A new species of Chinese horned toad (Anura, Megophryidae, Boulenophrys) from western Guangdong Province, China, with recommendations for extinction risk assessments for several related congeners

A new species of Chinese horned toad (Anura, Megophryidae, Boulenophrys) from western Guangdong Province, China, with recommendations for extinction risk assessments for several related congeners Yi-Yang Zhao1*, Shi-Shi Lin2*, Yuan-Hang Li2, Zhi-Tong Lyu3, Ke Zheng4, Zhao-Chi Zeng2, Amaël Borzée5, Jian Wang2 1 Guangdong Wildlife Monitoring Rescue and Conservation Center, Guangzhou 510520, Guangdong, China 2 Guangdong Polytechnic of Environmental Protection Engineering, Foshan 528216, Guangdong, China 3 Mountain Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610213, Sichuan, China 4 GuangdongYangchunEhuangzhangProvincialNatureReserveManagementOffice,Yangjiang529631,Guangdong,China 5 LaboratoryofAnimalBehaviourandConservation,CollegeofLifeSciences,NanjingForestryUniversity,Nanjing210037,Jiangsu,China https://zoobank.org/1888DFB8-1A61-45E4-8C8A-BD607671E666 Corresponding authors: Jian Wang ([email protected]); Amaël Borzée ([email protected]); Zhao-Chi Zeng ([email protected]) * These authors contributed equally to this work. Academic editor: Günter Gollmann ♦ Received 9 September 2025 ♦ Accepted 17 November 2025 ♦ Published 24 November 2025 Abstract The genus Boulenophrys is predominantly distributed in China and exhibits high species diversity. However, accurate conservation assessments for this genus are hindered by its unresolved taxonomy, which is linked to morphological conservatism, sympatric distribution patterns, and limited field survey data. In this study, we describe a new species, namely Boulenophrys yangchunensis sp. nov., and report new locality records for B. acuta (Wang, Li & Jin, 2014) and B. yunkaiensis Qi, Wang, Lyu & Wang, 2021 from western Guangdong Province, China. Additionally, we propose downlisting B. acuta, currently listed as Critically Endangered (CR) on the IUCN Red List of Threatened Species, to a lower threat category, and we recommend an extinction risk category update for Boulenophrys yangchunensis sp. nov., B. yunkaiensis, and B. gaolanensis Song, Wang, Qi, Wang & Wang, 2024. We further discuss key conservation challenges and provide targeted management recommendations to address these challenges. Key Words conservation assessment, management suggestions, molecular phylogeny, morphological conservatism, range extension, reassessment, sympatry, systematics Introduction The speciose genus Boulenophrys Fei, Ye & Jiang, 2016, known as the Chinese horned toads and currently comprising 78 recognized species, is widespread in the subtropical and tropical areas of mainland East Asia (Frost 2025). Specifically, the genus is principally distributed in southern China and southwards into northernmost Vietnam, Laos, Myanmar, and Thailand (Fei and Ye 2016; Lyu et al. 2023; Frost 2025). Boulenophrys possess limited dispersal abilities and narrow ecological niches, resulting in restricted distribution ranges for many species Herpetozoa 38: 345–357 (2025) DOI 10.3897/herpetozoa.38.e171400 Copyright Yi-Yang Zhao et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. herpetozoa.pensoft.net Yi-Yang Zhao et al.: A new species of Boulenophrys346 (Wang et al. 2019a; Lyu et al. 2023). Due to the combined effect of various factors, conservation efforts for this genus have encountered significant challenges. Besides, their high levels of morphological conservatism and the lack of follow-up surveys have led to inadequate protection due to misidentifications and missing data (Lin et al. 2024). Therefore, accurate assessments of the extinction risk for Boulenophrys species still require a significant amount of field surveys and continuous data updates. As the research progressed, Guangdong Province, China, gradually became one of the provinces with extremely high diversity of the genus Boulenophrys (20 of 77 species). Currently, the type locality of 15 species is located within the jurisdiction of Guangdong Province, i.e., B. acuta (Wang, Li & Jin, 2014), B. dongguanensis (Wang & Wang, 2019), B. elongata Zeng, Wang, Chen, Xiao, Zhan, Li & Lin, 2024, B. fengshunensis Wang, Zeng, Lyu & Wang, 2022, B. gaolanensis Song, Wang, Qi, Wang & Wang, 2024, B. hungtai Wang, Zeng, Lyu, Xiao & Wang, 2022, B. insularis (Wang, Liu, Lyu, Zeng & Wang, 2017), B. nankunensis (Wang, Zeng & Wang, 2019), B. nanlingensis (Lyu, Wang, Liu & Wang, 2019), B. obesa (Wang, Li & Zhao, 2014), B. pepe Wang & Zeng, 2024, B. puningensis Wang, Zeng, Lyu, Xiao & Wang, 2022, B. shimentaina (Lyu, Liu & Wang, 2020), B. yingdeensis Qi, Lyu, Wang & Wang, 2021, and B. yunkaiensis Qi, Wang, Lyu & Wang, 2021 (Lyu et al. 2023; Song et al. 2024; Frost 2025). Among them, the Fengkai horned toad, Boulenophrys acuta, was most recently assessed for the IUCN Red List of Threatened Species in 2019 and listed as Critically Endangered (CR) under criteria B1ab(iii), due to its limited distribution range within Heishiding Nature Reserve in Fengkai County, western Guangdong Province, China (Li et al. 2014). Based on molecular data, Song et al. (2024) provided a range extension by reporting a new population from Mt. Yunkai in Xinyi City, western Guangdong Province, China, approximately 155 km away in straight-line distance. During our field surveys in Ehuangzhang NR in Yangchun City, western Guangdong Province, China, we collected a series of sympatric tadpole samples and adult specimens of the genus Boulenophrys (Fig. 1). Subsequent molecular analysis revealed that two of the samples (GEP asp062 and GEP asp064; Environmental Protection Engineering for the abbreviation GEP and amphibian tissue sample for the abbreviation asp) clustered with the typical lineage of B. acuta with shallow genetic divergence, and four samples (GEP asp061, GEP asp063, and GEP asp065–066) clustered with the typical lineage of B. yunkaiensis with shallow genetic divergence. These clusters represent new geographical subpopulations of the two species, respectively (Fig. 2). Additionally, five specimens (GEP a168–170, SYS a009518, and CIB 121751; Chengdu Figure 1. Map showing the type locality of Boulenophrys yangchunensis sp. nov. and the new distribution sites of B. acuta and B. yunkaiensis (1); the type locality of B. acuta (2); the type locality of B. gaolanensis (3); and the type locality of B. yunkaiensis and the new distribution site of B. acuta (4). Herpetozoa 38: 345–357 (2025) herpetozoa.pensoft.net 347 Institute of Biology, Chinese Academy of Sciences for the abbreviation CIB) exhibited distinct morphological differences and significant genetic divergence from all known congeners within the genus. Therefore, we describe a new species from Ehuangzhang NR, report range extensions for B. acuta (approximately 188 km in straight-line distance from its type locality in Heishiding NR) and for B. yunkaiensis (approximately 52 km from its type locality in Mt. Yunkai), and also provide a reassessment of the endangered status of B. acuta and assessments of B. yunkaiensis and B. gaolanensis. Materials and methods Morphology Five adult male specimens (GEP a168–170; CIB 121751; SYS a009518) of the genus Boulenophrys were collected on 11 August 2023 from Guangdong Yangchun Ehuangzhang Provincial Nature Reserve (21.851912°N, 111.421553°E; ca. 1,060 m a.s.l.) in Yangchun City, Guangdong Province, China. All examined specimens were fixed in 10% buffered formalin and later transferred to 70% ethanol. All studied specimens have been deposited at the Guangdong Polytechnic of Environmental Protection Engineering (GEP) facility in Foshan, Guangdong Province; the Museum of Biology, Sun Yat-sen University in Guangzhou, Guangdong Province, China (SYS); and the Herpetological Museum at the Chengdu Institute of Biology, Chinese Academy of Sciences (CIB) in Chengdu, Sichuan Province, China. External measurements were recorded with a digital caliper (Neiko 01407A stainless steel 6-inch digital caliper) to the nearest 0.1 mm. These measurements are as follows: SVL (snout–vent length, from tip of snout to posterior margin of vent); HDL (head length, from tip of snout to the articulation of the jaw); HDW (head width, head width at the commissure of the jaws); SNT (snout length, from tip of snout to the anterior corner of the eye); IND (internasal distance, distance between nares); IOD (interorbital distance, minimum distance between Figure 2. Maximum likelihood tree results from partial DNA sequences of the mitochondrial 16S rRNA and COI gene. Numbers before slashes indicate