A new newt species, Hypselotriton huanggangensis sp. nov., is described based on nine specimens collected from Huanggangshan Mountains, Yanshan County, Jiangxi, China. Morphologically, the new species is characterized by the combination of nine external characters: (1) obvious black patches with clear boundaries on the whole body; (2) ground color of the dorsal body tan; (3) ground color of venter bright orange; (4) skin rough; (5) vertebral ridge weak; (6) fingers and toes overlapping when forelimb and hindlimb adpressed towards each other along body; (7) postocular orange spot absent; (8) small white warty glands around the eye; (9) two discontinuous longitudinal lines formed by white warty glands from neck to lateral parts of tail. Molecularly, the new species forms an independent clade with strong support in the phylogenetic trees of the genus based on the mitochondrial locus of NADH dehydrogenase subunit 2 (ND2) gene fragments. The new species distinctly differs from H. fudingensis by differences in its body measurements, vertebral ridge, dorsal black patches, and ventral black patches. Furthermore, the new species and H. fudingensis are geographically isolated by a series of high mountain ranges, including the Wuyishan and Jiufengshan Mountains. The number of Hypselotriton species is now 11.

Black patches, fire-bellied newts, geographical isolation, morphology, phylogenetics, taxonomy

The newt genus Hypselotriton Wolterstorff, 1934 (Urodela, Salamandridae) is distributed in China, including Anhui, Jiangsu, Zhejiang, Fujian, Jiangxi, Guangdong, Hubei, Henan, Hunan, Yunnan, and Guizhou Provinces (AmphibiaChina 2024; AmphibiaWeb 2024; Frost 2024). The generic classifications between Hypselotriton and Cynops has a lengthy history of taxonomic debate (Tschudi and Johann 1838; Wolterstorff 1934; Chang 1935; Zhao and Hu 1984; Zhao et al. 1988; Chan et al. 2001; Weisrock et al. 2006; Zhang et al. 2008; Dubois and Raffaëlli 2011, 2012; Raffaëlli 2013, 2022; Tominaga et al. 2013; Fei and Ye 2016). Previously, some arrangements suggested that Hypselotriton is a junior synonym of Cynops (Ye et al. 1993; Wu et al. 2010a; Fei and Ye 2016). However, recent phylogenetic studies have presented evidence that Cynops sensu lato (including Hypselotriton) is paraphyletic with respect to Pachytriton and Paramesotriton (Rancilhac et al. 2021; Zhong et al. 2021; Yuan et al. 2022). Following the latest taxonomic arrangements (Dubois and Raffaëlli 2009; Dubois et al. 2021; Frost 2024) and the premise of monophyly, the genus Cynops Tschudi, 1838 is restricted to the Japanese species and all Chinese species are placed in the genus Hypselotriton.

Currently, the following 10 species of Hypselotriton have been recorded: H. cyanurus Liu, Hu & Yang, 1962; H. yunnanensis Yang, 1983; H. chenggongensis Kou & Xing, 1983; H. wolterstorffi Boulenger, 1905; H. orientalis David, 1873; H. orphicus Risch, 1983; H. fudingensis Wu, Wang, Jiang & Hanken, 2010; H. maguae Lyu, Qi & Wang, 2023; H. jiaoren Lyu, Qi & Wang, 2023; H. glaucus Yuan, Jiang, Ding, Zhang & Che, 2013. Recent studies suggest that overall species richness of Hypselotriton is underestimated (Yuan et al. 2022; Lyu et al. 2023). The reevaluations of the “widespread” species (H. orientalis and H. yunnanensis) and the survey of unexplored areas are likely to reveal overlooked diversity.

Huanggangshan Mountains (about 10 km long) is located on the northwestern side of the Wuyishan Mountains (about 550 km long), China. The highest peak (2161 m a.s.l) of Huanggangshan Mountains is known as the “roof of Eastern Mainland China” and “the first peak in the southeast of the mainland” (Lin and Ye 1985). During the recent surveys, on the northwestern side of the Huanggangshan Mountains, nine fire-bellied newts of unidentified Hypselotriton population were sampled in a small waterhole. After examination, they were found to differ from other congeneric members in both morphological and molecular characteristics. As a result, we herein describe it as a new species of Hypselotriton.

