Amolops cuongi, Pham & Van Hoang & Tapley & Nguyen & Nguyen & La & Ziegler & Rowley & Nguyen & Le, 2025

Pham, Anh Van, Van Hoang, Chung, Tapley, Benjamin, Nguyen, Luan Thanh, Nguyen, Hanh Huu, La, Toi Van, Ziegler, Thomas, Rowley, Jodi J. L., Nguyen, Truong Quang & Le, Minh Duc, 2025, Amolops cuongi (Amphibia, Anura, Ranidae), a new species from the Hoang Lien Range, Vietnam, ZooKeys 1256, pp. 235-257 : 235-257

Amolops cuongi sp. nov.

Figs 3 , 4 , 5 , 6

Type material.

Holotype. IEBR A.5139 (Field No. LC 2020.82), • adult male, collected by C. T. Pham, C. V. Hoang, T. V. Phan, N. B. Sung, and A. V. Pham on 16 May 2020, found in evergreen forest near Ho Thau Village , Ho Thau Commune, Lai Chau Province, Vietnam ( 22.408313°N, 103.608094°E, at an elevation of 2442 m) . Paratypes. In Lai Chau Province, Vietnam: • two adult females, IEBR A.5140 (Field No. LC 2020.179), IEBR A.5141 (Field No. LC 2020.181), the same data as the holotype . • one adult male ILS H.3665 (Figs 5 , 6 A ) and one adult female ILS H.3666 nd, collected in disturbed evergreen forest of Hoang Lien Range in ( 22.3473°N, 103.77226°E; 1928 m a. s. l.), on 10 September 2018 by L. T. Nguyen, C. T. Nguyen, and H. V. Luong . In Lao Cai Province, Vietnam: • specimens collected in the forest of Hoang Lien Range , near Sa Pa by L. T. Nguyen, C. T. Nguyen, B. Tapley and L. Harding: • one adult female ILS H.3662 (Fig. 6 E ) and one subadult ILS H.3663 (Fig. 6 G ) ( 22.31517°N, 103.76897°E; 2629 m a. s. l.) on 14 September 2017 ; • one adult female ILS H.3664 ( 22.31488°N, 103.76845°E; 2690 m a. s. l.) on 14 September 2017 ; collected by L. T. Nguyen, C. T. Nguyen and L. V. Hoang on 13 June 2018: • one adult male ILS H.3667 ( 22.3149°N, 103.7686°E; 2635 m a. s. l.) and one adult female ILS H.3668 ( 22.3145°N, 103.7675°E; 2685 m a. s. l.) ; • one adult female ILS H.3671 ( 22.31394°N, 103.76561°E; 2784 m a. s. l.), collected on 19 June 2019 by L. T. Nguyen and C. T. Nguyen ; One adult male ILS H.3674 and one subadult ILS H.3675 ( 22.31394°N, 103.76561°E; 2784 m a. s. l.), collected on 8 September 2019 by C. T. Nguyen ; • one adult female ILS H.3666 (Fig. 6 B ) ( 22.3473°N, 103.77226°E; 1928 m a. s. l.) collected on 10 September 2018 by L. T. Nguyen, C. T. Nguyen, and L. V. Hoang ; • one subadult ILS H.3669 ( 22.9474°N, 103.8030°E; 2578 ma. s. l.), collected on 14 September 2018 by L. T. Nguyen, C. T. Nguyen, and H V. Luong ; • three adult males ILS H.3683 (Fig. 6 C ), ILS H.3685 and ILS H.3686 and two adult females ILS H.3673 and ILS H.3684 (Fig. 6 D ) ( 22.14565°N, 103.96281°E; 2321 m a. s. l.) , one adult female ILS H.3672 ( 22.14087°N, 103.95631°E; 2311 m a. s. l.), collected in undisturbed evergreen forest on Mount Nam Kang Ho Tao , Sa Pa on 13 September 2020 by C. T. Nguyen, G. T. Hoang and Q. L. Tan ; • one adult male ILS H.3670 collected in disturbed evergreen forest on Mount Pu Ta Leng , Bat Xat ( 22.4263°N, 103.61322°E, 2362 m a. s. l.) on 22 March 2018 by C. T. Nguyen, L. T. Nguyen, B. Tapley and C. Portway .