bootstrap support (BS), and numbers after slashes indicate Bayesian posterior probabilities (BPP). B. yunkaiensis B. gaolanensis B. yangchunensis sp. nov. B. acuta 0.05 B. shunhuangensis B. xianjuensis GEP asp061 ˙ B. boegeri B. palpebralespinosa B. minor B. lichun GEP asp066 ˙ B. daiyunensis B. baolongensis B. nanlingensis B. baishanzuensis B. cheni SYS a002278 ˚ B. fansipanensis B. yingdeensis GEP asp064 ˙ B. binlingensis B. daweimons B. yaoshanensis B. fengshunensis B. insularis B. dalaolingensis SYS a009518 ˙ SYS a009225 ˜ B. elongata SYS a004694 ˜ B. jinggangensis B. tongboensis B. jiulianensis X. mangshanensis GEP asp065 ˙ B. changyangensis B. qianbeiensis B. jiangi B. tuberogranulata B. liboensis B. angka B. anlongensis B. mirabilis B. congjiangensis SYS a009113 ˜ B. jingdongensis B. caudoprocta B. mufumontana B. hengshanensis B. dupanglingensis B. binchuanensis GEP asp062 ˙ SYS a002276 ˚ GEP a169 ˙ SYS a002266 ˚ SYS a009236 ˜ B. spinata B. fanjingmons B. hoanglienensis SYS a009235 ˜ B. xuefengmons B. sanmingensis B. leishanensis B. lini B. wushanensis B. kuatunensis B. rubrimera B. wugongensis B. brachykolos B. ombrophila B. daoji B. obesa B. chishuiensis GEP a170 ˙ B. caobangensis B. xiangnanensis B. hungtai B. lushuiensis B. daxuemons B. dongguanensis B. shimentaina B. huangniushiensis B. gutu B. omeimons B. sangzhiensis B. wuliangshanensis X. glandulosa B. puningensis B. yangmingensis B. nankunensis CIB 121751 ˙ B. pepe GEP a168 ˙ GEP asp063 ˙ B. lishuiensis B. frigida ʒEhuangzhang Nature Reserve, Yangchun ʓHeishiding Nature Reserve, Fengkai ʔGaolan Island, Zhuhai ʕMt Yunkai, Xinyi BS≥70 & BPP≥0.90 BS≥70 & BPP<0.90 BS<70 & BPP≥0.90 BS<70 & BPP<0.90 Boulenophrys Xenophrys 100/1.00 100/1.00 91/1.00 95/1.00 72/0.95 96/0.99 herpetozoa.pensoft.net Yi-Yang Zhao et al.: A new species of Boulenophrys348 upper eyelids); ED (eye diameter, from the anterior corner of the eye to the posterior corner of the eye); TD (tympanum diameter, horizontal diameter of tympanum); TED (tympanum–eye distance, from anterior edge of tympanum to posterior corner of the eye); HND (hand length, from the proximal border of the outer palmar tubercle to the tip of digit III); RAD (forearm or radioulna length, from the flexed elbow to the proximal border of the outer palmar tubercle); FTL (foot length, from distal end of shank to the tip of digit IV); TIB (crus or tibiofibula length, from the outer surface of the flexed knee to the heel). Sex was determined by external secondary sexual characters, such as the presence of vocal sacs, nuptial pads, or spines in males and their absence in females (Fei et al. 2009). Morphological characters of all recognized species of the genus Boulenophrys used for comparisons were based on an examination of museum specimens listed in Appendix I and information available in the literature (Table 1). Phylogeny Five tissue samples were derived from the five adult specimens (GEP a168–170; CIB 121751; SYS a009518). Another six tissue samples (GEP asp061– 066) were derived from the tail fins of different tadpoles from Guangdong Yangchun Ehuangzhang Provincial Nature Reserve (21.851912°N, 111.421553°E; ca. 1,060 m a.s.l.), and the tadpoles were not collected. In total, 94 samples were used for the phylogenetic analyses, encompassing 11 newly sequenced individuals and others downloaded from GenBank (https://www.ncbi. nlm.nih.gov/genbank/). Two samples of the genus Xenophrys Günther, 1864, were used as outgroups (Suppl. material 1). Two partial mitochondrial genes, the 16S ribosomal RNA (16S) and the cytochrome c oxidase 1 (COI), were used for phylogenetic analysis. DNA extraction, PCR amplification, and sequencing protocols followed Liu et al. (2018). We used Clustal X 2.0 (Thompson et al. 1997) to align the sequences using default parameters. We then used PartitionFinder (Lanfear et al. 2012) to determine the optimal partitioning schemes, and we determined that partitioning by gene was optimal for 16S, while partitioning by codon position was optimal for COI, with GTR+I+G identified as the best-fit nucleotide substitution model for all partitions. We constructed the phylogenetic trees using maximum likelihood (ML) implemented in RAxMLGUI v.1.3 (Silvestro and Michalak 2012) and Bayesian inference (BI) using MrBayes v.3.2.4 (Ronquist et