Leptobrachella dushanensis Li, Li, Cheng, Liu, Wei, Wang, 2024

Li, Shize, Li, Wei, Cheng, Yanlin, Liu, Jing, Wei, Gang & Wang, Bin, 2024, Description of a new Asian Leaf Litter Toad of the genus Leptobrachella Smith, 1925 (Anura, Megophryidae) from southern Guizhou Province, China, Biodiversity Data Journal 12, pp. 113427-113427 : 113427

Leptobrachella dushanensis Li, Li, Cheng, Liu, Wei, Wang sp. nov.

Materials

Type status: Holotype. Occurrence: recordedBy: Jing Liu; sex: male; lifeStage: adult; occurrenceID: B8B9E666-2D12-5015-8398-05CB6F244FCD; Taxon : scientificName: Leptobrachella dushanensis; kingdom: Animalia ; phylum: Chordata ; class: Amphibia ; order: Anura ; family: Megophryidae ; genus: Leptobrachella ; Location : country: China; stateProvince: Guizhou; county: Dushan ; decimalLatitude: 25.961719; decimalLongitude: 107.649194; Identification : identifiedBy: Shize Li ; Event : eventDate: 2022-04-09; Record Level: institutionID: MT DS20220409002; collectionID: DS 20220409002 Type status: Paratype. Occurrence: recordedBy: Jing Liu and Wei Li ; sex: 3 males; lifeStage: adult; occurrenceID: 83945396-6D45-5955-875D-54024A94F66A; Taxon : scientificName: Leptobrachella dushanensis; kingdom: Animalia ; phylum: Chordata ; class: Amphibia ; order: Anura ; family: Megophryidae ; genus: Leptobrachella ; Location : country: China; stateProvince: Guizhou; county: Dushan ; decimalLatitude: 25.961719; decimalLongitude: 107.649194; Identification : identifiedBy: Shize Li ; Record Level : type: Event ; institutionID: MT DS20220409001, MT DS20230310001 and MT DS20230310002; collectionID: DS20220409001, DS20230310001 and DS20230310002

Diagnosis

Leptobrachella dushanensis sp. nov. is assigned to the genus Leptobrachella , based on molecular data and the following morphological characters: medium size, rounded finger tips, the presence of two elevated inner palmar tubercle not continuous to the thumb, presence of macroglands on body (including supra-axillary, pectoral and femoral glands), vomerine teeth absent, tubercles on eyelids and anterior tip of snout with vertical white bar (Dubois 1983; Fei et al. 2009).

Leptobrachella dushanensis sp. nov. could be distinguished from its congeners by a combination of the following characters: body of medium size in males (SVL 31.9 - 32.9 mm); distinct black spots present on flanks; toes rudimentarily webbed, with wide lateral fringes; skin on dorsum shagreened with fine tiny granules and short ridges; heels overlapped when thighs are positioned at right angles to the body; tibia-tarsal articulation reaching interior corner of the eye.

Description of holotype

Adult male. SVL in 33.2 mm. Head length slightly wider than head width (HDL/HDW = 1.04); snout sharply rounded in dorsal view, projecting slightly beyond margin of the lower jaw; nostril closer to snout than eye; loreal region oblique; canthus rostralis indistinct; eyes large and convex (ED/HDL = 0.37), slightly shorter than snout length (ED/SL = 0.93), pupil vertical; tympanum distinct, rounded, tympanum diameter smaller than eye (TD/ED = 0.43), upper margin of tympanum in contact with supratympanic ridge; vomerine teeth absent; tongue notched behind; supratympanic ridge distinct, extending from posterior corner of eye to supra-axillary gland.

Fore-limb relatively long (LAL / SVL = 0.45), fingers long and slender (ML/SVL = 0.25), without webbing, lateral fringes on fingers narrow; relative finger lengths II <I <IV <III; tips of fingers rounded and slightly swollen; subarticular tubercles absent on fingers, inner metacarpal tubercle large and rounded, separated from the smaller, round outer metacarpal; supra-axillary glands oval.

Hind-limb relatively long (HLL/SVL = 1.56), heels overlapping when the tibiae perpendicular to the body axis; tibio-tarsal articulation of adpressed limb reaching interior corner of the eye, tibia length about half of snout-vent length (TL/SVL = 0.49); relative toe length: I <II <III <V <IV; toe tips rounded and slightly swollen; rudimentary webbing present between all five toes; wide lateral fringes present on all toes; subarticular tubercles indistinct on the base of toe; inner metatarsal tubercle oval and distinct, outer metatarsal tubercle absent.

Skin on dorsum shagreened with fine tiny granules and short ridges; supra-axillary glands long, oval, close to the armpit; pectoral gland indistinct; round femoral glands present and protuberant on rear of thigh, closer to knee than to vent; femoral adipose glands distinct, attached to inner side of skin on posterior ventral surface of thigh; ventral skin smooth; ventrolateral glands distinctly visible and raised, forming an incomplete line.