Referred specimen.

One subadult HLNP 2017 1409 00030 (Fig. 6 F ) found in bamboo forest on Mount Fansipan , Sa Pa, Lao Cai Province, Vietnam ( N 22.31483, E 103.76883; 2625 m a. s. l.) on 14 September 2017 by L. T. Nguyen, C. T. Nguyen, B. Tapley, and L. Harding . This specimen is not included in the type series due to it being deposited in a local collection. The taxonomic identity of the specimen is not in question.

Diagnosis.

Amolops cuongi sp. nov. from the Hoang Lien Range is assigned to the A. mantzorum species group based on the absence of a dorsolateral fold and the absence of a circummarginal groove on the first finger ( Fei et al. 2009, 2017). The new species is also supported as a member of the A. mantzorum group based on the molecular analyses (Fig. 2 ).

Amolops cuongi sp. nov. is distinguishable from its congeners by a combination of the following morphological characteristics: (1) size small ( SVL 33.9–36.9 mm in males; 37.9–44.4 mm in females); (2) head longer than wide; (3) vomerine teeth absent or weakly developed; (4) snout short ( SE / SVL 0.15–0.17 in males; 0.14–0.16 in females); (5) tympanum small, round ( TD / ED 0.24–0.37 in males; 0.26–0.35 in females); (6) the absence of a circummarginal groove on the first finger; (7) width of disc of finger III larger than tympanum; (8) supratympanic fold present; (9) dorsolateral fold absent; (10) webbing formula I 0–1 II 0 – 1 III 0 – 1 IV 1 – 0 V; (11) the presence of a band of small spinules and / or tubercles running from below nares, along upper lip, around lower half of eye, between tympanum and eye and rear axis of mandibles; (12) granular skin on flanks and ventral surfaces of body; (13) in life, dorsal body colouration of dark brown with diffuse-edged blotches of bluish grey, copper and yellowish green or pale green and copper; (14) ventral surface of throat, chest and belly pale cream with white dots; (15) males without vocal sacs; and (16) nuptial pad velvety without spines.

Description of holotype.

Adult male; SVL 36.0 mm; head broad and flat (HD / SVL 0.14), longer than wide ( HL 12.2 mm, HW 11.8 mm, HL / SVL 0.34, HW / SVL 0.33); snout round anteriorly in dorsal view ( SE / SVL 0.15), projecting beyond lower jaw; snout length greater than eye diameter ( SE 5.0 mm, ED 5.3 mm); nostril lateral, closer to eye the than to snout tip ( SND 3.0 mm, END 2.3 mm); canthus rostralis distinct; loreal region slightly concave; eyes large ( ED / HL 0.43, ED / SE 1.0); pupil horizontally oval; internarial distance as wide as interorbital distance ( IND 4.2 mm, IOD 4.2 mm), larger than upper eyelid width (UEW 2.9 mm); tympanum distinct, round, small ( TD 1.5 mm, TD / ED 0.28); vomerine teeth absent; tongue cordiform, notched posteriorly; body gracile.

Fore limbs robust; relative finger lengths: I <II <IV <III; fingers without webbing; tips of fingers expanded into discs, II – IV with circummarginal grooves; tip of first finger smaller, without circummarginal groove; width of disc of finger III greater than the diameter of tympanum ( TD 1.5 mm, FTD 2.5 mm, TD / FTD 0.60); subarticular tubercles at base of fingers II – IV round, others indistinct; inner metatarsal tubercle oval, elongate, indistinct; outer metatarsal tubercle absent, finger I with a large nuptial pad, elongate, ~ 2 / 3 the length of finger.

Hind limbs long; tibia longer than thigh ( FL 17.9 mm, TL 20.2 mm); relative toe length I <II <III <V <IV; tips of toes expanded into discs; width of disc of toe IV narrower than that of finger III ( FTD 2.5 mm, HTD 1.6 mm); webbing formula I 0–1 II 0 – 1 III 0 – 1 IV 1 – 0 V; subarticular tubercles oval, formula 1, 1, 2, 3, 2; inner metatarsal tubercle elongate; outer metatarsal tubercle absent; tibiotarsal articulation reaches the nostril.

Skin texture in life.