Morphologically, our newly collected specimens can be distinguished from all known congeners (details in the taxonomic account below), which can be reliably identified by the obvious black patches with clear boundaries on the whole body and weak vertebral ridge. Statistical analyses on the morphometric measurements were performed on the specimens from northeastern Jiangxi and its sister species H. fudingensis from northeastern Fujian (Table 2). The results of T-test on morphometrics showed that individuals of the northeastern Jiangxi population and H. fudingensis are obviously different in HL, ED, and IND for males (p-values < 0.05), and in TAD for females (p-values < 0.05). Furthermore, once differences attributable to SVL were accounted for (Table 4), there were significant differences between H. huanggangensis sp. nov. and H. fudingensis for TAD, HL, ED, and AG in males, and significant differences for TOL, TAD, HL, HW, AG, FLL and HLL in females.

BI and ML analyses resulted in similar identical topologies (Fig. 2). As shown in the tree (Fig. 2), three major clades with strong support were revealed for the samples of Hypselotriton, while the relationship among these clades are not resolved. The first clade is composed of samples of H. cyanurus (BPP 1.00, BS 100) and H. yunnanensis (BPP 1.00, BS 97). The second clade consists of H. glaucus from eastern Guangdong (BPP 1.00, BS 100) and H. jiaoren from northern Guangdong (BPP 1.00, BS 100). In the third clade, the new specimens from northeastern Jiangxi form a distinct lineage (BPP 1.00, BS 100), which is sister to H. fudingensis with support values (BPP 1.00, BS 99). The genetic distances based on the ND2 gene among species of Hypselotriton are presented in Table 3. The putative new species from Huanggangshan Mountains showed obvious genetic divergence from other congeners. When compared with closely related recognized congeners, the minimum uncorrected genetic distance was 2.2% between the clade from Huanggangshan Mountains and H. fudingensis (Table 3).

Figure 2. 

Bayesian-inference tree and maximum-likelihood phylogenies based on mitochondrial ND2 gene. Bayesian posterior probabilities and the bootstrap supports (BPP/BS) are shown near the notes. Number at the ends of the lineages correspond to the IDs in Table 1.

Accordingly, combining the results of the morphological examination presented below and the phylogenetic analysis, the specimens from northeastern Jiangxi are regarded as a new species that is described herein.

Taxonomic account

 Hypselotriton huanggangensis Jiang, Huang, Fan, Cheng, Raffaëlli & Chen, sp. nov.

https://zoobank.org/18334E5C-BED9-47AE-A42D-FA916E7B2CC2

Figs 3, 4, 5

Type material

Holotype. HSA 23097, adult male from Huanggangshan Mountains (28.72°N, 117.33°E; elevation 84 m), Yanshan County, Shangrao City, Jiangxi Province, China, collected by Zhihao JIANG on 22 July 2023.

Figure 3. 

Paratypes of Hypselotriton huanggangensis sp. nov. (HSA23075) A dorsalateral view in life B ventral view in life C small waterhole around mountain shrubs without direct sunlight at the type locality.

Paratypes. Six adult males: HSA23075–23076, HSA23098–23099, HSA23102–23103, and two adult females: HSA23100–23101. Same collection date and locality as the holotype.

Etymology

The specific name huanggangensis refers to the type locality in the Huanggangshan Mountains. For the English common name, we suggest “Huanggangshan Fire-bellied Newt” and for the Chinese name, 黄岗山蝾螈 (huáng gǎng shān róng yuán).