Colouration of holotype in life

In life, dorsal surface of head and trunk earth brown, with a distinct reverse-triangle taupe markings between eyes connecting to a taupe W-shaped marking between axillae that are fringed with greyish-white colour; very distinct, light brown markings between the nostrils; bicoloured iris, with the upper 1/3 of the iris being copper-orange and the lower 2/3 a light silvery-grey and a dark blotch under the eye; sparse, small, light brown granules and small dark brown patches present on the dorsum of the limbs; elbow to upper arm distinctly greyish-brown in colour on the dorsum; three transverse black bars present on dorsal surface of lower arm; distinct dark blotches on flanks from groin to axilla, longitudinally in two rows; ventral surfaces light coloured, throat and ventral arms pinkish, chest and belly cream-white and flanks of ventral with several granules and brown spots; ventral hind-limbs pinkish with sparse white glands (Fig. 2 ).

Preserved holotype colouration

Dorsum of body and limbs fade to brown; transverse bars on limbs become more distinct. Ventral surface of body and limbs fade to cream-white. Supra-axillary, femoral and pectoral glands fade to cream-yellow (Fig. 3 ).

Variations

Measurements of adult specimens are presented in Suppl. material 1 and Table 3 , respectively. In MT DS20230310001, dorsal surface of head and trunk reddish-brown (Fig. 4 A) and femoral adipose glands more obvious, ventral skin of thigh smooth (Fig. 4 B); in MT DS20230310002, the black bars on dorsum more obvious (Fig. 4 C) and glands on ventral surface of hind-limbs more dense (Fig. 4 D).

Comparisons

Compared with the 26 known congeners occurring south of the Isthmus of Kra, Leptobrachella dushanensis sp. nov. could be distinguished from them by several characters. By having supra-axillary and ventrolateral glands, the new species differs from L. arayai , L. dringi , L. fritinniens , L. gracilis , L. hamidi , L. heteropus , L. kajangensis , L. kecil , L. marmorata , L. maura , L. melanoleuca , L. picta , L. platycephala , L. sabahmontana and L. sola (vs. absent in the latter); by having rounded fingertips and moderate body size (31.9 - 32.9 mm in four adult males), the new species differs from the following species with pointed fingertips and smaller body size: L. baluensis (14.9-15.9 mm in males), L. bondangensis (17.8 mm in male), L. brevicrus (17.1-17.8 mm in males), 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. palmata (14.4-16.8 mm in males), L. parva (15.0-16.9 mm in males) and L. serasanae (16.9 mm in female).

Leptobrachella dushanensis sp. nov. could also be identified from 76 known Leptobrachella species occurring north of the Isthmus of Kra by some characters (Suppl. material 2).

By having medium size of body (SVL 31.9-32.9 mm in males), Leptobrachella dushanensis sp. nov. differs from the the smaller in males L. aerea (25.1-28.9 mm), L. alpina (24.0-26.4 mm), L. applebyi (19.6-22.3 mm), L. ardens (21.3-24.7 mm), L. aspera (22.4 mm), L. bashaensis (22.9-25.6 mm), L. bidoupensis (23.6-24.6), L. bijie (29.0-30.4), L. crocea (22.2-27.3 mm), L. dorsospina (28.7-30.5 mm), L. feii (21.5-22.8 mm), L. firthi (26.4-29.2 mm), L. flaviglandulosa (23.0-27.0 mm), L. fuliginosa (28.2-30.0 mm), L. graminicola (23.1-24.6 mm), L. isos (23.7-27.9 mm), L. khasiorum (24.5-27.3 mm), L. lateralis (26.9-28.3 mm), L. laui (24.8-26.7 mm), L. liui (24.8-26.7 mm), L. macrops (28.0-29.3 mm), L. maculosa (24.2-26.6 mm), L. mangshanensis (22.22-27.76 mm), L. maura (26.1 mm), L. melica (19.5-22.8 mm), L. murphyi (23.2-24.9 mm), L. niveimontis (22.5-23.6 mm), L. pallida (24.5-27.7 mm, L. petrops (23.6-27.6 mm), L. pingbianensis (28 mm), L. pluvialis (21.3-22.3 mm), L. puhoatensis (24.2-28.1 mm), L. purpuraventra (27.3-29.8 mm), L. purpurus (25.0-27.5 mm), L. rowleyae (23.4-25.4 mm), L. shangsiensis (24.9-29.4 mm), L. shiwandashanensis (26.8-29.7 mm), L. shimentaina (26.4-28.9 mm), L. sinorensis (26.6-27.1 mm), L. suiyangensis (28.7-29.7 mm), L. tadungensis (23.3-28.2 mm), L. tengchongensis (23.9-26.0 mm), L. tuberosa (24.4-29.5 mm), L. ventripunctata (23.7-27.7 mm), L. verrucosa (23.2-25.9 mm), L. wuhuangmontis (25.6-30.0 mm), L. wumingensis (26.0-26.7 mm), L. yingjiangensis (25.7-27.6 mm) and L. yunkaiensis (25.9-29.3 mm); differs from the larger in males L. nahangensis (40.8 mm), L. platycephala (35.1 mm), L. sungi (48.3-52.7 mm in males) and L. zhangyapingi (45.8-52.5 mm).