Dorsal surface of head, body, and limbs smooth; posterior surface of thighs and ventral surfaces of shanks smooth; flanks, throat, chest, abdomen and ventral surfaces of forearms and thighs weakly granular with the granules largest on flanks; supratympanic folds present; dorsolateral folds absent; band of small spinules present running from below nares, along upper lip, around lower half of eye, between tympanum and eye and rear axis of mandibles, small spinules are largest between tympanum and eye and at rear axes of mandibles; tympanum smooth; limbs smooth on dorsal and ventral surfaces; humeral glands absent.

Colouration in life.

Dorsum green with some dark brown spots and some large pale green markings; dorsal surface of head and body with some irregular small black dots; lips pale green; loreal region with a dark brown longitudinal stripe, tip of snout green with small brown dots; around iris white; tympanum dark brown; dorsal surface of fore and hind limbs pale green with dark crossbars; flanks green; ventral surface of throat, chest and belly pale cream with white dots; ventral surface of fore and hind limbs pale brown with some greenish dots; back of the thigh brown with pale dots; plantar aspect of feet brown.

Colouration in preservative.

Dorsum and flanks brown with some large grey spots; lips brown; tympanum black; dorsal surface of fore and hind limbs brown with dark crossbars; throat and chest grey; belly grey-brown with pale dots; ventral surface of fore and hind limbs pale grey with pale dots; back of the thigh brown with grey dots; plantar surface of the foot brown.

Sexual dimorphism.

All adult males with a cream-coloured, velvety nuptial pad along base of finger I in preservative (Fig. 5 D ), greyish brown in life (Fig. 3 A, B ). Four gravid females ( ILS H.3684 , ILS H.3662 , ILS H.3664 , ILS H.3672 ); Eggs counted and measured in ILS H.3684 only: 44 yellow, round eggs ~ 3.2–3.4 mm in diameter ( n = 10 eggs). The presence of white spinules below nares, along upper lip, around lower half of eye, between tympanum and eye and rear axes of mandibles is present in both sexes. Body size of females greater than body size of males ( SVL of adult males 33.9–36.9 mm, n = 8; adult females 37.9–44.4 mm, n = 7).

Variation.

Morphometric measurements of the type series are shown in Table 1 and representative photographs of paratypes and referred specimen in life are shown in Fig. 6 . Specimens vary in body size and most dramatically in colouration in life (Fig. 6 ). Two paratypes ( ILS H.3665 ) and ILS H.3666 (Fig. 6 B ) have diffuse-edged blotches of bluish grey on their dorsal surfaces. The dorsal surfaces of ILS H.3683 (Fig. 6 C ) are dark brown with diffuse-edged blotches of yellowish green and copper and more distinct barring on the lateral surfaces of the hindlimbs. The dorsal surfaces of ILS and ILS H.3663 (Fig. 6 G ) are pale green and copper, and the dorsal surfaces of the body and limbs in HLNP 2017 1409 00030 (Fig. 6 F ) and ILS H.3662 (Fig. 6 E ) are almost entirely copper. The flanks of ILS H.3683 , ILS H.3684 , HLNP 2017 1409 00030 , ILS H.3662 , and ILS H.3663 are pale green with some faint brown blotches. Interdigital webbing colouration does not differ between the upper and lower surfaces but is variable between specimens and is pale yellow in ILS H.3683 , HLNP 2017 1409 00030 , ILS H.3662 and ILS H.3664 (versus greyish brown in other specimens in the series). The colouration of the ventral surface of head, throat, chest, and abdomen is also highly variable, creamy grey in ILS H.3666 , pale green in HLNP 2017 1409 00030 , ILS H.3662 , ILS H.3663 , ILS H.3664 , ILS H.3673 , ILS H.3683 , and ILS H.3684 . Colouration of ventral surface of hindlimbs variable, pale brown with white granules on thigh in HLNP 2017 1409 00030 and ILS H.3683 , pale brown with small white and pale yellow blotches on ventral surface of thigh in ILS H.3662 , pale brown in ILS H.3663 , pale brown with dense greenish cream small blotches in ILS H.3664 and ILS H.3673 , pale brown with dense greenish cream and bluish grey small blotches in ILS H.3664 and ILS H.3684 ; lip stripe colouration also variable, green in all individuals except holotype and ILS H.3666 . Iris colour is variable, gold and metallic orange with black reticulations in ILS H.3683 and ILS H.3684 , HLNP 2017 1409 00030 , ILS H.3662 , ILS H.3663 , ILS H.3664 . In ILS H.3662 , ILS H.3666 , ILS H.3673 ; ventral surfaces of throat, chest, belly, and abdomen only weakly granular, small spinules not present on in ILS H.3666 , ILS H.3673 , ILS H.3675 but there are small white tubercles in their place. ILS H.3684 with very dense area of white spinules almost extending to axilla, these are also present on the axilla in ventral view; vomerine teeth are weakly developed in ILS H.3671 , ILS H.3662 , ILS H.3664 , ILS H.3665 , ILS H.3672 , ILS H.3683 , ILS H.3673 and ILS H.3674 and not present in HLNP 2017 1409 00030 , ILS H.3663 , ILS H.3666 , ILS H.3675 , ILS H.3686 , ILS H.3684 , ILS H.3675 and ILS H.3670 .

