Leptobrachella wumingensis, Chen & Peng & Li & Yu, 2023

Chen, Wei-Cai, Peng, Wan-Xiao, Li, Peng & Yu, Gui-Dong, 2023, A new species of the genus Leptobrachella Smith 1925 (Amphibia, Anura, Megophryidae) from Guangxi, China, ZooKeys 1178, pp. 1-16 : 1

Leptobrachella wumingensis sp. nov.

Figs 4 , 5

Type materials.

Holotype. NNU 01058, adult male, collected at the Damingshan National Nature Reserve, Wuming District, Nanning City, Guangxi, China (23.507°N, 108.395°E; elevation 1214 m), collected by Wei-Cai Chen on 12 April 2023. Paratypes. NNU 201907009, NNU 01086, two adult males, collected at the same locality as the holotype; NNU 201907009 collected by Gui-Dong Yu on 23 May 2019, NNU 01086 collected by Wei-Cai Chen on 14 April 2023; NNU 00283-6, four adult females collected at the same locality as the holotype on 16 June 2021 by Wei-Cai Chen; NNU 01059-60, two adult females collected at the same locality as the holotype on 12 April 2023 by Wei-Cai Chen.

Etymology.

The specific name ' wumingensis ' is derived from the type locality, Wuming District, Nanning City, Guangxi, China. The proposed common name in English is Wuming Leaf Litter Toad, and in Chinese, it is called Wu Ming Zhang Tu Chan (武鸣掌突蟾).

Diagnosis.

Leptobrachella wumingensis sp. nov. is classified under Leptobrachella based on specific morphological features, including its relatively small body size, presence of an inner metacarpal tubercle, macro-glands on the supra-axillary and femoral glands, lack of vomerine teeth, and a whitish vertical bar on the anterior tip of the snout, according to previous studies ( Dubois 1983; Lathrop et al. 1998; Delorme et al. 2006; Matsui 2006). Leptobrachella wumingensis sp. nov. can be differentiated from other species in its genus by a combination of the following characters: (1) medium size (SVL 26.0-26.7 mm in males, 30.6-34.8 mm in females); (2) absence of toe webbing and lateral fringes; (3) shagreened and granular dorsal surface; (4) pale brown dorsum with darker brown markings; (5) iris bicolored, with the upper half copper and fading to silver in the lower half; (6) presence of small irregular black spots and tangerine tubercles on the flanks; and (7) two types of advertisement callings and high dominant frequencies.

Description of holotype.

Head length almost equal to width (HW/HL = 1.02); snout bluntly rounded in profile and dorsal view, projecting slightly over lower jaw; nostril oval-shaped, closer to tip of snout than eye; canthus rostralis distinct; loreal region distinctly sloping, slightly concave; pupil vertical; eye diameter less than snout length (ED/SNT = 0.96); tympanum distinct and rounded, diameter about 49% that of eye; vomerine teeth absent; tongue with a deep notch at posterior tip; supratympanic fold distinctly raised from corner of eye to the posterior of tympanum (Fig. 4A-D ).

Tips of fingers slightly swollen; relative finger lengths I <II <IV <III; subarticular tubercles absent; prominent inner palmar tubercle, small outer palmar tubercle; finger webbing and dermal fringes absent; nuptial pad on fingers absent. Tips of toes rounded, slightly swollen; relative toe lengths I <II <V = III <IV; subarticular tubercles absent, replaced by dermal ridges; prominent and elongated inner metatarsal tubercle; outer metatarsal tubercle absent; toe webbing and lateral fringes absent. Tibia 48% of SVL; tibiotarsal articulation reaching middle of eye; heels meeting when hindlimbs flexed at right angles with respect to body (Fig. 4E, F ).

Dorsal surface shagreened and granular; upper eyelid with small tubercles; ventral surface without tubercles; flanks with sparse tubercles; pectoral glands elongated, approximately 2.1 mm in diameter; small femoral glands oval, approximately 0.6 mm in diameter, closer to knee than to vent; supra-axillary glands oval, approximately 0.8 mm in diameter; ventrolateral glandular line discrete; ventral surface of thigh with some tubercles (Fig. 4A-D ).

Color in life.