al. 2012). For the ML analysis, an optimal tree was obtained, and branch supports were evaluated with 1000 rapid bootstrapping replicates. For the BI analysis, two independent runs were conducted, each running for 10,000,000 generations and sampled every 1000 generations, with the first 25% of samples discarded as burn-in, resulting in a potential scale reduction factor (PSRF) of < 0.01. Then, the remaining trees were used to create a consensus tree. Nodes having ML bootstrap values (BS) ≥ 70 and BI posterior probabilities (BPP) ≥ 0.90 were considered well supported. Genetic distances among all Boulenophrys samples were calculated in MEGA 11 using the uncorrected p-distance model based on the 16S. Threat assessments Among the focal species in this work, B. acuta has been assessed as Critically Endangered (ASG 2021), but B. yunkaiensis and B. gaolanensis have not been assessed. Here, the threat assessment of B. gaolanensis is relevant, as it is closely related to the taxa described in this manuscript. The geographic area of this study is characterized by low-elevation hills and mountains interrupted by low-elevation agricultural plains and large urban areas. As a result, the populations are disconnected both because of the landscape and human activities. To suggest an extinction risk assessment for these four species, we followed the IUCN Red List categories and criteria (www.iucnredlist.org/resources/redlistguidelines) due to their robustness, especially for species with restricted ranges (Maes et al. 2015), and because evaluations are conducted against quantitative thresholds for five criteria (IUCN 2012). However, we could not use criteria A (population size reduction), C (small and declining population size), and E (quantitative analysis of extinction risk) due to the absence of data on population sizes. Instead, we relied on criteria B (geographic range size) and D (very small population and/or restricted distribution) for the assessments. To determine the extent of occurrence (hereafter EOO) and the area of occupancy (hereafter AOO) for each species, we used the online platform GeoCAT (www.geocat.iucnredlist.org). Results Molecular phylogenetic analysis The BI and ML phylogenetic trees resulted in essentially identical topologies (ML phylogenetic topology in Fig. 2). In the phylogenetic result, the Boulenophrys samples from Ehuangzhang NR, Yangchun, formed three independent clades. Among them, samples (GEP asp062 and GEP asp064) from two uncaptured tadpoles clustered with the typical series of B. acuta from Heishiding NR, Fengkai, and that from Mt. Yunkai (Song et al. 2024), Xinyi, with good support (BS = 74; BPP = 0.95). In addition, samples (GEP asp061, GEP asp063, and GEP asp065–066) from four uncaptured tadpoles clustered with the typical series of B. yunkaiensis from Mt. Yunkai, Xinyi, with strong support (BS = 97; BPP = 0.99), and showed very shallow divergence. Thus, B. acuta and B. yunkaiensis were Herpetozoa 38: 345–357 (2025) herpetozoa.pensoft.net 349 Table 1. Literature for morphological characters of 78 recognized species of Boulenophrys. ID Boulenophrys spp. References 1B. acuta (Wang, Li & Jin, 2014) Lyu et al. 2023 2B. angka (Wu, Suwannapoom, Poyarkov, Pawangkhanant, Xu, Jin, Murphy & Che, 2019) Wu et al. 2019 3B. anlongensis (Li, Lu, Liu & Wang, 2020) Li et al. 2020; Lyu et al. 2023 4B. baishanzuensis (Wu, Li, Liu, Wang & Wu, 2020) Wu et al. 2020 5B. baolongensis (Ye, Fei & Xie, 2007) Ye et al. 2007; Fei and Ye 2016 6B. binchuanensis (Ye & Fei, 1995) Lyu et al. 2023 7B. binlingensis (Jiang, Fei & Ye, 2009) Fei et al. 2009; Lyu et al. 2023 8B. boettgeri (Boulenger, 1899) Lyu et al. 2023 9B. brachykolos (Inger & Romer, 1961) Lyu et al. 2023 10 B. caobangensis (Nguyen, Pham, Nguyen, Luong & Ziegler, 2020) Nguyen et al. 2020 11 B. caudoprocta (Shen, 1994) Shen 1994; Lyu et al. 2023 12 B. congjiangensis(Luo, Wang, Wang, Lu, Wang, Deng & Zhou, 2021) Lyu et al. 2023 13 B. changyangensis Li, Shi, Liu, Zhao, Gao & Wang, 2025 Li et al. 2025 14 B. cheni (Wang & Liu, 2014) Lyu et al. 2023 15 B. chishuiensis (Xu, Li, Liu, Wei & Wang, 2020) Lyu et al. 2023 16 B. daiyunensis (Lyu, Wang & Wang, 2021) Lyu et al. 2023 17 B. dalaolingensis Wang, Chen & Liu, 2025 Wang et al. 2025a 18 B.daoji(Lyu, Zeng, Wang & Wang, 2021) Lyu et al. 2023 