Distribution.

Amolops cuongi sp. nov. is currently known only from the Hoang Lien Range in northern Vietnam, including Tam Duong, Lai Chau Province and Sa Pa and Bat Xat, Lao Cai Province (Fig. 1 ).

Etymology.

The new species is named after Dr. Cuong The Pham, our colleague from Institute of Biology, Vietnam to honour his contributions to the herpetological research in Vietnam, particularly in the taxonomy of the anuran species complexes. For the common names we suggest Cuong’s Torrent Frog (English) and Ếch bám đá cư ờng (Vietnamese).

Ecological notes.

Amolops cuongi sp. nov. is recorded from both disturbed and primary evergreen and bamboo forest with a relatively closed canopy (Suppl. material 2: fig. S 1). Nearly all individuals have been found at night, perched on streamside vegetation ≤ 2.5 m from the ground alongside clear, fast-moving water, along ca 3.0 m wide streams or waterfalls. The holotype was collected from a small stream with large mossy rocks in subtropical forest consisting of medium and large hardwood trees and shrubs. The air temperature when specimens were collected was 17–25 ° C and relative humidity was 80–90 %. Calls were not heard in any of the survey work. The breeding season is likely to encompass September and October and possibly longer as all males were observed with velvety nuptial pads lacking spines in both September and October and four of the six females collected in September were gravid. The single female collected in June was not gravid. The tadpole and breeding behaviour of this species is unknown. Other amphibian species found at the collection site in Ho Thau Commune were Bombina microdeladigitora Liu, Hu, Yang , Oreolalax sterlingae Nguyen, Phung, Le, Ziegler & Böhme , Leptobrachella sp. , Leptobrachium ailaonicum (Yang, Chen & Ma) , Nanorana yunnanensis (Anderson) , and Atympanophrys gigantica (Liu, Hu & Yang) on Mount Pu Ta Leng, Amolops minutus and Amolops spicalinea Nguyen, Tapley, La & Rowley on Mount Fansipan. On Mount Nam Kang Ho Tao this species is sympatric with A. minutus and Amolops daorum .

Conservation status.

