The fire-bellied newt genus Hypselotriton Wolterstorff, 1934, belongs to the family Salamandridae and is restricted to southern China (AmphibiaChina 2025). For the past forty years, the distinction between the genera Cynops Tschudi, 1838, and Hypselotriton has been the subject of an ongoing controversy (Zhao and Hu 1984; Zhao et al. 1988; Chan et al. 2001; Weisrock et al. 2006; Zhang et al. 2008; Dubois and Raffaëlli 2011; Raffaëlli 2013; Fei and Ye 2016; Hernandez 2018; Raffaëlli 2022). Recent phylogenetic studies suggest that the species of Hypselotriton from the Chinese mainland are monophyletic, whereas Cynops in its former configuration was paraphyletic with respect to Pachytriton and Paramesotriton (Yuan et al. 2022; Jiang et al. 2024; Wang et al. 2024). In this work, we adopt Hypselotriton at the generic level following the latest taxonomic arrangements (AmphibiaChina 2025; Frost 2025).

The genus Hypselotriton was erected by Wolterstorff (1934) for the species H. wolterstorffi (Boulenger, 1905). Within this genus, Zhao and Hu (1984) and Zhao et al. (1988) recognized two species-groups, and Dubois and Raffaëlli (2009, 2011) classified them into two subgenera. The nominotypical subgenus is Hypselotriton, which includes Hypselotriton (H.) chenggongensis (Kou & Xing, 1983), H. (H.) cyanurus (Liu, Hu & Yang, 1962), and H. (H.) wolterstorffi (Boulenger, 1905). The second subgenus is Cynotriton, which includes Hypselotriton (C.) fudingensis (Wu, Wang, Jiang & Hanken, 2010), H. (C.) orientalis (David, 1873), and H. (C.) orphicus (Risch, 1983). Yuan et al. (2013) described H. glaucus (Yuan, Jiang, Ding, Zhang & Che, 2013) from Guangdong as a new species based on morphological and molecular characters. Rao (2022) described H. puerensis (Rao, 2022) from Yunnan as a new species based on morphological characters. Lyu et al. (2023) described H. jiaoren (Lyu, Qi & Wang, 2023) and H. maguae (Lyu, Qi & Wang, 2023) as new species based on morphological and molecular characters; meanwhile, they elevated the subspecies H. cyanurus yunnanensis (Yang, 1983) to species rank and synonymized H. puerensis with H. yunnanensis. Jiang et al. (2024) described H. huanggangensis Jiang, Huang, Fan, Cheng, Raffaëlli & Chen, 2024 as a new species based on morphological and molecular characters. Wang et al. (2024) erected a new subgenus Hakkatriton, which included Hypselotriton (H.) orphicus and H. (H.) jiaoren, and described H. oolong Wang, Zeng, Wei & Lyu, 2024 as a new species based on morphological and molecular characters; meanwhile, they synonymized H. glaucus with H. orphicus. Currently, the following 11 species have been recorded: Hypselotriton wolterstorffi, H. orientalis, H. orphicus, H. chenggongensis, H. cyanurus, H. fudingensis, H. huanggangensis, H. jiaoren, H. maguae, H. oolong and H. yunnanensis.

The Oriental fire-bellied newt Hypselotriton orientalis (David, 1873) sensu lato is widely distributed in China, including Anhui, Jiangsu, Zhejiang, Fujian, Jiangxi, Hubei, Henan, and Hunan provinces (Fei and Ye 2016). Fei et al. (2012) described a new subspecies, H. orientalis qianshan, which is distributed in Anhui, Henan, and Hubei provinces, based on its smaller body size, smoother skin, weaker vertebral ridge, and thinner ventral fin fold compared to the nominate subspecies. At the molecular level, few phylogenetic studies have been conducted on H. orientalis sensu lato due to limited samples, and the phylogenetic relationships within the species remain unresolved (Wu et al. 2010a; Yuan et al. 2022). In this work, we elevate Hypselotriton orientalis qianshan to the rank of a distinct species based on molecular and morphological data.

Color-pattern polymorphism among many species has played an important role in evolution and ecology, and sometimes this polymorphism is taxon-specific (Giery et al. 2020; Smith et al. 2024). The genus Hypselotriton has several polymorphic species, but only a few have been studied (Fei et al. 2006; AmphibiaChina 2025). For decades, the description of H. orientalis sensu lato has been incomplete, often causing confusion in taxonomic morphological comparisons. In this work, we described the different color patterns of H. orientalis sensu lato.

