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Research Article
Sinocyclocheilus longicornus (Cypriniformes, Cyprinidae), a new species of microphthalmic hypogean fish from Guizhou, Southwest China
expand article infoCheng Xu‡, Tao Luo‡, Jia-Jun Zhou§|, Li Wu‡, Xin-Rui Zhao‡, Hong-Fu Yang, Ning Xiao#, Jiang Zhou‡
‡ Guizhou Normal University, Guiyang, China
§ Zhejiang Forest Resource Monitoring Center, Hangzhou, China
| Zhejiang Forestry Survey Planning and Design Company Limited, Hangzhou, China
¶ Fishery Adminstration of Qiubei County, Qiubei, China
# Guiyang Healthcare Vocational University, Guiyang, China

Corresponding author: Jiang Zhou ( zhoujiang@ioz.ac.cn )

Academic editor: Sven Kullander
© 2023 Cheng Xu, Tao Luo, Jia-Jun Zhou, Li Wu, Xin-Rui Zhao, Hong-Fu Yang, Ning Xiao, Jiang Zhou.
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.
Citation: Xu C, Luo T, Zhou J-J, Wu L, Zhao X-R, Yang H-F, Xiao N, Zhou J (2023) Sinocyclocheilus longicornus (Cypriniformes, Cyprinidae), a new species of microphthalmic hypogean fish from Guizhou, Southwest China. ZooKeys 1141: 1-28. https://doi.org/10.3897/zookeys.1141.91501
ZooBank: urn:lsid:zoobank.org:pub:B816E2E2-3841-4433-9CFC-8BF350BEDA97
Open Access

Abstract

Sinocyclocheilus longicornus sp. nov. is described from the Pearl River basin in Hongguo Town, Panzhou City, Guizhou Province, Southwest China. Based on the presence of the long horn-like structure on the back of the head, Sinocyclocheilus longicornus sp. nov. is assigned to the Sinocyclocheilus angularis species group. Sinocyclocheilus longicornus sp. nov. is distinguished from its congeners by a combination of morphological characters: (1) presence of a single, relatively long horn-like structure on the back of the head; (2) pigmentation absent; (3) reduced eyes; (4) dorsal-fin rays, ii, 7; (5) pectoral-fin rays, i, 13; (6) anal-fin rays, iii, 5; (7) pelvic-fin rays, i, 7; (8) lateral line pores 38–49; (9) gill rakers well developed, nine on first gill arch; and (10) tip of adpressed pelvic fin not reaching anus.

Keywords

cave fish, morphology, taxonomy, phylogeny

Introduction

The golden-line fish genus Sinocyclocheilus Fang, 1936, is endemic to China, and is mainly distributed in the karst areas of Southwest China, including Guangxi, Guizhou, Yunnan, and Hubei provinces (Zhao and Zhang 2009; Jiang et al. 2019). The narrow distribution, morphological similarities, and morphological adaptations to cave environments, such as the degeneration or loss of eyes and body scales, have made classification of the genus difficult and often controversial (Chu and Cui 1985; Shan and Yue 1994; Wang et al. 1995; Wang and Chen 1998; Wang et al. 1999; Wang and Chen 2000; Xiao et al. 2005; Mao et al. 2021, 2022; Wen et al. 2022). A phylogenetic study based on the mitochondrial cytochrome b gene (Cyt b) showed that all members of Sinocyclocheilus clustered as a monophyletic group, divided into four species groups, namely the S. jii, S. angularis, S. cyphotergous, and S. tingi groups (Zhao and Zhang 2009). However, phylogenetic studies based on restriction site–associated DNA sequencing and mitochondrial genome reconstruction suggest that the S. angularis and S. cyphotergous species groups are not monophyletic (Xiang 2014; Liu 2018; Mao et al. 2021, 2022; Wen et al. 2022). Sinocyclocheilus comprises 76 valid species, of which 71 species are grouped into five species groups (Table 1).