19 B. daweimontis (Rao & Yang, 1997) Rao and Yang 1997 20 B. daxuemontis Liu, Li, Cheng, Wei, Wang & Cheng, 2025 Liu et al. 2025 21 B. dongguanensis (Wang & Wang, 2019) Lyu et al. 2023 22 B. dupanglingensis Xiao & Mo, 2025 Xiao et al. 2025 23 B. elongata Zeng, Wang, Chen, Xiao, Zhan, Li & Lin, 2024 Zeng et al. 2024 24 B. fengshunensis Wang, Zeng, Lyu & Wang, 2022 Lyu et al. 2023 25 B.fanjingmontis(Zhang, Liang, Ran & Shen, 2012) Lyu et al. 2023 26 B. fansipanensis (Tapley, Cutajar, Mahony, Nguyen, Dau, Luong, Le, Nguyen, Nguyen, Portway, Luong & Rowley, 2018) Tapley et al. 2018a 27 B. frigida (Tapley, Cutaja, Nguyen, Portway, Mahony, Nguyen, Harding, Luong & Rowley, 2021) Tapley et al. 2021 28 B. gaolanensis Song, Wang, Qi, Wang & Wang, 2024 Song et al. 2024 29 B. gutu Kuang, Wei & Shi, 2025 Kuang et al. 2025 30 B. hoanglienensis (Tapley, Cutajar, Mahony, Nguyen, Dau, Luong, Le, Nguyen, Nguyen, Portway, Luong & Rowley, 2018) Tapley et al. 2018a 31 B. huangniushiensis Wang, Wu, Song, Huang, Zhuo & Wang, 2025 Wang et al. 2025b 32 B. hungtai Wang, Zeng, Lyu, Xiao & Wang, 2022 Lyu et al. 2023 33 B. hengshanensis Qian, Hu, Mo, Gao, Zhang & Yang, 2023 Qian et al. 2023 34 B. insularis (Wang, Liu, Lyu, Zeng & Wang, 2017) Lyu et al. 2023 35 B. jiangi(Liu, Li, Wei, Xu, Cheng, Wang & Wu, 2020) Lyu et al. 2023 36 B. jingdongensis (Fei & Ye, 1983) Fei et al. 1983; Lyu et al. 2023 37 B. jinggangensis(Wang, 2012) Lyu et al. 2023 38 B.jiulianensis (Wang, Zeng, Lyu & Wang, 2019) Lyu et al. 2023 39 B. kuatunensis (Pope, 1929) Lyu et al. 2023 40 B. leishanensis (Li, Xu, Liu, Jiang, Wei & Wang, 2018) Lyu et al. 2023 41 B. lushanensis Shen, Zhou & Li, 2025 Shen et al. 2025 42 B. lushuiensis (Shi, Li, Zhu, Jiang, Jiang & Wang, 2021) Lyu et al. 2023 43 B. lichun Lin, Chen, Li, Peng, Zeng & Wang, 2024 Lin et al. 2024 44 B. liboensis (Zhang, Li, Xiao, Li, Pan, Wang, Zhang & Zhou, 2017) Zhang et al. 2017 45 B. lini (Wang & Yang, 2014) Lyu et al. 2023 46 B. lishuiensis (Wang, Liu & Jiang, 2017) Lyu et al. 2023 47 B. minor (Stejneger, 1926) Lyu et al. 2023 48 B. mirabilis (Lyu, Wang & Zhao, 2020) Lyu et al. 2023 49 B. mufumontana (Wang, Lyu & Wang, 2019) Lyu et al. 2023 50 B. nankunensis (Wang, Zeng & Wang, 2019) Lyu et al. 2023 51 B. nanlingensis (Lyu, Wang, Liu & Wang, 2019) Lyu et al. 2023 52 B. obesa (Wang, Li & Zhao, 2014) Lyu et al. 2023 53 B. ombrophila (Messenger & Dahn, 2019) Lyu et al. 2023 54 B. omeimontis (Liu, 1950) Lyu et al. 2023 55 B. palpebralespinosa (Bourret, 1937) Fei et al. 2009; Lyu et al. 2023 56 B. pepe (Wang & Zeng, 2024) Wang et al. 2024 57 B. puningensis Wang, Zeng, Lyu, Xiao & Wang, 2022 Lyu et al. 2023 58 B. qianbeinsis (Su, Shi, Wu, Li, Yao, Wang & Li, 2020) Lyu et al. 2023 59 B. rubrimera (Tapley, Cutajar, Mahony, Chung, Dau, Nguyen, Luong & Rowley, 2017) Tapley et al. 2017, 2018b 60 B. sangzhiensis (Jiang, Ye & Fei, 2008) Lyu et al. 2023 61 B. sanmingensis (Lyu & Wang, 2021) Lyu et al. 2023 62 B. shimentaina (Lyu, Liu & Wang, 2020) Lyu et al. 2023 63 B. shuichengensis (Tian & Sun, 1995) Tian and Sun 1995; Tian et al. 2000; Fei and Ye 2016 64 B. shunhuangensis (Wang, Deng, Liu, Wu & Liu, 2019) Lyu et al. 2023 herpetozoa.pensoft.net Yi-Yang Zhao et al.: A new species of Boulenophrys350 verified to be distributed in Ehuangzhang Nature Reserve based on molecular data, which also confirms the expansion of the distribution range of the two species. As the distribution range of the critically endangered B. acuta has been exceptionally underestimated, we suggest an update for the extinction risk assessment below. Additionally, samples taken from five captured adult specimens (GEP a168–170, SYS a009518, and CIB 121751) formed a monophyletic lineage with strong support (BS = 100; BPP = 1.00). This new lineage is a sister taxon to B. acuta with strong support (BS = 97; BPP = 1.00) and significant divergence with a mean p-distance of 6.5% (Suppl. material 2). Further morphological examination also showed that the corresponding specimens of the new lineage can be distinguished from all recognized congeners. Thus, we describe the corresponding specimens as a new species, which is sympatric with B. acuta and B. yunkaiensis. Taxonomic account Boulenophrys yangchunensis sp. nov. https://zoobank.org/E1D9D803-9BC7-4933-AB38-13B26681B7DC Figs 3, 4 