This new species is currently known from between 1928–2784 m a. s. l. at three localities in Lao Cai and Lai Chau provinces, up to 48 km apart in the Hoang Lien Range (Mount Pu Ta Leng, Mount Fansipan and Mount Nam Kang Ho Tao). It was not detected in over a dozen field surveys along the Cat Cat River in Hoang Lien National Park ( 22.3214°N 103.8264°E, 1244 m a. s. l.) in evergreen forest indicating that it may not occur at lower elevation. The species’ estimated range is a narrow band of high-elevation habitat along the boundary of Lao Cai and Lai Chau provinces in Vietnam and into Yunnan Province in China. Its EOO is currently predicted to 2281 km 2 (Fig. 1 ). It occurs in a single threat defined location. The habitat of this species in all three localities is degraded, at elevations below 2000 m a. s. l., forest is being degraded in riparian habitat to establish cardamom plantations. On Mount Fansipan, the forest in which this species occurs is being negatively impacted by fuelwood collection for the tourism industry. A tourist camp is located just 500 m from the streams where this species was recorded on Mount Fansipan and effluent from the tourist camps is discharged into the stream. The habitat in higher elevations on Mount Fansipan is polluted with litter discarded by tourists and the gravel stream substrate has been intensively mined to line trekking routes, and this may have an impact on oviposition sites and larval development sites (see Nguyen et al. 2020 for details). Northern Vietnam is increasingly impacted by forest fires ( Le et al. 2014; Vadrevu et al. 2019) and forest fires also threaten the habitat of Amolops cuongi at high elevation sites with natural forest have a greater probability of fire in northern Vietnam ( Trang et al. 2022). Climate change is also a threat to the new species and a warmer climate could lead to a net loss in range (e. g., Duan et al. 2016). The fungal pathogen, Batrachochytrium dendrobatidis , was not detected from 30 samples collected from four different anuran amphibian species at approximately 2650 m a. s. l. on Mount Fansipan in September 2017; including four samples from Amolops cuongi , it was also not detected from 20 samples from eight different anuran amphibian species at approximately 2000 m a. s. l. on Mount Fansipan in June 2018, including four samples from Amolops cuongi ( Tapley et al. 2020; reported as Amolops sp. 1 ). Given the relatively small range, number of locations and ongoing habitat loss and modification, this species qualifies for being assessed as Vulnerable in accordance with the IUCN Red List of Threatened Species categories and criteria B 1 ab (iii) (see IUCN 2012).

Comparisons.

As molecular and morphological analyses confirm that the new species belongs to the A. mantzorum group, we compare the new species with other members of the A. mantzorum group: Amolops cuongi sp. nov. differs from A. ailao by the absence of a glandular dorsolateral fold (vs present in A. ailao ); a smaller ratio of TD / ED ( TD / ED 0.24–0.36 vs 0.52 in males; 0.26–0.35 vs 0.58 in females in A. ailao ); tibiotarsal articulation reaching to the nostril (vs tibiotarsal articulation reaching beyond anterior corner of eye in A. ailao ); the absence of brown mottling on the throat (vs present in A. ailao ); and granular ventral surface (vs smooth in A. ailao ) ( Tang et al. 2023); from A. dafangensis by having a smaller size in males ( SVL 33.9–36.9 mm vs 43.2–46.8 mm in A. dafangensis ), glandular dorsolateral folds absent (vs present in A. dafangensis ), and the absence of brown mottling on the throat (vs present in A. dafangensis ) ( Li et al. 2024); from A. granulosus by having a smaller size in females ( SVL 37.9–44.4 mm vs 51.9 mm in A. granulosus ), tympanum visible (vs invisible in A. granulosus ), and having a dorsal body colouration of dark brown with diffuse-edged blotches of bluish grey, copper and yellowish green or pale green and copper (vs brown with black spots in A. granulosus ) (Liu and Hu 1961; Fei et al. 2009, 2010); from A. jinjiangensis by having a smaller size ( SVL 33.9–36.9 mm vs 43.0–52.0 mm in males; 37.9–44.4 mm vs 58.0–65.0 mm in females in A. jinjiangensis ), tympanum visible (vs invisible in A. jinjiangensis ), and glandular dorsolateral folds absent (vs present in A. jinjiangensis ), and the absence of small granules on the tympanum (vs present in A. jinjiangensis ) (Yang et al. 1983; Yang 2008; Fei et al. 2009); from A. lifanensis by having a smaller size ( SVL 33.9–36.9 mm vs 52.0–56.0 mm in males; 37.9–44.4 mm vs 61.0–79.0 mm in females in A. lifanensis ), and tympanum distinct (vs invisible in A. lifanensis ) (Su et al. 1986; Fei et al. 2009); from A. loloensis by having a smaller size ( SVL 33.9–36.9 mm vs 54.5–62.0 mm in males; 37.9–44.4 mm vs 69.5–77.5 mm in females in A. loloensis ), tympanum distinct (vs invisible in A. loloensis ), dorsal colour pattern (dark brown with diffuse-edged blotches of bluish grey, copper, and yellowish green or pale green and copper vs dark green with many large brown spots in A. loloensis ), tibiotarsal articulation reaching to the nostril (vs tibiotarsal articulation reaching to the eye in A. loloensis ), head longer than wide (vs wider than long or long as wide in A. loloensis ), and relative finger lengths: I <II <IV <III (vs I = II <IV <III in A. loloensis ) (Liu 1950; Fei et al. 2009); from A. mantzorum by having a smaller size ( SVL 33.9–36.9 mm vs 48.8–57.0 mm in males, 37.9–44.4 mm vs 57.5–72.0 mm in females in A. mantzorum ), tympanum distinct (vs invisible in A. mantzorum ), and hind limbs with dark crossbars (vs without dark crossbars in A. mantzorum ) (Liu 1950; Fei et al. 2009, 2017); from A. minutus by having a smaller tympanum ( TD / ED 0.24–0.37 vs 0.38–0.41 in males; 0.26–0.35 vs 0.38–0.40 in females in A. minutus ), a larger disc of finger III ( FTD / ED 0.43–0.52 vs 0.29–0.33 in males, 0.46–0.67 vs 0.36–0.39 in females in A. minutus ; FTD / SVL 0.07–0.08 vs 0.04–0.05 in A. minutus ), a granular ventral surfaces and flanks (vs smooth in A. minutus ), the presence of a band of small spinules running from below nares, along upper lip, around lower half of eye, between tympanum and eye and rear axis of mandibles (vs spinules typically only present posterior of tympanum in A. minutus ), and the absence of dorsolateral glandular folds (vs present in A. minutus ) ( Orlov et al. 2007; Pham et al. 2019; Suppl. material 2: fig. S 2); from A. sangzhiensis by having a smaller size ( SVL 33.9–36.9 mm vs 40.3–40.9 mm in males, 37.9–44.4 mm vs 52.6–57.7 mm in females in A. sangzhiensis ), and tympanum smooth (vs covered in fine granules in A. sangzhiensis ) ( Qian et al. 2023); from A. shuichengicus by having a smaller size in females ( SVL 37.9–44.4 mm vs 48.5–55.5 mm in A. shuichengicus ), the absence of dorsolateral glandular folds (vs present in A. shuichengnicus ), and the absence of a cream maxillary gland (vs present in A. shuichengnicus ) ( Lyu et al. 2019); and from A. tuberodepressus by having a smaller size ( SVL 33.9–36.9 mm vs 44.0–57.0 mm in males; SVL 37.9–44.4 mm vs 61.0– 70 mm in A. tuberodepressus in females), tibiotarsal articulation reached to the nostril (vs tibiotarsal articulation reaching beyond tip of snout in A. tuberodepressus ), tympanum distinct (vs invisible in A. tuberodepressus ), and different dorsal colour pattern (green with some dark or pale green spots and irregular small black dots in A. tuberodepressus ) (Liu et al. 2000; Fei et al. 2009).