Table 1.
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List of 76 currently recognized species of the genus Sinocyclocheilus endemic to China and references. Recognized species modified from Jiang et al. (2019).

ID Species Species group Province River Reference
1 S. altishoulderus (Li & Lan, 1992) S. angularis group Guangxi Hongshuihe River Li and Lan 1992
2 S. anatirostris Lin & Luo, 1986 S. angularis group Guangxi Hongshuihe River Lin and Luo 1986
3 S. angularis Zheng & Wang, 1990 S. angularis group Guizhou Nanpanjiang River Zheng and Wang 1990
4 S. aquihornes Li & Yang, 2007 S. angularis group Yunnan Nanpanjiang River Li et al. 2007
5 S. bicornutus Wang & Liao, 1997 S. angularis group Guizhou Beipanjiang River Wang and Liao 1997
6 S. brevibarbatus Zhao, Lan & Zhang, 2009 S. angularis group Guangxi Hongshuihe River Zhao et al. 2009
7 S. broadihornes Li & Mao, 2007 S. angularis group Yunnan Nanpanjiang River Li and Mao 2007
8 S. convexiforeheadus Li, Yang & Li, 2017 S. angularis group Yunnan Nanpanjiang River Yang et al. 2017
9 S. hyalinus Chen & Yang, 1994 S. angularis group Yunnan Nanpanjiang River Chen et al. 1994
10 S. jiuxuensis Li & Lan, 2003 S. angularis group Guangxi Hongshuihe River Li et al. 2003c
11 S. flexuosdorsalis Zhu & Zhu, 2012 S. angularis group Guangxi Hongshuihe River Zhu and Zhu 2012
12 S. furcodorsalis Chen, Yang & Lan, 1997 S. angularis group Guangxi Hongshuihe River Chen et al. 1997
13 S. mashanensis Wu, Liao & Li, 2010 S. angularis group Guangxi Hongshuihe River Wu et al. 2010
14 S. rhinocerous Li & Tao, 1994 S. angularis group Yunnan Nanpanjiang River Li and Tao 1994
15 S. simengensis Li, Wu, Li & Lan, 2018 S. angularis group Guangxi Hongshuihe River Wu et al. 2018
16 S. tianeensis Li, Xiao & Luo, 2003 S. angularis group Guangxi Hongshuihe River Li et al. 2003d
17 S. tianlinensis Zhou, Zhang, He & Zhou, 2004 S. angularis group Guangxi Nanpanjiang River Zhou et al. 2004
18 S. tileihornes Mao, Lu & Li, 2003 S. angularis group Yunnan Nanpanjiang River Mao et al. 2003
19 S. zhenfengensis Liu, Deng, Ma, Xiao & Zhou, 2018 S. angularis group Guizhou Beipanjiang River Liu et al. 2018
20 S. anshuiensis Gan, Wu, Wei & Yang, 2013 S. microphthalmus group Guangxi Hongshuihe River Gan et al. 2013
21 S. microphthalmus Li, 1989 S. microphthalmus group Guangxi Hongshuihe River Li 1989
22 S. aluensis Li & Xiao, 2005 S. tingi group Yunnan Nanpanjiang River Li et al. 2005; Zhao and Zhang 2013
23 S. angustiporus Zheng & Xie, 1985 S. tingi group Guizhou; Yunnan Beipanjiang River; Nanpanjiang River Zheng and Xie 1985
24 S. anophthalmus Chen & Chu, 1988 S. tingi group Yunnan Nanpanjiang River Chen et al. 1988a Zhao and Zhang 2009
25 S. grahami (Regan, 1904) S. tingi group Yunnan Jinshajiang River Regan 1904; Zhao and Zhang 2009
26 S. guishanensis Li, 2003 S. tingi group Yunnan Nanpanjiang River Li et al. 2003a
27 S. huaningensis Li, 1998 S. tingi group Yunnan Nanpanjiang River Li et al. 1998
28 S. huizeensis Cheng, Pan, Chen, Li, Ma & Yang, 2015 S. tingi group Yunnan Niulanjiang River Cheng et al. 2015
29 S. bannaensis Li, Li & Chen, 2019 S. tingi group Yunnan Luosuojiang River Li et al. 2019
30 S. maculatus Li, 2000 S. tingi group Yunnan Nanpanjiang River Zhao and Zhang 2009
31 S. maitianheensis Li,1992 S. tingi group Yunnan Nanpanjiang River Li 1992
32 S. malacopterus Chu & Cui, 1985 S. tingi group Yunnan Nanpanjiang River Chu and Cui 1985
33 S. longifinus Li, 1998 S. tingi group Yunnan Nanpanjiang River Li et al. 1998
34 S. longshanensis Li & Wu, 2018 S. tingi group Yunnan Nanpanjiang River Li et al. 2018
35 S. macrocephalus Li,1985 S. tingi group Yunnan Nanpanjiang River Li 1985
36 S. lateristriatus Li,1992 S. tingi group Yunnan Nanpanjiang River Li 1992
37 S. purpureus Li, 1985 S. tingi group Yunnan Nanpanjiang River Li 1985