By having black spots on flanks, Leptobrachella dushanensis sp. nov. differs from L. aerea , L. botsfordi , L. crocea , L. eos , L. firthi , L. isos , L. pallida , L. petrops , L. tuberosa and L. zhangyapingi (vs. lacking distinct black spots on the flanks in the latter).

By having rudimentary webbing, Leptobrachella dushanensis sp. nov. differs from L. ardens , L. jinshaensis , L. kalonensis , L. maculosa , L. oshanensis , L. pallida , L. petrops , L. rowleyae , L. shiwandashanensis and L. tadungensis (vs. absent webbing in the latter).

By having wide fringes on toes, Leptobrachella dushanensis sp. nov. differs from L. applebyi , L. ardens , L. aspera , L. bashaensis , L. bidoupensis , L. bijie , L. botsfordi , L. bourreti , L. chishuiensis , L. crocea , L. damingshanensis , L. dorsospina , L. feii , L. flaviglandulosa , L. fuliginosa , L. jinshaensis , L. kalonensis , L. korifi , L. lateralis , L. macrops , L. maculosa , L. mangshanensis , L. melica , L. minima , L. nahangensis , L. namdongensis , L. niveimontis , L. nyx , L. oshanensis , L. pallida , L. pelodytoides , L. petrops , L. phiaoacensis , L. phiadenensis ,

L. pluvialis , L. puhoatensis , L. purpuraventra , L. pyrrhops , L. rowleyae , L. shangsiensis , L. sinorensis , L. shiwandashanensis , L. sungi , L. tengchongensis , L. tuberosa , L. ventripunctata , L. wuhuangmontis , L. wulingensis , L. wumingensis , L. yeae and L. yunyangensis (vs. fringes on toes narrow or absent in the latter).

By having dorsal surface shagreened with fine tubercles, Leptobrachella dushanensis sp. nov. differs from L. applebyi , L. bidoupensis , L. kalonensis , L. melica , L. minima , L. nahangensis , L. shangsiensis and L. tadungensis , all of which have the dorsum smooth and L. bourreti (dorsum smooth with small warts), L. fuliginosa (dorsum smooth with fine tubercles), L. liui (dorsum with round tubercles), L. macrops (dorsum roughly granular with large tubercles), L. maoershanensis (dorsum shagreened with tubercles), L. minima (dorsum smooth), L. neangi (dorsum with small, irregular bumps and ridges), L. nyx (dorsum with round tubercles), L. nokrekensis (dorsum tubercles and longitudinal folds), L. pelodytoides (dorsum with small, smooth warts), L. tamdil (dorsum weakly tuberculate, with low, oval tubercles), L. tuberosa (dorsum highly tuberculate), L. yunkaiensis (dorsum with raised warts) and L. wuhuangmontis (dorsum rough with conical tubercles).

In mitochondrial DNA trees, Leptobrachella dushanensis sp. nov. and L. dong clustered into one clade, being sisters. The new species differs from L. dong by the following characters: head length slightly wider than head width (vs. head width slightly wider than head length); males with internal single subgular vocal sac (vs. a pair of subgular internal vocal sacs); tibiotarsal articulation reaching to anterior edge of eye (vs. reaching to middle of eye).

Secondary sexual characteristics

Adult males with internal single subgular vocal sac, femoral adipose glands present on posterior surface of thigh and tiny transparent spines on chest during breeding season. Nuptial pads and spines absent on males.

Etymology

This specifc name “Dushan” refers to the distribution of this species in Dushan County, Guizhou Province, China. We suggest its English common name "Dushan leaf litter toad" and Chinese name "Dushan Zhang Tu Chan ( 独山掌突蟾)”.

Distribution

Leptobrachella dushanensis sp. nov. was only found in Dushan County, Guizhou Province, China. Elevations recorded range from 1000 m to 1200 m.

Ecology

Leptobrachella dushanensis sp. nov. was found under stones in fast-flowing mountain streams surrounded by evergreen broadleaf forest (Fig. 5 ) and we did not find eggs, nor tadpoles or females. Based on our surveys, we speculate that the breeding season is probably in late March.

Figures

Figure 2. Photos of the holotype CIB DS 20220409002 Leptobrachella dushanensis sp. nov. in life. A dorsolateral view; B ventral view; C dorsal view; D ventral view of hand E ventral view of foot.

Figure 3. The holotype specimen MT DS 20220409002 Leptobrachella dushanensis sp. nov. A dorsal view; B ventral view; C ventral view of hand; D ventral view of foot.

Figure 4. Colour variation in Leptobrachella dushanensis sp. nov. A dorsal view of the male specimen MT DS 20230310001; B ventral view of the male specimen MT DS 20230310001; C dorsal view of the male specimen MT DS 20230310002; D ventral view of the female specimen MT DS 20230310002.

Figure 5. Habitats of Leptobrachella dushanensis sp. nov. A landscape of the type locality Dushan County, Guizhou Province, China; B a mountain stream in the type locality.