shi-Shi, Li, Yuan-Hang, Lu, Yu-Hong, Su, Hong-Lin, Wu, Shi-Bin, Zhang, Qi-Qi, Mo, Mei-Juan, Xiao, Shao-Jun, Pan, Zhong, Pan, Hu-Jun, Zeng, Zhao-Chi & Wang, Jian, 2022, A new species of the genus Leptobrachella (Anura, Megophryidae) from northwestern Guangdong Province, China, Herpetozoa 35, pp. 165-178 : 165

Leptobrachella verrucosa Wang, Zeng, Lin & Li sp. nov.

Figs 3 , 4 Verrucous Leaf Litter Toad (in English) / Mi You Zhang Tu Chan (密疣掌突蟾 in Chinese)

Type material.

Holotype ♂. GEP a062, collected by Shi-Shi Lin and Qi-Qi Zhang on 31 May 2022 from Lianshan Bijiashan Nature Reserve (24°12'49.63"N, 111°59'39.31"E; ca. 550 m a.s.l.), Lianshan County, Qingyuan City, Guangdong Province, China.

Paratypes. 4 ♂: GEP a059-061, 063, the same collection data as the holotype.

Etymology.

The specific epithet " Leptobrachella verrucosa " is an adjective meaning “verrucous”, referring to the tuberculate dorsal skin texture of the new species.

Diagnosis.

(1) Small body size [SVL 23.2-25.9 mm in five adult males], (2) iris bicolored, upper half coppery orange and lower half grayish brown, (3) tympanum distinct, (4) supratympanic line black, (5) fingers without lateral fringes, (6) toes with rudimentary webbing, lateral fringes narrow, (7) longitudinal ridges under toes continuous, (8) heels not meeting when adpressed, tibial-tarsal articulation reaching anterior corner of eye, (9) dorsal surface shagreened with numerous conical tubercles, lacking spines, enlarged warts or skin ridges, (10) ventral surface smooth, (11) dorsum grayish brown, with distinct darker brown scattered markings and irregular light orange pigmentations, (12) flanks with several dark spots, (13) ventral surface creamy white with grayish white and dark brown spots.

Description of holotype.

Adult male. Body size small, SVL 23.2 mm. Head length slightly larger than head width, HDW/HDL 0.95; snout slightly protruding, projecting slightly beyond margin of lower jaw; nostril closer to snout than eye; canthus rostralis gently rounded; loreal region slightly concave; interorbital space flat, internarial distance slightly larger than interorbital distance, IND/IOD 1.05; pineal ocellus absent; pupil vertical; snout slightly longer than eye diameter, SNT/EYE 1.03; tympanum distinct, rounded, diameter smaller than that of eye and larger than tympanum-eye distance, TMP/EYE 0.54, TEY/TMP 0.46; upper margin of tympanum in contact with supratympanic ridge; vomerine teeth absent; a single vocal sac; vocal sac openings slit-like, paired, located posterolaterally on floor of mouth, close to margins of mandible; tongue deeply notched distally; supratympanic ridge distinct, extending from posterior corner of eye to supra-axillary gland.

Tips of fingers rounded, slightly swollen; relative finger lengths I = II = IV <III; nuptial pad absent; subarticular tubercles absent; inner palmar tubercle large, rounded, distinctly separated from outer palmar tubercle; outer palmar tubercle small, rounded; fingers lacking interdigital webbing and lateral fringes. Tips of toes rounded, slightly swollen; relative toe length I <II <V <III <IV; longitudinal ridges under toes continuous; inner metatarsal tubercle large, oval; outer metatarsal tubercle absent; interdigital webbing between toes rudimentary; narrow lateral fringes present on all toes. Tibia 49% of snout-vent length; tibiotarsal articulation reaches to anterior corner of eye; heels not meeting when thighs are appressed at right angles with respect to the body.

Dorsal surface shagreened with numerous conical tubercles, lacking spines, enlarged warts or skin ridges; ventral skin smooth; pectoral and femoral glands oval; both larger in diameter than tip of fingers; femoral glands larger in diameter than tip of toes; femoral gland situated on posteroventral surface of thigh, closer to knee than to vent; supra-axillary gland raised. Ventrolateral gland distinctly visible, forming a longitudinal uncontinuous series.

Coloration of holotype in life.

Dorsal background color grayish brown, with distinct dark brown markings, and rounded spots, and scattered with irregular light orange pigmentation. A dark brown inverted triangular marking in interorbital region, connecting to dark brown W-shaped marking on occipital region. Tympanum dark brown, lower margin grayish white. Supratympanic line black. A pair of dark brown vertical bars present under eyes; transverse dark brown bars on dorsal surfaces of distal limbs and digits; distinct dark brown blotches on flanks; surfaces of elbows and upper arms coppery orange, with dark markings and spots.

Surface of throat, chest, belly and underside of forelimbs creamy white, with distinct grayish white and dark brown spots; under side of hindlimbs grayish purple with numerous white spots. Supra-axillary gland coppery orange, pectoral glands grayish white, femoral glands coppery orange, anterior half of ventrolateral glands coppery and posterior half grayish white. Iris bicolored, upper half coppery orange, lower half grayish brown.