38 S. qiubeiensis Li, 2002 S. tingi group Yunnan Nanpanjiang River Li et al. 2002b
39 S. qujingensis Li, Mao & Lu, 2002 S. tingi group Yunnan Nanpanjiang River Li et al. 2002c
40 S. robustus Chen & Zhao, 1988 S. tingi group Guizhou Nanpanjiang River Chen et al. 1988b
41 S. wumengshanensis Li, Mao, Lu & Yan, 2003 S. tingi group Yunnan Niulanjiang River Li et al. 2003a
42 S. xichouensis Pan, Li, Yang & Chen, 2013 S. tingi group Yunnan Panlonghe River Pan et al. 2013
43 S. tingi Fang, 1936 S. tingi group Yunnan Nanpanjiang River Fang, 1936; Zhao and Zhang 2009
44 S. yangzongensis Chu & Chen, 1977 S. tingi group Yunnan Nanpanjiang River Wu 1977; Zhao and Zhang 2009
45 S. yimenensis Li & Xiao, 2005 S. tingi group Yunnan Yuanjiang River Li et al. 2005
46 S. oxycephalus Li, 1985 S. tingi group Yunnan Nanpanjiang River Li 1985
47 S. brevis Lan & Chen, 1992 S. cyphotergous group Guangxi Liujiang River Chen and Lan 1992
48 S. cyphotergous (Dai, 1988) S. cyphotergous group Guizhou Hongshuihe River Dai 1988; Huang et al. 2017
49 S. donglanensis Zhao, Watanabe & Zhang, 2006 S. cyphotergous group Guangxi Hongshuihe River Zhao et al. 2006
50 S. dongtangensis Zhou, Liu & Wang, 2011 S. cyphotergous group Guizhou Liujiang River Zhou et al. 2011
51 S. huanjiangensis Wu, Gan & Li, 2010 S. cyphotergous group Guangxi Liujiang River Wu et al. 2010
52 S. hugeibarbus Li, Ran & Chen, 2003 S. cyphotergous group Guizhou Liujiang River Li et al. 2003b
53 S. gracilicaudatus Zhao & Zhang, 2014 S. cyphotergous group Guangxi Liujiang River Wang et al. 2014
54 S. lingyunensis Li, Xiao & Lu, 2000 S. cyphotergous group Guangxi Hongshuihe River Li et al. 2000
55 S. longibarbatus Wang & Chen, 1989 S. cyphotergous group Guizhou; Guangxi Liujiang River Wang and Chen 1989
56 S. luopingensis Li & Tao, 2002 S. cyphotergous group Yunnan Nanpanjiang River Li et al. 2002a
57 S. macrolepis Wang & Chen, 1989 S. cyphotergous group Guizhou; Guangxi Liujiang River Wang and Chen 1989
58 S. macrophthalmus Zhang & Zhao, 2001 S. cyphotergous group Guangxi Hongshuihe River Zhang and Zhao 2001
59 S. macroscalus Li, 1992 S. tingi group Yunnan Nanpanjiang River Li 1992
60 S. multipunctatus (Pellegrin, 1931) S. cyphotergous group Guizhou; Guangxi Wujiang River; Liujiang River; Hongshuihe River Pellegrin 1931; Zhao and Zhang 2009
61 S. punctatus Lan & Yang, 2017 S. cyphotergous group Guizhou; Guangxi Liujiang River; Hongshuihe River Lan et al. 2017
62 S. ronganensis Luo, Huang & Wen, 2016 S. cyphotergous group Guangxi Liujiang River Luo et al. 2016
63 S. xunlensis Lan, Zhan & Zhang, 2004 S. cyphotergous group Guangxi Liujiang River Lan et al. 2004
64 S. yaolanensis Zhou, Li & Hou, 2009 S. cyphotergous group Guizhou Liujiang River Zhou et al. 2009
65 S. yishanensis Li & Lan, 1992 S. cyphotergous group Guangxi Liujiang River Li and Lan 1992
66 S. sanxiaensis Jiang, Li, Yang & Chang, 2019 S. cyphotergous group Hubei Yangtze River Jiang et al. 2019
67 S. brevifinus Li, Li & Mayden, 2014 S. jii group Guangxi Hejiang River Li et al. 2014
68 S. guanyangensis Chen, Peng & Zhang, 2016 S. jii group Guangxi Guijiang River Chen et al. 2016
69 S. guilinensis Ji, 1985 S. jii group Guangxi Guijiang River Zhou 1985; Zhao and Zhang 2009
70 S. huangtianensis Zhu, Zhu & Lan, 2011 S. jii group Guangxi Hejiang River Zhu et al. 2011
71 S. jii Zhang & Dai, 1992 S. jii group Guangxi Guijiang River Zhang and Dai 1992
72 S. gracilis Li & Li, 2014 No assignment Guangxi Guijiang River Li and Li 2014
73 S. pingshanensis Li, Li, Lan & Wu, 2018 No assignment Guangxi Liujiang River Wu et al. 2018
74 S. wenshanensis Li,Yang, Li & Chen, 2018 No assignment Yunnan Panlonghe River Yang et al. 2018
75 S. wui Li & An, 2013 No assignment Yunnan Mingyihe River Li and An 2013
76 S. luolouensis Lan, 2013 No assignment Guangxi Hongshuihe River Lan et al. 2013

