Boulenophrys daxuemontis Liu, Li, Cheng, Wei, Wang & Cheng, 2025

Liu, Jing, Li, Shize, Cheng, Yanlin, Wei, Gang, Wang, Bin & Cheng, Gang, 2025, A new species of the genus Boulenophrys (Anura, Megophryidae) from Southwest China, Biodiversity Data Journal 13, pp. e 153987-e 153987 : e153987-

Boulenophrys daxuemontis Liu, Li, Cheng, Wei, Wang & Cheng sp. nov.

The specific name daxuemontis refers to the distribution of this species, Daxue Mountain, Sichuan province, China.

Materials

Type status: Holotype. Occurrence: recordedBy: Shi-Ze Li; sex: male; lifeStage: adult; occurrenceID: B17C4CFE-F2A9-5602-B987-2E04FCCD6FF8; Taxon: scientificName: Boulenophrys daxuemontis ; kingdom: Animalia; phylum: Chordata; class: Amphibia; order: Anura ; family: Megophryidae ; genus: Boulenophrys ; Location: country: China; stateProvince: Sichuan; county: Junlian; verbatimElevation: 1455 m; decimalLatitude: 27.8952; decimalLongitude: 104.7665; Event: eventDate: 2023-06-30; Record Level: institutionID: CIB JL 20230630024; collectionID: JL 20230630024

Type status: Paratype. Occurrence: recordedBy: Jing Liu; sex: male; lifeStage: adult; occurrenceID: 1B786FBC-55CE-509D-AE49-A57438C826FE; Taxon: scientificName: Boulenophrys daxuemontis ; kingdom: Animalia; phylum: Chordata; class: Amphibia; order: Anura ; family: Megophryidae ; genus: Boulenophrys ; Location: country: China; countryCode: Sichuan; county: Junlian; verbatimElevation: 1455 m; decimalLatitude: 27.8952; decimalLongitude: 104.7665; Identification: identifiedBy: Shi-ze Li; Event: eventDate: 2023-6-30; Record Level: institutionID: CIB JL 20230630025, CIB JL 20230630026; collectionID: JL 20230630025, JL 20230630026

Type status: Paratype. Occurrence: recordedBy: Jing Liu; occurrenceID: 64D3CC95-DC9F-5164-AEE4-FEFA569996EC; Taxon: scientificName: Boulenophrys daxuemontis ; kingdom: Animalia; phylum: Chordata; class: Amphibia; order: Anura ; family: Megophryidae ; genus: Boulenophrys ; Location: country: China; stateProvince: Yunnan; county: Weixin; verbatimElevation: 1495 m; decimalLatitude: 27.8879; decimalLongitude: 104.7695; Identification: identifiedBy: Shi-ze Li; Event: eventDate: 2023-06-30; Record Level: institutionID: CIB WX 20230630006, CIB WX 20230630007; collectionID: WX 20230630006, WX 20230630007

Description

Description of holotype (Fig. 2 , Fig. 3 ). SVL 37.7 mm; head width larger than head length (HDW / HDL ratio about 1.1); snout obtusely pointed, protruding well beyond the margin of the lower jaw in ventral view; loreal region vertical and concave; canthus rostralis well-developed; top of head flat in dorsal view; eye large, eye diameter 38.7 % of head length; pupils vertical; nostril rounded, distinct, closer to snout than eye; tympanum distinct, TYP / EYE ratio 0.49; Vomerine ridges are distinctly V-shaped, and vomerine teeth are absent; have maxillary teeth; margin of tongue smooth, not notched behind; adult males have a single subgular vocal sac.

Forelimbs slender, the length of lower arm and hand 42.1 % of SVL; fingers burly, relative finger lengths: II <I <V <III; tips of digits globular, without lateral fringes; subarticular tubercle distinct at the base of each finger; two metacarpal tubercles, oval-shaped, the inner one bigger than the outer one.