English name: Yangchun Horned Toad Chinese name: yáng chūn jiǎo chán (阳春角蟾) Type materials. Holotype • ♂.GEP a170, collected by Jian Wang, Zhao-Chi Zeng, Hong-Hui Chen, Yuan-Hang Li, and Ke Zheng on 11 August 2023 from Guangdong Yangchun Ehuangzhang Provincial Nature Reserve (21.851912°N, 111.421553°E; ca. 1,060 m a.s.l.) in Yangchun City, Guangdong Province, China. Paratypes. •4 ♂: GEP a168–169, SYS a009518 (field number: GEP a172), and CIB 121751 (field number: GEP a171), same collection data as holotype. Etymology. The specific epithet yangchunensis is in reference to the type locality, Yangchun City. Diagnosis. (1) small size (SVL 27.6–28.7 mm in five adult males); (2) snout sharpened in dorsal view, canthus rostralis well developed, tongue not notched distally; (3) tympanum distinct; (4) vomerine ridges and vomerine teeth absent; (5) dorsal skin rough and highly granular, discontinuous X-shaped ridge on center of dorsum, discontinuous dorsolateral ridges present, sparse large tubercles on flanks, dorsal limbs with discontinuous transverse ridges and tubercles; (6) outer margin of upper eyelid with a small horn-like prominent tubercle, supratympanic fold distinct and narrow, curving posteroventrally to above arm; (7) two metacarpal tubercles distinct, inner one observably enlarged, relative finger lengths I < II < IV < III, distinct subarticular tubercle at base of each finger; (8) heels just meeting when hindlimbs folded, tibio-tarsal articulation reaching middle to anterior corner of eye; (9) toes without webbing and lateral fringes, inner metatarsal tubercle long ovoid, outer one absent, relative toe length I < II < V < III < IV; (10) dorsal surface yellowish-brown to dark brown, with indistinct irregular dark-brown patches and small orange dots; dark-brown triangular marking between eyes; dorsal limbs and digits light brown with dark-brown transverse bands; and (11) a single nuptial pad bearing dense nuptial spines on dorsal bases of fingers I and II in breeding adult males, subgular vocal sac present in males. Comparisons. Boulenophrys yangchunensis sp. nov. is phylogenetically most closely related to B. acuta and B. gaolanensis (Fig. 2). However, the new species distinctively differs from B. acuta by its heels meeting when hindlimbs are folded (vs. heels not meeting), absence of vomerine ridge (vs. presence of weak vomerine ridge), absence of webbing and lateral fringes on toes (vs. presence of rudimentary webbing and narrow lateral fringes on toes), presence of nuptial pads bearing dense nuptial spines on dorsal bases of fingers I and II in breeding adult males (vs. presence of weak nuptial pads not bearing nuptial spines on dorsal bases of fingers I and II in breeding adult males). The new species further differs from B. gaolanensis by its heels meeting when hindlimbs folded (vs. heels not meeting), sharpened snout in dorsal view (vs. rounded snout in dorsal view), presence of nuptial pad bearing dense nuptial spines on dorsal bases of fingers I and II in breeding adult males (vs. nuptial pad and nuptial spines invisible). Boulenophrys yangchunensis sp. nov. can be easily distinguished from B. brachykolos, B. daoji, B. daweimontis, B. dongguanensis, B. fengshunensis, B. frigida, B. hungtai, B. hengshanensis, B. kuatunensis, B. lichun, B. lushanensis, B. nankunensis, B. puningensis, B. pepe, ID Boulenophrys spp. References 65 B. spinata (Liu & Hu, 1973) Hu et al. 1973; Lyu et al. 2023 66 B. tongboensis (Wang & Lyu, 2021) Lyu et al. 2023 67 B. tuberogranulata (Shen, Mo & Li, 2010) Mo et al. 2010; Fei and Ye 2016; Lyu et al. 2023 68 B. wugongensis (Wang, Lyu & Wang, 2019) Lyu et al. 2023 69 B. wuliangshanensis (Ye & Fei, 1995) Lyu et al. 2023 70 B. wushanensis (Ye & Fei, 1995) Ye and Fei 1995; Fei and Ye 2016; Lyu et al. 2023 71 B. xiangnanensis (Lyu, Zeng & Wang, 2020) Lyu et al. 2023 72 B. xianjuensis(Wang, Wu, Peng, Shi, Lu & Wu, 2020) Lyu et al. 2023 73 B. xuefengmontis Lyu & Wang, 2023 Lyu et al. 2023 74 B. yangmingensis (Lyu, Zeng & Wang, 2020) Lyu et al. 2023 75 B. yaoshanensis Qi, Mo, Lyu, Wang & Wang, 2021 Lyu et al. 2023 76 B. yezhongensis Liu, Feng, Shen, Li, Cheng, Wei, Wang & Su, 2025 Liu et al. 2025 77 B. yingdeensis Qi, Lyu, Wang & Wang, 2021 Lyu et al. 2023 78 B. yunkaiensis Qi, Wang, Lyu & Wang, 2021 Lyu et al. 2023 