Species of Sinocyclocheilus have variably developed eyes and horn-like structures on the back of the head. Eye morphology includes normal, microphthalmic, and anophthalmic conditions (Mao et al. 2021). Normal-eyed and microphthalmic species are distributed from eastern Guangxi through southern Guizhou to eastern Yunnan, and eyeless species are mainly distributed in the Hongshuihe river basin in northern Guangxi and the Nanpanjiang river basin in eastern Yunnan (Mao et al. 2021). It may be absent, short, long, or single and forked. The horn-like structure is present mainly in species of the S. angularis and S. microphthalmus species groups (Zhao and Zhang 2009; Mao et al. 2021; Wen et al. 2022). These horned species are distributed in the Nanpanjiang, Beipanjiang, and Hongshuihe river basins of the upper Pearl River (Fig. 1).

Figure 1. 

Sampling collection localities and distribution of the Sinocyclocheilus longicornus sp. nov. and 21 species of the S. angularis and S. microphthalmus species groups of the genus Sinocyclocheilus in Southwest China. 1. Hongguo Town, Panzhou City, Guizhou Province. 2. Baotian Town, Panzhou City, Guizhou Province. 3. Xinlongchang Town, Xingren City, Guizhou Province. 4. Zhexiang Town, Zhenfeng County, Guizhou Province. 7. Huancheng Town, Luoping County, Yunnan Province. 5–6, 8–22 is detailed in Suppl. material 1. The maps are from Standard Map Service website (http://bzdt.ch.mnr.gov.cn/index.html).

We collected specimens of a horned, scaleless, and unpigmented species of Sinocyclocheilus in a completely dark cave in southwestern Guizhou Province in China. Molecular phylogenetic analyses and morphological comparisons showed that these specimens represented an undescribed species of Sinocyclocheilus. Here, we provide the formal description of that species as Sinocyclocheilus longicornus sp. nov.

Materials and methods

Specimen sampling

During a cavefish diversity survey in southern China in May 2021, 32 specimens of the genus Sinocyclocheilus were collected in southwestern Guizhou Province. Among these, 15 specimens represented an undescribed species, subject of this, paper from Hongguo Town in Panzhou City; seven were S. angularis from Baotian Town in Panzhou; two were S. bicornutus from Xiashan Town in Xingren City; and eight were S. zhenfengensis from Zhexiang Town in Zhenfeng County (Fig. 1). Gill muscle tissues used for molecular analysis were preserved in 95% alcohol at −20 °C. All specimens were fixed in 10% buffered formalin and later transferred to 75% ethanol for long term preservation. All specimens were deposited in Guizhou Normal University, Guiyang City, Guizhou Province, China.

DNA Extraction, PCR amplification, and sequencing

Genomic DNA was extracted from muscle tissues using a DNA extraction kit from Tiangen Biotech Co., Ltd. (Beijing, China). Because the most used molecular markers in Sinocyclocheilus are fragments of the mitochondrial cytochrome b (Cyt b) and NADH dehydrogenase subunit 4 (ND4) genes, we selected these fragments for amplification and sequencing. Primers used for Cyt b were L14737 (5’-CCACCGTTGTTAATTCAACTAC-3’) and H15915 (5’-CTCCGATCTCCGGATTACAAGAC-3’), following Xiao et al. (2005). Primers used for ND4 were L11264 (5’-ACGGGACTGAGCGATTAC-3’) and H12346 (5’-TCATCATATTGGGTTAG-3’), following Xiao et al. (2005). PCR amplifications were performed in a 25-μl reaction volume with the following cycling conditions: an initial denaturing step at 95 °C for 3 min; 35 cycles of denaturing at 94 °C for 50 s, annealing at 52 °C (for Cyt b and ND4) for 1 min and extension at 72 °C for 1 min, and a final extension step of 72 °C for 10 min. The PCR products were sequenced on an ABI Prism 3730 automated DNA sequencer at Chengdu TSING KE Biological Technology Co. Ltd. (Chengdu, China). All sequences were deposited in GenBank (Table 2).

Table 2.
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Localities, voucher information, and GenBank numbers for all samples used.