Diagnosis

(1) Small body size, TOL 73.0–79.1 mm in adult males, TOL 79.6–89.4 mm in adult females; (2) obvious black patches with clear boundaries on the whole body; (3) ground color of the dorsal body tan; (4) skin rough; (5) ground color of venter bright orange; (6) vertebral ridge weak; (7) fingers and toes overlapping when forelimb and hindlimb adpressed towards each other along body; (8) parotoid gland inconspicuous; (9) postocular orange spot absent; (10) white warty glands around the eye; (11) two discontinuous longitudinal lines which consist of white warty glands from neck to lateral parts of tail (Fig. 6).

Description of the holotype

HSA 23097 (Figs 4, 5), adult male with a small, slender body (TOL 79.1 mm, SVL 47.3 mm). Head oval in dorsal view; snout truncate, projecting slightly beyond mandible; nostril small but conspicuous; tongue elongate, enlarged anteriorly, with free lateral margin; vomerine tooth patch ∧–shaped; parotoid gland inconspicuous, gill remnants absent; gular fold present; skin with fine granules, covering most parts of dorsum, venter, chin and tail; vertebral ridge weak; cloacal opening oval, slightly protruding; limbs slender, fingers and toes overlapping when forelimb and hindlimb adpressed towards each other along the body; four fingers and five toes, slender and elongated, lacking webbing; relative length of fingers I < IV < II < III; relative length of toes I < V < II < IV < III. Tail laterally compressed, tapers posteriorly; caudal fin distinct; tail tip bluntly pointed.

Figure 4. 

Comparison of holotype of Hypselotriton huanggangensis sp. nov. (left, HSA23097) and Hypselotriton fudingensis (right, HSA23108) in life A dorsal view B ventral view, 1, 5 obvious black patches, 2 weak vertebral ridge, 3 small spots, 4 conspicuous vertebral ridge, 6 bright orange venter without dark blotches.

Figure 5. 

Comparison of holotype of Hypselotriton huanggangensis sp. nov. (left, HSA23097) and Hypselotriton fudingensis (right, HSA23104) in preservative A dorsal views B ventral views, 1–6 same as in Fig. 4.

Figure 6. 

Two discontinuous longitudinal lines which consist of white warty glands from neck to lateral parts of tail (Hypselotriton huanggangensis sp. nov., HSA23099) in life.

Coloration of the holotype

In life, obvious black patches with clear boundaries on the whole body; ground color of the dorsal body tan; ground color of venter bright orange; white warty glands from the lateral part of head to tail; axilla, cloacal opening, and venter of tail bright orange. In preservative after six months (Fig. 5), dorsum, flanks, and limbs slightly darker. All orange coloration of venter fades to creamy white.

Table 4.

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Test for differences between H. huanggangensis sp. nov. and H. fudingensis using ANCOVA (SVL as covariate).

Variable	Males	Females
Total length (TOL)
F	6.78	12.17
P	0.052	0.008
Tail length (TAL)
F	1.09	2.27
P	0.419	0.185
Maximum tail depth (TAD)
F	12.34	15.48
P	0.019	0.004
Head length (HL)
F	8.76	9.66
P	0.035	0.013
Maximum head width (HW)
F	3.77	16.71
P	O.120	0.004
Snout length (SL)
F	1.18	1.23
P	0.395	0.357
Eye diameter (ED)
F	12.00	1.91
P	0.020	0.228
Interorbital distance (IOD)
F	1.20	1.48
P	0.390	0.301
Eye–nostril length (EN)
F	0.03	0.38
P	0.967	0.700
Internasal distance (IND)
F	5.91	0.189
P	0.064	0.833
Axilla–groin length (AG)
F	76.89	9.38
P	0.010	0.014
Forelimb length (FLL)
F	0.07	8.86
P	0.938	0.016
Hindlimb length (HLL)
F	1.48	5.65
P	0.330	0.042

Variation

Linear measurements are summarized in Table 2. Females (TOL 79.6–89.4 mm) are distinctly larger than males (TOL 73.0–79.1 mm). All paratypes resemble the holotype except that the cloaca is wider and more swollen in males than in females, the irregular bright-orange patches on ventral surface occupy more surface in females than in males, and the gular fold absent in some individuals.