Hindlimbs slender, 1.4 times of SVL; heels overlapping when thighs are positioned at right angles to the body, tibiotarsal articulation reaching the level of middle eye when leg stretched forward; tibia length longer than thigh length; relative toe lengths I <II <V <III <IV; tips of toes round, slightly dilated; subarticular tubercles present on the base of each toe; toes without interdigital webbing and lateral fringe; inner metatarsal tubercle long ovoid and outer metatarsal tubercle absent; dense nuptial spines on dorsal bases of fingers I and II in breeding adult males.

Dorsal skin rough, numerous granules scattered on the surface of the head, the dorsum and the limbs; several large warts scattered on flanks; tubercles on the dorsum forming a X-shaped ridge; two discontinuous dorsolateral parallel ridges on either side of the X-shaped ridges; an inverted triangular brown speckle between two upper eyelids; single horn-like prominent tubercle on edge of upper eyelid; supratympanic fold distinct; temporal region excluding tympanum, upper eyelid and surface around cloaca with conical tubercles; surface of throat, chest and abdomen smooth; dense rounded tubercles on ventral thighs; small pectoral gland closer to axilla and bigger femoral gland positioned on posterior surface of thigh at midpoint between knee and cloaca.

Colouration of holotype in life. (Fig. 2 ). Dorsal surfaces of head and trunk brownish-yellow; an inverted triangular brown speckle between the eyes; X-shaped ridges on central dorsum; supratympanic fold light brown; three light brown transverse bands on dorsal surfaces of thigh and shank; 4 dark brown and white vertical bars on lower and upper lip; dark vertical band below eye; throat, anterior chest and surface of limbs light purple-brown; anterior belly light grey and posterior white and large black patches on belly sides, forming a discontinuous line; some white granules on the ventral surfaces of hindlimbs; dorsal surfaces of hind limbs and toes light brown with orange spots and dark brown transverse bands; palms and ventral surfaces of toes black-brown and the tip of fingers grey-white.

Colouration of holotype in preservation. (Fig. 3 ). After preservation in ethanol, dorsal surfaces light brownish grey; X-shaped ridges on dorsum indistinct and inverted triangular brown speckle between the eyes, transverse bands on limbs and digits distinct; surface of throat and anterior chest dark black-brown; anterior belly light grey-white and posterior belly grey-white; inner thigh, and upper part of tibia milky yellow; palms, ventral surfaces of soles and toes dark brown; inner metatarsal tubercle milky yellow.

Variation. (Fig. 4 ). In specimen CIB WX 20230630007 the dorsolateral parallel ridges are short, the dark - brown colour patches are darker, and the abdominal spots are lighter and whiter (Fig. 4 A, B); in specimen CIB JL 20230630025 the colour patches on the back are lighter, making the " X - shaped ridges " more prominent, the warts on the sides are denser (Fig. 4 C), the black spots on the abdomen are smaller, and the white spots on the inner side of the legs are sparser (Fig. 4 D); in specimen CIB JL 20230630026 the ridges on the back are shorter, and the warts on the sides are denser (Fig. 4 E), the black patches on the abdomen are larger and cover the entire abdomen, the posterior ends of both sides of the abdomen and the outer sides of the thighs exhibit an orange-red colour. (Fig. 4 F).

Comparisons. Boulenophrys daxuemontis sp. nov. can be distinguished from B. binlingensis , B. caudoprocta , B. fanjingmontis , B. jingdongensis , B. mirabilis , B. omeimontis , B. qianbeiensis , B. sangzhiensis , B. shuichengensis , B. spinata by having a medium body size in males (maximum SVL <41.0 mm in males vs minimum SVL> 45.0 mm in all other species). And differs from B. acuta , B. angka , B. cheni , B. daiyunensis , B. elongata , B. frigida , B. gaolanensis , B. hengshanensis , B. hungtai , B. kuatunensis , B. mufumontana , B. rubrimera , B. sanmingensis , B. shimentaina , B. tongboensis and B. wuliangshanensis by having a medium body size in males (minimum SVL> 37.0 mm in males vs maximum SVL <33.0 mm in all other species) (Suppl. material 1).