ID Species Locality (* type localities) Voucher number GenBank accession No.
Cyt b ND4
1 Sinocyclocheilus huizeensis Leye Town, Huize County, Yunnan, China hrfri2018046 MH982229 MH982229
2 Sinocyclocheilus qiubeiensis Songming, Yunnan, China IHB:2006624 EU366188 EU366182
3 Sinocyclocheilus yimenensis Yimen, Yunnan, China IHB:2006646 EU366191 EU366180
4 Sinocyclocheilus grahami Haikou, Kunming City, Yunnan, China – GQ148557 GQ148557
5 Sinocyclocheilus tingi Fuxian Lake, Yunnan, China YNUST201406180002 MG323567 MG323567
6 Sinocyclocheilus wumengshanensis Xuanwei County, Yunnan, China YNUSM20160817008 MG021442 MG021442
7 Sinocyclocheilus anophthalmus Jiuxiang, Yiliang County, Yunnan, China XH3001 AY854715 AY854772
8 Sinocyclocheilus maculatus Yiliang, Yunnan, China IHB:2006632 EU366193 EU366183
9 Sinocyclocheilus maitianheensis Jiuxiang, Yiliang County, Yunnan, China XH2301 AY854710 AY854767
10 Sinocyclocheilus lateristriatus Maojiachong, Zhanyi County, Yunnan XH1102 AY854703 AY854760
11 Sinocyclocheilus qujingensis Huize County, Yunnan, China hrfri2018044 MH937706 MH937706
12 Sinocyclocheilus guishanensis Guishan, Shilin County, Yunnan, China XH5401 AY854722 AY854779
13 Sinocyclocheilus huaningensis Huaning County, Yunnan, China XH3701 AY854718 AY854775
14 Sinocyclocheilus oxycephalus Heilongtan, Shilin County, Yunnan, China XH0201 AY854685 AY854742
15 Sinocyclocheilus macrocephalus Heilongtan, Shilin County, Yunnan XH0103 AY854683 AY854740
16 Sinocyclocheilus malacopterus Wulonghe, Shizong County, Yunnan, China XH0901 AY854697 AY854754
17 Sinocyclocheilus purpureus Luoping County, Yunnan, China IHB:2006638 EU366189 EU366178
18 Sinocyclocheilus angustiporus Xinlongchnag Town, Xingren City, Guizhou, China GZNU20210322002 MZ636515 MZ636515
19 Sinocyclocheilus yangzongensis Yangzonghai Lake, Yunnan, China XH6101 AY854725 AY854782
20 Sinocyclocheilus multipunctatus Huishui County, Guizhou, China – MG026730 MG026730
21 Sinocyclocheilus sanxiaensis Guojiaba Town, Zigui County, Hubei, China* KNHM 2019000001 MN106258 –
22 Sinocyclocheilus cyphotergous Dongdang township, Luodian County, Guizhou, China* GZNU20150819010 MW024370 MW024370
23 Sinocyclocheilus punctatus Dongtang Township, Libo County, Guizhou, China GZNU20150811002 MW014318 MW014318
24 Sinocyclocheilus macrolepis Nandan County, Guangxi, China XH8201 AY854729 AY854786
25 Sinocyclocheilus brevis – GX0155 MT373105 MW548424
26 Sinocyclocheilus huanjiangensis – GX0124 MT373103 MW548429
27 Sinocyclocheilus longibarbatus Dongtang Township, Libo County, Guizhou, China* GZNU20150809004 MW024372 MW024372
28 Sinocyclocheilus xunlensis Huanjiang, Guangxi, China IHB:04050268 EU366187 EU366184