Herpetozoa 38: 345–357 (2025) herpetozoa.pensoft.net 351 B. insularis, B. obesa, B. ombrophila, and B. wugongensis, by its heels meeting when hindlimbs folded (vs. heels not meeting); and from B. anlongensis, B. baishanzuensis, B. binlingensis, B. caudoprocta, B. cheni, B. changyangensis,B.congjiangensis, B. changyangensis, B. chishuiensis, B. daxuemontis, B. dalaolingensis, B. dupanglingensis, B. fanjingmontis, B. jiangi, B. jiulianensis, B. jingdongensis,B.jinggangensis, B. leishanensis, B. lushuiensis, B. liboensis, B. lini, B. lishuiensis, B. mirabilis, B. mufumontana, B. nanlingensis, B. omeimontis, B. palpebralespinosa, B. qianbeiensis, B. sangzhiensis, B. shunhuangensis, B. sanmingensis, B. shimentaina, B. spinata, B. tongboensis, B. tuberogranulata, B. xianjuensis, B. yangmingensis, B. yezhongensis, B. yingdeensis, B. yunkaiensis, and B. wuliangshanensis (vs. heels overlapping). Boulenophrys yangchunensis sp. nov. further differs from B. angka, B. anlongensis, B. baishanzuensis, B. binlingensis, B. elongata, B. fansipanensis, B. hoanglienensis, B. minor, B. rubrimera, B. shuichengensis, B. xiangnanensis, B. yaoshanensis, and B. yezhongensis by its absence of vomerine ridge (vs. presence of vomerine ridge); from B. daiyunensis, B. elongata, B. fansipanensis, B. hoanglienensis, and B. rubrimera by its absence of vomerine teeth (vs. presence of vomerine teeth); and from B. baolongensis and B. boettgeri by its tongue not notched distally (vs. tongue notched). The new species differs from B. wushanensis and B. gutu by its absence of lateral fringes on toes (vs. presence of lateral fringes on toes); from B. yaoshanensis and B. caobangensis by its absence of webbing on toes (vs. presence of webbing on toes); from B. xuefengmontis by its tibiotarsal articulation reaching region between middle of eye to anterior corner of eye when legs are stretched forward (vs. between posterior margin of tympanum and posterior corner of eye), and the absence of granules on ventral skin (vs. presence of several granules on chest); from B. huangniushiensis by its presence of nuptial pads bearing nuptial spines in males (vs. absence of nuptial pads or nuptial spines). Description of holotype. Adult male. Body size small, SVL 27.9 mm. Head length almost equal to head width, HDW/HDL 1.00; snout sharpened in dorsal view, projecting, sloping backward to mouth in profile, protruding well beyond margin of lower jaw; top of head flat; eyes moderate in size, ED 0.40 of HDL, pupil vertical, near diamond-shaped; nostril obliquely ovoid; canthus rostralis well developed; loreal region slightly oblique; internasal distance slightly larger than interorbital distance; tympanic region oblique, tympanum distinct and visible in dorsal view; tympanum moderate in size, margin clear, upper margin in contact with supratympanic fold, lower margin in contact with upper lip, TD/ED 0.50; large ovoid choanae at base of maxilla; vomerine ridge and vomerine teeth absent, maxillary teeth present; margin of tongue rounded, not notched distally; presence of single subgular vocal sac. Forearm length 0.20 of SVL, hand 0.30 of SVL; webbing absent between fingers, lateral fringes absent, relative finger length I < II < IV < III; tips of fingers slightly dilated, round; subarticular tubercles on base of fingers present, distinct; inner metacarpal tubercle Figure 3. The holotype (GEP a170) of Boulenophrys yangchunensis sp. nov. in preservative: dorsal view (A); ventral view (B); ventral view of hand (C); ventral view of foot (D). Photos by Jian Wang. herpetozoa.pensoft.net Yi-Yang Zhao et al.: A new species of Boulenophrys352 observably enlarged, outer one slightly smaller; single nuptial pad bearing dense nuptial spines present on dorsal surface of first and second fingers, respectively. Hindlimbs moderate in length, tibio-tarsal articulation reaching forward to anterior corner of eye when hindlimb stretched along body; heels just meeting when flexed hindlimbs held at right angles to body axis; crus length 0.50 of SVL and foot length 0.70 of SVL; relative toe length I < II < V < III < IV; tips of toes round and slightly dilated; toes without lateral fringes and webbing; subarticular tubercles on base of toes present and distinct; inner metatarsal tubercle long ovoid and lacking outer metatarsal