Coloration of holotype in preservative.

Dorsal background color dark brown scattered with irregular gray pigmentations. All markings, bars and spots become indistinct. Tympanum dark brown.

Ventral surface grayish white; grayish white spots absent, dark brown spots become more distinct. Supra-axillary, pectoral, and ventrolateral glands greyish white.

Variation.

Measurements and body proportions are listed in Table 2 . The paratypes, GEP a059 (Fig. 4A ), GEP a060 (Fig. 4B ), and GEP a063 (Fig. 4D ), show lighter coloration of markings and pigmentations on dorsum. The paratype, GEP a061 (Fig. 4C ), possesses a more tuberculate dorsal skin texture. Pectoral glands much more distinct in all paratypes.

Distribution, ecology and conservation.

Leptobrachella verrucosa sp. nov. is currently only known from its type locality (Fig. 1 ; ca. 500-600 m a.s.l.) which is located at the boundary of Guangxi Zhuang Autonomous Region, and Guangdong and Hunan provinces. The new species inhabits clear-water rocky streams in primary forests surrounded by broad-leaved forest in granite landforms. Males were observed calling while perched on rocks or leaves of dwarf shrubs near flowing seeps. Data of larvae and females remain unknown. The breeding season lasts from April to June according to our long-term observation. We recommend the new species be listed as LC (Least Concerned) in the IUCN categorization as the forest is well protected and the distribution of the species is potentially wider than currently known, i.e. the adjacent Hunan Province and Guangxi Zhuang Autonomous Region.

Comparisons.

In the phylogenetic tree (Fig. 2 ), Leptobrachella verrucosa sp. nov. is most closely related to the clade composed of L. liui and L. mangshanensis , therefore, the latter two are selected for detailed comparison (Table 3 ). The new species differs from L. liui by its narrow fringes along lateral surfaces of toes (vs. wide), continuous longitudinal ridges under toes (vs. interrupted), dorsal surface with numerous conical tubercles and lacking skin ridges (vs. dorsal surface with rounded warts and sparse short skin ridges), heels not meeting when adpressed (vs. heels meeting). The new species differs from L. mangshanensis by its shagreened dorsal surface with numerous conical tubercles, lacking spines, enlarged warts or skin ridges (vs. dorsal surface almost smooth with tiny transparent spines, small tubercles and sparse short skin ridges), ventral surface of thighs lacking conical spines (vs. ventral surface bearing conical spines), tibial-tarsal articulation reaching anterior corner of eye (vs. reaching tip of snout, well beyond anterior corner of eye).

Leptobrachella verrucosa sp. nov. can be distinguished from L. yunkaiensis and L. shimentaina by having no fringes along lateral surfaces of fingers (vs. lateral fringes present in L. yunkaiensis and males of L. shimentaina ); narrow fringes along lateral surfaces of toes (vs. lateral fringes wide in L. yunkaiensis and males of L. shimentaina ); shagreened dorsal surface with numerous conical tubercles, lacking spines, enlarged warts or skin ridges (vs. dorsal surface with skin ridges in L. shimentaina , dorsal surface with short skin ridges and raised warts in L. yunkaiensis ); heels not meeting when adpressed (vs. heels slightly overlapping in L. shimentaina , heels meeting in L. yunkaiensis ). Leptobrachella verrucosa sp. nov. can be distinguished from L. bashaensis and L. maoershanensis by having shagreened dorsal surface with numerous conical tubercles, lacking spines, enlarged warts or skin ridges (vs. dorsum shagreened with small tubercles in L. bashaensis , dorsum with skin ridges in L. maoershanensis ); tibial-tarsal articulation reaching anterior corner of eye (vs. reaching tip of snout, well beyond anterior corner of eye in L. bashaensis and L. maoershanensis ). Leptobrachella verrucosa sp. nov. can be distinguished from L. laui by having no lateral fringes along lateral surfaces of fingers (vs. moderate lateral fringes present), narrow lateral fringes along lateral surfaces of toes (vs. lateral fringes wide). Leptobrachella verrucosa sp. nov. differs from L. flaviglandulosa by having continuous longitudinal ridges under toes (vs. interrupted), heels not meeting when adpressed (vs. heels meeting).

Compared with the 26 known congeners of the genus Leptobrachella occurring south of the Isthmus of Kra, by the presence of supra-axillary and ventrolateral glands, L. verrucosa sp. nov. 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 , all of which lack supra-axillary and ventrolateral glands; and by its distinctly larger male body size, SVL 23.2-25.9 mm, L. verrucosa sp. nov. differs from the smaller L. baluensis (SVL 14.9-15.9 mm), L. brevicrus (SVL 17.1-17.8 mm), L. bondangensis (SVL 17.8 mm), L. fusca (SVL 16.3 mm), L. itiokai (SVL 15.2-16.7 mm), L. juliandringi (SVL 17.0-17.2 mm), L. mjobergi (SVL 15.7-19.0 mm), L. natunae (SVL 17.6 m), L. parva (SVL 15.0-16.9 mm), and L. palmata (SVL 14.4-16.8 mm); and even distinctly larger than female L. serasanae (SVL 16.9 mm).