Morphologically, this newly ranked taxon distinctly differs from Hypselotriton orientalis orientalis by its rust-red or rust-white patches on the dorsum, discontinuous dorsal ridge lines, orange-red patches on finger I, black stripes on the venter of the neck, absent or discontinuous, and a relatively inconspicuous vertebral ridge (Figs 3, 4, 5, 6). Statistical analyses on the morphometric measurements (14 measurements) were performed using the specimens of H. qianshan stat. nov. and H. orientalis orientalis (Tables 2, 3). The results of linear measurements and Univariate Analysis of Covariance (ANCOVA) with SVL as the covariate show that the newly ranked taxon has a smaller body length ratio (TOL/SVL and TAL/SVL), smaller fore-limb length ratio (FLL/SVL), longer internasal distance in males, and longer interorbital distance in females. Descriptions of color-pattern polymorphism show that H. orientalis sensu lato has significant polymorphisms at the intraspecific level (details in Taxonomic account below).

Molecularly, BI and ML analyses resulted in similar topologies (Fig. 2). Within the subgenus Cynotriton, two major clades were revealed in samples of Hypselotriton orientalis sensu lato. The newly ranked taxon forms an independent clade with strong support (1.00/99). BPP and BS of the other clade (H. orientalis orientalis) are weak. The uncorrected group mean genetic distance between H. qianshan stat. nov. and H. orientalis orientalis was 3.5%. As shown in the tree, the Hunan population and the Dabie Mountain populations form a monophyletic group.

Accordingly, based on the results of the morphological examination presented below and the phylogenetic analysis, the specimens from the Dabie Mountains and Hunan Province are redescribed and elevated to species rank.

The indefinite nature of many species boundaries has long been recognized (Burbrink et al. 2022). In this study, we elevate the subspecies Hypselotriton orientalis qianshan to a distinct-species status as H. qianshan stat. nov. based on morphological characters, phylogenetic evidence, and geographic separation, following the phylogenetic species concept and considering geographic separation an important factor in the process of speciation.

Previous biogeographic studies have shown that Hypselotriton qianshan stat. nov. and H. orientalis orientalis are predominantly isolated by the Yangtze River (Fei et al. 2012; Fei and Ye 2016). However, our phylogenetic results showed that the Hunan population and other populations north of the Yangtze River form a monophyletic group. Hypselotriton orientalis sensu lato was estimated to have diverged around the Pleistocene (Yuan et al. 2022). During that time, the Twain-Hu Plain was a flood plain composed of inter-river depressions (Li et al. 2001; Hu et al. 2010). Hypselotriton qianshan stat. nov. may have spread across the Twain-Hu Plain through numerous marshes, which is consistent with the phylogenetic results.

A combination of two or more characters (shorter trunk ratio, orange-red patches on finger I and black stripes on the venter of the neck, absent or discontinuous) can effectively distinguish Hypselotriton qianshan stat. nov. from H. orientalis orientalis (Fig. 5). Meanwhile, in the populations of H. orientalis orientalis, rough skin and conspicuous vertebral ridges are often found in northern Zhejiang and Jiangsu Province. In the populations of H. qianshan stat. nov., rust-red or rust-white patches on the dorsum and discontinuous dorsal ridge lines are often found in the western Dabie Mountains.

The Dabie Mountains are located in the transition zone between the Palearctic and Oriental realms, and have a high biological diversity. Several new species of amphibians have been discovered in the Dabie Mountains region in recent years, such as Microhyla dabieshanensis Zhang, Chen & Zhang, 2022, Rana dabieshanensis Wang, Qian, Zhang, Guo, Pan, Wu, Wang & Zhang, 2017, Zhangixalus zhoukaiyae (Pan, Zhang & Zhang, 2017) and Tylototriton anhuiensis Qian, Sun, Li, Guo, Pan, Kang, Wang, Jiang, Wu & Zhang, 2017 (Wang et al. 2017; Pan et al. 2017; Qian et al. 2017; Zhang et al. 2022). The newly ranked taxon Hypselotriton qianshan stat. nov. is also predominantly distributed in this region, where the potential species richness deserves further attention.

The potential drivers of color-pattern polymorphisms in Hypselotriton orientalis sensu lato remain unresolved. Notably, during captivity, some individuals developed slightly rougher skin after being transferred to a terrestrial environment, while others exhibited changes in dorsal coloration in response to different feeding conditions. These observations suggest that H. orientalis sensu lato exhibits phenotypic plasticity (Barzaghi et al. 2022). Further study is needed to elucidate the specific drivers of this color-pattern polymorphism.