Leptobrachella cathaya sp. nov.

Huaping Leaf Litter Toad (in English) / Huā Píng Zhǎng Tū Chán (������������in Chinese)

Fig. 4

Holotype. NHMG 250615, adult male, collected by Jian Wang and Zhao-Chi Zeng on 23 June 2025 from Huaping National Nature Reserve (25.562769°N, 109.936686°E; ca. 1340 m a.s.l.), Longsheng County, Guilin City, Guangxi, China.

Paratypes. Four adult males, GEP a452–454, CIB 121750 (field number: GEP a455) and a single adult female, NHMG250616, same collection data as holotype. Two adult males, NHMG 250610 –11, collected by Zhong Huang on 25 June 2025, same collection site as holotype.

Etymology. The specific name is in reference to the monotypic botanic genus Cathaya Chun and Kuang, 1962. Guangxi Huaping National Nature Reserve is well known as the type locality of the endangered relict plant C. argyrophylla Chun and Kuang, 1962. We denominate the new toad species from this reserve in order to highlight the uniqueness of the flora and fauna here, also, to commemorate the contributions made by the predecessors.

Diagnosis. The new species can be diagnosed from its congeners by a combination of the following characters: (1) Small body size [SVL 25.0– 27.6 mm in seven adult males, 29.2 mm in a single adult female], (2) iris bicolored, upper half brown and lower half silver, (3) tympanum distinct, (4) supratympanic line weak, black, (5) fingers with narrow lateral fringes, (6) toes with narrow lateral fringes and rudimentary webbing, (7) longitudinal ridges under toes continuous, (8) heels overlapping when adpressed, tibial-tarsal articulation reaching the region from middle to anterior corner of eye, (9) dorsal surface shagreened with numerous small tubercles, lacking skin ridges, (10) ventral surface smooth, (11) dorsum yellowish brown to dark brown, with darker brown scattered markings and orange brown pigmentation, (12) flanks with several dark spots, (13) surface of throat, chest and abdomen creamy white, with sparse irregular dark brown speckles on chest and sides of abdomen, (14) white linea musculinae present in males.

Comparisons. Leptobrachella cathaya sp. nov. is a sister species to L. maoershanensis (Fig. 2). However, the new species differs from the later (Fig. 5) by its weak supratympanic line (vs. distinct), absence of skin ridges on dorsum (vs. present), and presence of lateral fringes on fingers (vs. absent).

Compared with the 27 known congeners of the genus Leptobrachella occurring south of the Isthmus of Kra, by the presence of supra-axillary and ventrolateral glands, L. cathaya 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. sarawakensis, L. sabahmontana, and L. sola, all of which lack supra-axillary and ventrolateral glands; by its distinctly larger male body size, SVL 25.0– 27.6 mm, L. cathaya 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 mm), 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); by its distinctly smaller body size, SVL 25.0– 27.6 mm in males, 29.2 mm in a single female, L. cathaya sp. nov. differs from the larger L. bourreti (39.5–45.0 mm in females), L. eos (40.7 mm in female), L. sungi (48.3–52.7 mm in males, 56.7–58.9 mm in females), and L. zhangyapingi (45.8–52.5 mm in males).

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

In having rudimentary webbing on toes, Leptobrachella cathaya sp. nov. differs from L. aurantirosea, L. ardens, L. batxatensis, L. duyenae, L. huynhi, L. jinshaensis, L. kalonensis, L. maculosa, L. oshanensis, L. shiwandashanensis, L. tadungensis, and L. wumingensis, and L. yachangensis, all of which lack webbing on toes; and from L. pelodytoides, and L. tamdil, both of which bear wide webbing on toes. In having narrow lateral fringes on toes, the new species differs from L. applebyi, L. darongshanensis, L. kungfu, L. lateralis, L. macrops, L. melica, L. minima, L. nahangensis, L. namdongensis, L. neangi, L. nyx, L. pluvialis, L. pyrrhops, L. rowleyae, L. ventripunctata, all of which lack lateral fringes on toes; from L. fuliginosa, which bears weak fringes on the first three and base of fourth and fifth toes; from L. sinorensis, which bears weak fringes laterally on the second and third toes; from L. dong, L. dushanensis, L. graminicola, L. guinanensis, L. khasiorum, L. murphyi, L. purpurus, L. shimentaina, L. yingjiangensis, and L. yunkaiensis, all of which bear wide lateral fringes on toes; and from L. alpina, L. laui, and L. liui, all of which bear wide lateral fringes on toes in males.