Figures

Figure 1. A. Map of the type localities of species in the Amolops mantzorum group; B. Zoomed in area showing the known localities and predicted distribution of Amolops cuongi sp. nov. Star indicates type locality of Amolops cuongi sp. nov. The precise type locality of A. lifanensis is not known (Lishan and Maoxian counties in central Sichuan Province).

Figure 2. Bayesian phylogeny based on 16 S, ND 2, and cyt b genes. Numbers on branches are BPP and UFB, respectively.

Figure 3. A. Dorsolateral view and; B. Ventral view of the male holotype (IEBR A. 5139) of Amolops cuongi sp. nov. in life.

Figure 4. A. Palmar aspect of right hand; B. Plantar aspect of right foot of the male holotype (IEBR A. 5139) of Amolops cuongi sp. nov.

Figure 5. Amolops cuongi sp. nov. in preservative, adult male paratype ILS H. 3665. A. Dorsal view; B. Ventral view; C. Lateral view; D. Palmar aspect of right hand; E. Plantar aspect of right foot. Scale bars 10 mm.

Figure 6. Dorsolateral view of Amolops cuongi sp. nov. in life. A. Adult male paratype ILS H. 3665; B. Adult female paratype ILS H. 3666; C. Adult male paratype ILS H. 3683; D. Adult female paratype ILS H. 3684; E. Adult female paratype ILS H. 3662; F. Subadult paratype HLNP 2017 1409 00030; G. Subadult paratype ILS H. 3663.