29 Sinocyclocheilus donglanensis Hongshuihe River, Donglan County, Guangxi, China CA139 AB196440 MW548425
30 Sinocyclocheilus lingyunensis Shadong, Lingyun County, Guangxi, China XH0502 AY854691 AY854748
31 Sinocyclocheilus hugeibarbus Xiaoqikong Town, Libo County, Guizhou, China* GZNU20150120005 MW014319 MW014319
32 Sinocyclocheilus macrophthalmus Xiaao, Duan County, Guangxi, China XH8401 AY854733 AY854790
33 Sinocyclocheilus yishanensis Liujiang County, Guangxi, China – MK387704 MK387704
34 Sinocyclocheilus ronganensis Rong’an County, Guangxi, China – KX778473 KX778473
35 Sinocyclocheilus furcodorsalis Tian’e County, Guangxi, China – GU589570 GU589570
36 Sinocyclocheilus tianlinensis – GX0087-L17-16 MT373102 MW548431
37 Sinocyclocheilus anatirostris Leye County, Guangxi, China XH1901 AY854708 AY854765
38 Sinocyclocheilus anshuiensis Lingyun County, Guangxi, China – KR069120 KR069120
39 Sinocyclocheilus microphthalmus Lingyun County, Guangxi, China NNNU201712001 MN145877 MN145877
40 Sinocyclocheilus altishoulderus Mashan County, Guangxi, China – FJ984568 FJ984568
41 Sinocyclocheilus mashanensis – GX0026-L18-12 MT373107 MW548430
42 Sinocyclocheilus brevibarbatus – GX0064-L20-13 MT373106 MW548423
43 Sinocyclocheilus jiuxuensis Jiuxu Town, Hechi City, Guangxi, China XH8501 AY854736 AY854793
44 Sinocyclocheilus angularis Baotian Town, Panzhou City, Guizhou, China* GZNU20210322001 MZ636514 MZ636514
45 Sinocyclocheilus zhenfengensis Zhexiang Town, Zhenfeng County, Guizhou, China* GZNU20150112021 MW014317 MW014317
46 Sinocyclocheilus bicornutus Xinlongchnag Town, Xingren City, Guizhou, China* – KX528071 KX528071
47 Sinocyclocheilus longicornus sp. nov. Hongguo Town, Panzhou City, Guizhou, China* GZNU20210503016 MZ634123 MZ634125
48 Sinocyclocheilus longicornus sp. nov. Hongguo Town, Panzhou City, Guizhou, China* GZNU20210503017 MZ634124 MZ634126
49 Sinocyclocheilus hyalinus Alugudong, Luxi County, Yunnan, China XH4701 AY854721 AY854778
50 Sinocyclocheilus rhinocerous Luoping County, Yunnan, China – KR069119 KR069119
51 Sinocyclocheilus guanyangensis – GX0173 MT373108 MW548426
52 Sinocyclocheilus jii Gongcheng County, Guangxi, China YNUSJ201308060038 MF100765 MF100765
53 Sinocyclocheilus huangtianensis – GX0175 MT373109 MW548428
54 Sinocyclocheilus guilinensis – GX0073-L17-2 MT373104 MW548427
55 Carassius auratus – – AB111951 AB111951
56 Cyprinus carpio – – JN105357 JN105357
57 Garra orientalis – – JX290078 JX290078
58 Neolissochilus hexagonolepis – – KU380329 KU380329
59 Schizothorax yunnanensis – – KR780749 KR780749
60 Barbus barbus – – AB238965 AB238965
61 Onychostoma simum – – KF021233 KF021233
62 Pethia ticto – – AB238969 AB238969
63 Myxocyprinus asiaticus – – AY526869 AY526869
64 Danio rerio – -– KM244705 KM244705