Boulenophrys daxuemontis sp. nov. can be distinguished from B. acuta , B. caudoprocta , B. jinggangensis , B. liboensis , B. mirabilis , B. palpebralespinosa and B. shuichengensis by having a small horn-like tubercle at the edge of each upper eyelid vs. having a prominent and elongated tubercle in the latter. And differs from B. binchuanensis , B. binlingensis , B. minor , B. spinata , B. wuliangshanensis and B. wushanensis by having a small horn-like tubercle at the edge of each upper eyelid vs. absent in the latter.

Boulenophrys daxuemontis sp. nov. can be distinguished from B. acuta , B. anlongensis , B. baishanzuensis , B. binchuanensis , B. boettgeri , B. cheni , B. congjiangensis , B. daiyunensis , B. daoji , B. fanjingmontis , B. jingdongensis , B. jinggangensis , B. kuatunensis , B. liboensis , B. lini , B. lushuiensis , B. mirabilis , B. mufumontana , B. nanlingensis , B. omeimontis , B. palpebralespinosa , B. qianbeiensis , B. rubrimera , B. sangzhiensis , B. sanmingensis , B. shimentaina , B. shuichengensis , B. spinata , B. wushanensis , B. xiangnanensis and B. yangmingensis by toes without lateral fringes vs. toes with lateral fringes in the latter.

Boulenophrys daxuemontis sp. nov. can be distinguished from B. acuta , B. angka , B. anlongensis , B. binchuanensis , B. binlingensis , B. boettgeri , B. brachykolos , B. caobangensis , B. caudoprocta , B. cheni , B. congjiangensis , B. daiyunensis , B. daoji , B. dongguanensis , B. dupanglingensis , B. fanjingmontis , B. fengshunensis , B. hengshanensis , B. insularis , B. jingdongensis , B. jinggangensis , B. jiulianensis , B. leishanensis , B. liboensis , B. lini , B. lushuiensis , B. minor , B. mirabilis , B. mufumontana , B. nankunensis , B. nanlingensis , B. obesa , B. omeimontis , B. palpebralespinosa , B. puningensis , B. qianbeiensis , B. sangzhiensis , B. sanmingensis , B. shimentaina , B. shuichengensis , B. shunhuangensis , B. spinata , B. tuberogranulata , B. wugongensis , B. wushanensis , B. xianjuensis , B. xiangnanensis , B. xuefengmontis , B. yangmingensis , B. yaoshanensis , B. yingdeensis and B. yunkaiensis by toes without webbing vs. having rudimentary webbing or most one-fourth webbed.

Boulenophrys daxuemontis sp. nov. is phylogenetically closest to B. jiangi ， in the same branch as B. chishuiensis and B. minor . This new species could be distinguished from B. jiangi distinctly by tibiotarsal articulation reaching the level of middle eye (vs. between tympanum to eye), relative finger lengths: II <I <V <III (vs. I <II <V <III), vomerine ridges present (vs. absent) and having significantly higher ratios of IOD to SVL and lower ratios of ED, TL and FL to SVL (Table 4 ). This new species could be identified from B. chishuiensis distinctly by having smaller body size SVL 37.1-40.6 mm in males (vs. SVL 43.4-44.1 mm in males); tibiotarsal articulation reaching the level of middle eye (vs. between tympanum to eye). This new species could be identified from B. minor distinctly by relative finger lengths: II <I <V <III (vs. I = II <V <III), tongue not notched behind (vs. notched in the latter), toes without webbing (vs. having rudimentary webbing). Suppl. material 1

Secondary sexual characters. Adult males have a single subgular vocal sac and dense nuptial spines on dorsal bases of fingers I and II in breeding adult males (Fig. 2 C).