In having black spots on flanks, Leptobrachella verrucosa sp. nov. further differs from L. aerea , L. botsfordi , L. crocea , L. firthi , L. isos , L. pallida , L. petrops , and L. tuberosa , all of which lack black spots on the flanks.

For the remaining 54 members of the genus Leptobrachella , males of the new species (SVL 23.2-25.9 mm) differs from males of the larger L. bijie (29.0-30.4 mm), L. chishuiensis (30.8-33.4 mm), L. bourreti (27.4-36.2 mm), L. damingshanensis (33.6-34.4 mm), L. dorsospina (28.7-30.5 mm), L. eos (33.1-34.7 mm), L. fuliginosa (28.2-30.0 mm), L. jinshaensis (29.7-31.2 mm), L. macrops (28.0-29.3 mm), L. nahangensis (40.8 mm), L. namdongensis (30.9 mm), L. pelodytoides (27.5-32.3 mm), L. purpuraventra (27.3-29.8 mm), L. pyrrhops (30.3-33.9 mm), L. suiyangensis (28.7-29.7 mm), L. sungi (48.3-52.7 mm), L. yunyangensis (28.3-30.6 mm), and L. zhangyapingi (48.5-52.5 mm). Through its possession of toes with rudimentary webbing and narrow lateral fringes, the new species can be distinguished from L. ardens , L. kalonensis , L. maculosa , L. neangi , L. rowleyae , L. shiwandashanensis , and L. tadungensis (no webbing); male L. alpina , L. graminicola , L. khasiorum , L. murphyi , L. purpurus , and L. yingjiangensis (wide lateral fringes); L. applebyi , L. lateralis , L. melica , L. minima , L. nyx , L. oshanensis , L. pluvialis , and L. ventripunctata (no lateral fringes). In having shagreened dorsal surface with numerous conical tubercles, lacking spines, enlarged warts or skin ridges, it can be distinguished from L. aspera , L. feii , L. nokrekensis , L. puhoatensis , L. tengchongensis , L. wuhuangmontis , and L. wulingensis (dorsum with skin ridges). In having creamy white ventral surface with grayish white and dark brown spots, it can be distinguished from L. bidoupensis (ventral surface reddish brown), L. niveimontis (ventral surface marbling), L. shangsiensis (ventral surface yellowish creamy-white with marble patterns), and L. tamdil (abdominal region unpatterned). In having continuous longitudinal ridges under toes, it can be distinguished from L. yeae (longitudinal ridges under toes interrupted).

Figures

Figure 1. Localities of Leptobrachella species occurring in Guangdong Province and Hong Kong, China: Leptobrachella verrucosa sp. nov. (samples ID 1 - 5, Lianshan Bijiashan Nature Reserve, Lianshan county); L. mangshanensis (sample ID 19, Nanling Nature Reserve, Ruyuan county; sample ID 20, Mt. Tianjing, Ruyuan county; sample ID 21, Mt. Dadong, Lianxian county; samples ID 22 - 23, Shimentai Nature Reserve, Yingde city); L. liui (sample ID 13, Mt. Tongguzhang, Fengshun county; sample ID 14, Mt. Fenghuang, Chaozhou city; sample ID 15, Mt. Motianshi, Puning city; sample ID 16, Baipenzhu, Huidong county; sample ID 17, Mt. Nankun, Longmen county); L. laui (sample ID 24, Tai Mo Shan, Hong Kong; sample ID 25, Mt. Wutong, Shenzhen city; sample ID 26, Mt. Paiya, Shenzhen city); L. shimentaina (sample ID 65, Shimentai Nature Reserve, Yingde city; sample ID 66, Luokeng Nature Reserve, Qujiang district); and L. yunkaiensis (sample ID 73, Mt. Yunkai, Xinyi city). Numbers correspond to the ID numbers in Suppl. material 1: Table S 1.

Figure 2. Bayesian inference Maximum Likelihood tree results from partial DNA sequences of the mitochondrial 16 S r RNA gene. Numbers before slashes indicate bootstrap support (BS) and numbers after slashes are Bayesian posterior probabilities (BPP). The ' - ' represent BS ≤ 70 or BPP ≤ 0.90. Voucher before species name at the branch terminal corresponds to the voucher ID in Suppl. material 1: Table S 1.

Figure 3. Morphological features of the holotype of Leptobrachella verrucosa sp. nov., GEP a 062 in life: A. Dorsal view; B. Dorsolateral view; C. Lateral view; D. Ventral view; E. Ventral view of hand; F. Ventral view of foot.

Figure 4. Morphological features of the paratypes of Leptobrachella verrucosa sp. nov., in life: A. GEP a 059 (A 1 dorsal view, A 2 lateral view, A 3 ventral view); B. GEP a 060 (B 1 dorsal view, B 2 dorsolateral view, B 3 ventral view); C. GEP a 061 (C 1 dorsal view, C 2 dorsolateral view, C 3 ventral view); D. GEP a 063 (D 1 dorsal view, D 2 dorsolateral view, D 3 ventral view).