Dorsum light brown with brown markings, an inverted triangle marking between eyes, an irregular brown marking on scapular region, a brown ‘Λ’ marking on rear of dorsum; tympanum pale brown; supratympanic fold black from the posterior corner of eye to the anterior of supra-axillary glands; two wide black bars on upper lip; five irregular black spots and several small light tangerine tubercles on flanks; transverse brown bars on dorsal surface of hindlimbs; upper arms light orange; belly with tiny creamy white spots; throat creamy white with tiny light brown spots; lower jaw with creamy white tubercles; ventral surfaces of limbs with sparse creamy white tubercles; pectoral and femoral glands creamy white, supra-axillary glands light orange; pupil black; iris bicolored, upper half copper, fading to silver in lower half (Fig. 4A-D ).

Color in preservative.

The dorsum and limb surfaces are faded to uniform light brown. Irregular black spots on flanks and bars on limbs are darkish brown. The throat, chest, and belly are creamy white, and pectoral, femoral, supra-axillary, and ventrolateral glands are also creamy white.

Variation.

The measurements of the type series are shown in Table 2 . The holotype and paratypes exhibit similar color patterns. Females are larger than males in terms of body size. The number of black spots on the flanks varies, ranging from five to eight (Fig. 5A, B ). Some individuals have more tubercles on their flanks and their dorsum are rougher compared to the holotype (Fig. 5C ).

Ecology and distribution.

Leptobrachella wumingensis sp. nov. inhabits evergreen forests in the DMS at elevations of 1000-1200 m. All specimens were discovered over 10 m away from rocky streams (Fig. 5D, E ). The species’ advertisement calls were heard on the rocks in mid-April, and creamy white eggs were found on females’ abdomens in April (Fig. 5F ). We dissected four females collected in June and found no eggs in their abdomens. We speculate that the breeding period of the new species is between April and May. Since 2019, we have surveyed over ten rocky streams similar to the type locality but failed to find more sites where the new species occurs. The population of the new species is very rare; we have visited the type locality more than ten times since 2019, but only encountered nine adults. Although both L. wumingensis sp. nov. and L. damingshanensis occur in the DMS, the two species do not inhabit the same streams, and the closest site where both species are found is 10 km away. Currently, L. wumingensis sp. nov. is only known to occur in the DMS (Fig. 1 ).

Comparisons.

To begin with, L. wumingensis sp. nov. is distinguished from Leptobrachella species found south of the Isthmus of Kra, Malay Peninsula by the presence of supra-axillary and ventrolateral glands (vs absent in the latter). Furthermore, Leptobrachella wumingensis sp. nov. and L. damingshanensis are sympatric. Leptobrachella wumingensis sp. nov. can be differentiated from L. damingshanensis by several characters, including smaller body size in males (SVL 26.0-26.7 mm vs 33.6-34.4 mm); indistinct orange glands on the proximal thigh area (vs a pair of distinct tangerine glands on the proximal thigh area); pale brown dorsal skin with brown markings and a shagreened and granular dorsal surface (vs rough dorsal skin with sparse tangerine tubercles and some short longitudinal ridges); the absence of toe webbing and lateral fringes on toes (vs rudimentary toes webbing and narrow lateral fringes on toes); distinct transverse dark brown bars on the dorsal surface of hindlimbs (vs indistinct transverse dark brown bars on the dorsal surface of hindlimbs); and different bioacoustics, including two types of calling models and dominant frequency at 6.0-7.5 kHz (vs a single calling model and dominant frequency at 4.6-5.2 kHz) (Fig. 4 , Suppl. material 1: table S3).

According to the phylogenetic analysis, L. wumingensis sp. nov., L. damingshanensis , L. nahangensis , and L. nyx constitute a monophyletic group (Fig. 2 ). In terms of morphology, L. wumingensis sp. nov. can be differentiated from L. nahangensis by its notably smaller body size in males (SVL 26.0-26.7 mm vs SVL 40.8 mm); lack of toe webbing (vs rudimentary toes webbing); pale brown dorsum with brown markings, a triangle-shaped marking between the eyes, an irregular brown marking on the scapular region, and a brown ‘Λ’ marking on the posterior dorsum (vs dorsum covered with irregular, diffuse dark gray and black spots); and iris that is bicolored, with the upper half copper and the lower half fading to silver (vs uniformly gold iris). Similarly, L. wumingensis sp. nov. differs from L. nyx in lacking toe webbing (vs rudimentary toes webbing); pale brown dorsum with brown markings, a triangle-shaped marking between eyes, an irregular brown marking on the scapular region, and a brown ‘Λ’ marking on the posterior of dorsum (vs dorsum being greyish brown with dark regularly set rounded spots); and flanks with small, irregular black spots and tangerine tubercles (vs flanks with poorly distinct spots).