Comparisons

Hypselotriton huanggangensis sp. nov. is phylogenetically close to H. fudingensis, which is distributed in northeastern Fujian. However, H. huanggangensis sp. nov. differs from H. fudingensis by its weak vertebral ridge (vs vertebral ridge conspicuous), dorsal black patches (vs small or no spots on dorsum), and ventral black patches (vs venter bright orange without dark blotches).

In addition, H. huanggangensis sp. nov. further differs from the remaining congeners.

Hypselotriton huanggangensis sp. nov. differs from H. orphicus by its weak vertebral ridge (vs slightly bulged) and obvious black patches with clear boundaries on the whole body (vs small or moderate dorsal blackish dots in H. orphicus).

Hypselotriton huanggangensis sp. nov. differs from H. orientalis by its parotoid gland inconspicuous (vs conspicuous) and the presence of obvious black patches with clear boundaries on the dorsum (vs absent in H. orientalis).

Hypselotriton huanggangensis sp. nov. differs from H. glaucus by its obvious black patches with clear boundaries on the whole body (vs dorsum, flanks, limbs, and upper side of tail with irregular obscure greyish blue patches in H. glaucus).

Hypselotriton huanggangensis sp. nov. differs from H. jiaoren by its rough skin (vs smooth), and obvious black patches with clear boundaries on the whole body (vs dorsum, flanks, limbs, and upper side of tail uniformly dark brown in H. jiaoren).

Hypselotriton huanggangensis sp. nov. differs from H. maguae by having its fingers and toes overlapping when forelimbs and hindlimbs are adpressed (vs forelimbs and hindlimbs not meeting when adpressed towards each other along body), and obvious black patches with clear boundaries on the whole body (vs dorsum, flanks, limbs, and upper side of tail uniformly dark brown in H. maguae).

Hypselotriton huanggangensis sp. nov. can be distinctly distinguished from H. wolterstorffi, H. cyanurus, H. chenggongensis and H. yunnanensis by its absent postocular orange spot (vs present).

Distribution and habitat

Hypselotriton huanggangensis sp. nov. is currently known only from the type locality on the western side of the Wuyishan Mountains in northeastern Jiangxi. Newts were found in a small waterhole around mountain shrubs without direct sunlight, at 84 m a.s.l. All individuals were observed in July, September, and February.

Despite more than a century of effort, taxonomists have yet to reach a consensus on the concept of species and methods of all species delimitation (Mayden 1997; de Queiroz 1998; Fu and Zeng 2008; Yang and Rannala 2010; Chen et al. 2013; Peng et al. 2014). Trying to solve “the notorious problem of taxonomic uncertainty (Uetz et al. 2024)”, Huang et al. (2021) proposed the principle of “species subdivision” with recommendable “subdivision” at the species level. It should help to understand species natural history more effectively and facilitate consistent actions in taxonomy and practices of conservation biology.

In the present study, although the genetic distance based on the ND2 gene fragment between H. huanggangensis sp. nov. and its sister species H. fudingensis is not very large (uncorrected p-distance = 2.2%), morphological differences between them are distinct (Fig. 4; Table 2). In addition, H. huanggangensis sp. nov. and H. fudingensis are isolated by a series of high mountain ranges, including the Wuyishan and Jiufengshan Mountains. These barriers often isolate different amphibian species (Chen et al. 2020).

With the addition of the new species described here, the genus Hypselotriton now includes 11 species. Until now, seven species of Hypselotriton were found in the southeastern Chinese hilly area (H. huanggangensis, H. jiaoren, H. glaucus, H. maguae, H. orphicus, H. fudingensis and H. orientalis), and another four species of Hypselotriton are distributed in southwestern China. Due to unresolved relationships, a more extensive sampling of taxa and molecular data are necessary for reliable conclusions on the evolution and taxonomy of Hypselotriton.

We thank Cong Liu for assistance in the field. We also thank Ben Liu for discussion of the analysis of phylogenetic data.