Diagnosis

Boulenophrys daxuemontis sp. nov. is assigned to the genus Boulenophrys based on molecular phylogenetic analyses and the following generic diagnostic characters: snout shield-like; projecting beyond the lower jaw; canthus rostralis distinct; chest glands small and round, closer to the axilla than to midventral line; femoral glands on rear part of thigh; vertical pupils ( Fei et al. 2016).

Boulenophrys daxuemontis sp. nov. can be distinguished from its congeners by a combination of the following morphological characters: (1) body size moderate (SVL 37.1-40.6 mm in males); (2) vomerine ridge present and vomerine teeth absent; (3) tongue not notched behind; (4) a small horn-like tubercle at the edge of each upper eyelid; (5) tympanum distinctly visible, rounded; (6) toes without lateral fringes and webbing; (7) heels overlapped when thighs are positioned at right angles to the body; (8) tibiotarsal articulation reaching the level of middle eye when leg stretched forward; (9) an internal single subgular vocal sac in male; (10) dense nuptial spines on dorsal bases of fingers I and II in breeding adult males.

Etymology

The specific name daxuemontis refers to the distribution of this species, Daxue Mountain. We propose the common name “ daxueshan horned toad ” (English) and 大雪山角蟾 (Chinese).

Distribution

Boulenophrys daxuemontis sp. nov. is known from the Daxue Mountain, which is situated at the border between Sichuan and Yunnan provinces in China; it was collected at elevations between 1400–1500 m. The species is distributed in the Daxueshan Nature Reserve, where the habitat features dense vegetation and high forest coverage. Due to its remote location, the intensity of human disturbance is relatively low. During several days of field surveys, Boulenophrys daxueshanensis sp. nov. was found on both sides of Daxueshan Mountain, indicating that it occupies a specific distribution area within the reserve. No distinct vocalisations were heard at several distribution sites, and while other sympatric species have larger populations, no tadpoles or other life stages were found during the surveys, suggesting that the population size of this species is small. Therefore, population surveys and conservation efforts should be strengthened.

Ecology

The individuals of the new species were frequently found on stones in the streams surrounded by evergreen broadleaved forests (Fig. 5 ), and tree sympatric amphibian species, i. e. B. qianbeiensis ( Su et al. 2020) , Quasipaa boulengeri ( Günther 1889) and Leptobrachella bijie Wang, Li, Li, Chen, and Wang, 2019 were found. The survey was conducted from 8 to 10 p. m. on an overcast, rainy day, with air humidity ranging from 85 % to 95 % and a temperature of approximately 16 ° C. The habitat streams had a gravel substrate, narrow width, but significant elevation drop, resulting in fast-flowing water with distinct rushing sounds. While various frog calls were audible near the habitat — particularly the pronounced and intense vocalisations of Leptobrachella bijie , which overwhelmed other sounds — no valid vocalisations of the new species were collected. Extensive searches in multiple nearby streams and gullies failed to detect tadpoles of the new species.

Figures

Figure 2. Photos of the adult male holotype CIB JL 20230630024 of Boulenophrys daxuemontis sp. nov. in life. A dorsal view; B ventral view; C dorsal view of hand showing nuptial pads on the first and second fingers (1); D ventral view of hand; E ventral view of foot.

Figure 3. The holotype specimen CIB JL 20230630024 of Boulenophrys daxuemontis sp. nov. in preservation. A dorsal view; B ventral view; C dorsal view of right hand; D ventral view of right hand; E ventral view of right foot.

Figure 4. Color variation in Boulenophrys daxuemontis sp. nov. Dorsal and ventral views of male specimen CIB WX 20230630007 (A, B); dorsal and ventral views of male specimen CIB JL 20230630025 (C, D); dorsal and ventral views of male specimen CIB JL 20230630026 (E, F).

Figure 5. Habitats of Boulenophrys daxuemontis sp. nov. in the type locality, Daxue Mountain, Junlian County, Sichuan Province, China. A landscape of montane forests in the type locality; B the new species inhabits a mountain stream that is completely covered by vegetation.