tubercle. Dorsal skin rough and highly granular; dense large tubercles on flanks; single horn-like prominent tubercle on edge of upper eyelid; obvious supratympanic fold curving posteroventrally from posterior corner of eye to level above insertion of arm; discontinuous X-shaped ridge on center of dorsum, discontinuous dorsolateral ridges present; dorsal limbs with discontinuous transverse ridges and tubercles; ventral surface smooth; small and distinct pectoral gland closer to axilla; single femoral gland positioned on posterior surface of thigh at midpoint between knee and cloaca. Coloration of holotype. In life, dorsal surface of body yellowish-brown with indistinct irregular dark-brown patches and small orange dots, dark-brown triangular marking between eyes. A vertical dark-brown band present below eye. Tympanum light brown. Dorsal surface of limbs with darkbrown transverse bands. Tubercles on edge of upper eyelids orange. Supratympanic fold grey white. Iris coppery brown. In preservative, dorsal surface of body greyish-brown, with markings and patches more distinct. Surface of chest, throat and limbs are yellowish brown, with distinct dark-brown markings and greyish-white patches. Pectoral glands and femoral glands greyish-white. Variation. Morphometric variations are listed in Table 2. Most of the paratypes are similar to the holotype in morphology and color pattern, except for the following: tibio-tarsal articulation reaching forward to middle of eye when hindlimb stretched along body in the paratype GEP a171; head width larger than head length in the paratype SYS a009518; dorsal coloration yellowish-brown, greyish-brown to dark brown (Fig. 4). Figure 4. Life aspect of Boulenophrys yangchunensis sp. nov.: holotype GEP a170 (A, B); paratype GEP a168 (C); paratype GEP a172 (D). Photos by Jian Wang. Herpetozoa 38: 345–357 (2025) herpetozoa.pensoft.net 353 Distribution and natural history. Currently, Boulenophrys yangchunensis sp. nov. is only known from the type locality, Guangdong Yangchun Ehuangzhang Provincial Nature Reserve, western Guangdong, China. It inhabits flowing montane streams and the nearby forest floor and leaf litter. The habitat is surrounded by evergreen broad-leaved forest mixed with bamboo groves at elevations between 900 and 1,100 m (Fig. 5). Advertisement calls of males were heard from February to May. Males were found calling while perching on leaves that are 10–30 cm above the ground. Conservation status of relevant Boulenophrys species in Guangdong Recommendation for extinction risk assessment for Boulenophrys acuta Distribution: Heishiding Nature Reserve, Fengkai County, Zhaoqing, Guangdong Province, China (Li et al. 2014; Lyu et al. 2023); Mt. Yunkai, Xinyi City, Guangdong Province, China (Song et al. 2024); Guangdong Yangchun Ehuangzhang Provincial Nature Reserve, Yangchun City, Guangdong Province, China (this study). Extinction risk assessment: based on the analysis on GeoCAT, we determined an AOO of 3,170 km2 and an AOO of 12 km2. As the species is found at three independent locations (to assess against criteria B2a), and there is a continued observed decline in the (iii) quality of the habitat, we recommend the species be listed as Endangered following the criteria B1ab(iii) and B2ab(iii). If relying on the criteria D (very small population and/ or restricted distribution) for the recommendation of assessment, the species would be listed as Vulnerable D2 because the AOO is smaller than 20 km² and the species occurs at fewer than five locations. This recommendation for assessment is a non-genuine downlisting (ASG Table 2. Measurements (in mm) of voucher specimens of Boulenophrys yangchunensis sp. nov., * holotype. Voucher GEP a168 GEP a169 GEP a170* CIB 121751 SYS a009518 Sex ♂ ♂ ♂ ♂ ♂ SVL 28.6 27.6 27.9 28.6 28.7 HDL 10.4 10.1 11.1 10.6 10.4 HDW 10.3 9.7 11.0 10.4 10.6 ED 3.7 3.6 3.8 4.0 3.7 TD 3.5 3.1 3.7 3.5 3.6 TED 3.1 3.0 3.2 3.4 3.3 SNT 3.8 3.7 4.1 3.6 3.5 IND 2.1 2.0 2.0 2.2 2.0 IOD 1.2 1.3 1.1 1.2 1.2 HND 7.8 7.8 7.9 8.1 7.6 RAD 6.0 6.1 6.5 5.9 5.9 FTL 19.9 20.1 20.7 19.7 19.7 TIB 14.0 13.8 14.5 13.3 14.1 Figure 5. Microhabitat of Boulenophrys yangchunensis sp. nov. in Guangdong Yangchun Ehuangzhang Provincial Nature Reserve, Yangchun City, Guangdong Province, China. Photos by Bin-Bin Zhan.