In comparison to other recognized Leptobrachella species from north of the Isthmus of Kra, L. wumingensis sp. nov. is distinguishable from smaller species such as L. applebyi (19.6-22.3 mm in males), L. ardens (21.3-24.7 mm in males), L. aspera (22.4 mm in male), L. feii (21.5-22.8 mm in males), L. korifi (22.7 mm in female), L. melica (19.5-22.7 mm in males), L. murphyi (23.2-24.9 mm in males), L. niveimontis (22.5-23.6 mm in males) and L. pluvialis (21.3-22.3 mm in males) due to its larger size (26.0-26.7 mm in males). Additionally, L. wumingensis sp. nov. is distinct from the notably larger L. sungi (48.3-52.7 mm in males) and L. zhangyapingi (45.8-52.5 mm in males).

Leptobrachella wumingensis sp. nov. can be distinguished from L. aerea , L. alpina , L. dong , L. eos , L. firthi , L. graminicola , L. isos , L. khasiorum , L. laui , L. liui , L. murphyi , L. purpurus , L. shimentaina , L. tamdil , L. yingjiangensis , L. yunkaiensis and L. zhangyapingi by the absence of lateral fringes on its toes (vs. wide lateral fringes); from L. aspera , L. bashaensis , L. bidoupensis , L. bijie , L. botsfordi , L. bourreti , L. chishuiensis , L. damingshanensis , L. dorsospina , L. feii , L. flaviglandulosa , L. fuliginosa , L. jinshaensis , L. jinyunensis , L. korifi , L. mangshanensis , L. maoershanensis , L. niveimontis , L. pelodytoides , L. petrops , L. puhoatensis , L. purpuraventra , L. shangsiensis , L. sinorensis , L. suiyangensis , L. sungi , L. tengchongensis , L. ventripunctata , L. verrucosa , L. wuhuangmontis , L. wulingensis , L. yeae , and L. yunyangensis by the absence of lateral fringes on its toes (vs. narrow lateral fringes). Leptobrachella wumingensis sp. nov. is also differentiated from L. aerea , L. botsfordi , L. crocea , L. graminicola , L. eos , L. firthi , L. isos , L. pallida , L. petrops , and L. tuberosa by the presence of black spots on its flanks (vs. absent). Leptobrachella wumingensis sp. nov. differs from L. applebyi , L. bidoupensis , L. kalonensis , L. melica , L. minima , L. nahangensis , and L. tadungensis by the presence of shagreened and granular dorsal surface (vs smooth).

Lastly, L. wumingensis sp. nov. differs from other Leptobrachella species in terms of acoustic features such as relatively high dominant frequencies and two distinct types of callings (Fig. 3 , Suppl. material 1: table S3).

Figures

Figure 1. Type locality of L. wumingensis sp. nov. (A) and its habitat (B).

Figure 2. BI trees based on the 16 S mtDNA fragments. Node support is indicated on branches as Bayesian posterior probabilities (upper half;> 0.95 = grey, 1 = black) and maximum likelihood support (lower half;> 70 % <90 % = grey,> 90 % = black).

Figure 3. Advertisement calls spectrograms of L. wumingensis sp. nov.

Figure 4. Morphological characters of L. wumingensis sp. nov. (NNU 01058) A dorsal view B ventral view C, D lateral view E ventral view of hand F ventral view of foot.

Figure 5. A dorsolateral view of NNU 01086 B dorsolateral view of NNU 01059 C dorsolateral view of NNU 00285 D NNU 201907009 in habitat (photo taken in situ) E NNU 00283 in habitat (photo taken in situ) F eggs (NNU 01059).