By the absence of skin ridges on dorsal surface, Leptobrachella cathaya sp. nov. differs from L. albomarginata, L. aspera, L. bijie, L. damingshanensis, L. dorsospina, L. korifi, L. mangshanensis, L. nokrekensis, L. phiadenensis, L. phiaoacensis, L. pingbianensis, L. purpuraventra, L. puhoatensis, L. wuhuangmontis, L. wulingensis, L. yunyangensis, L. yeae, L. xishuiensis, and L. yongshunensis, all of which bear skin ridges on dorsal surface. By the presence of narrow lateral fringes on fingers, the new species differs from L. bashaensis, L. bidoupensis, L. chishuiensis, L. dayaoshanensis, L. feii, L. flaviglandulosa, L. jinyunensis, L. niveimontis, L. shangsiensis, L. suiyangensis, L. tengchongensis, L. verrucosa, and L. weixinensis, all of which lack lateral fringes on fingers.

Description of holotype. Adult male. Body size small, SVL 27.6 mm. Head length slightly larger than head width, HDW/HDL 0.84; 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 1.21; pineal ocellus absent; pupil vertical; snout length equal to eye diameter; tympanum distinct, rounded, diameter smaller than that of eye and larger than tympanum-eye distance, TMP/EYE 0.50, TEY/TMP 0.47; 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 with narrow 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 overlapping when thighs are appressed at right angles with respect to body.

Dorsal surface shagreened with numerous small tubercles, lacking 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. Linea musculinae present, paired.

Coloration of holotype in life. Dorsal background color yellowish brown, with darker brown scattered markings and orange brown pigmentation. A dark brown inverted triangular marking in interorbital region, connecting to dark brown W-shaped marking on occipital region. Upper half of tympanum dark brown, lower half grayish brown. Supratympanic line weak, black. Transverse dark brown bars on dorsal surfaces of distal limbs and digits; distinct dark brown spots on flanks; surfaces of elbows, upper arms and tibiotarsal articulations coppery orange.

Surface of throat, chest and abdomen creamy white, with sparse irregular dark brown speckles on chest and sides of abdomen. Underside of limbs grayish white with numerous white dots. Supra-axillary and femoral glands orange, pectoral and ventrolateral glands creamy white. Iris bicolored, upper half brown and lower half silver. Linea musculinae white.

Coloration of holotype in preservative. Dorsal background color grayish brown; all markings, bars and spots become more distinct; orange brown pigmentation absent. Tympanum and supratympanic line dark brown.

Ventral surface of throat, chest, abdomen and limbs grayish white; irregular dark brown speckles more distinct. Supra-axillary, pectoral, and ventrolateral glands greyish white.

Variation. Morphometric variation is listed in Table 3. Dorsal coloration varies from yellowish brown to dark brown among individuals. Fewer irregular dark brown speckles on chest and sides of abdomen in the female paratype NHMG 250616 and denser in the male paratype GEP a453–455. Tibiotarsal articulation reaches to anterior corner of eye in the all males, and to middle of eye in the female paratype NHMG 250616.

Distribution and natural history. Currently, Leptobrachella cathaya sp. nov. is only known from its type locality. It inhabits flowing rocky montane streams (ca. 1–5 meters wide) and the nearby forest floor and leaf litter at elevations between 1200–1400 m (Fig. 6), with a large population size. Its breeding season lasts from May to July, i.e., the high-water period. The adult paratype, NHMG250616 collected on 23 June 2025 is a gravid female bearing creamy yellow oocytes. The ecological data of tadpoles is currently unknown. Although the new species is sympatric with L. dong, the breeding season of the latter appears different (from February to April, i.e., the lowwater period) (Huang et al. 2025a).