Phylogenetic analyses

We used a total of 108 mitochondrial gene sequences for molecular analyses (55 Cyt b sequences and 53 ND4 sequences). Four samples of muscle tissues from S. Sinocyclocheilus angustiporus, S. angularis, and Sinocyclocheilus longicornus sp. nov. were sequenced for two mitochondrial genes and 100 sequences from 45 species of Sinocyclocheilus were downloaded from GenBank. Following Wen et al. (2022), we selected Carassius auratus, Cyprinus carpio, Garra orientalis, Neolissochilus hexagonolepis, Schizothorax yunnanensis, Barbus barbus, Onychostoma simum, Pethia ticto, Myxocyprinus asiaticus, and Danio rerio as outgroup (Table 2).

All sequences were assembled and aligned using the MUSCLE (Edgar 2004) module in MEGA 7.0 (Kumar et al. 2016) with default settings. Alignment results were checked by eye. Phylogenetic trees were constructed with both maximum likelihood (ML) and Bayesian inference (BI) methods. The ML was conducted in IQ-TREE 2.0.4 (Nguyen et al. 2015) with 2000 ultrafast bootstrap (UBP) replicates (Hoang et al. 2018) and was performed until a correlation coefficient of at least 0.99 was reached. The BI was performed in MrBayes 3.2.1 (Ronquist et al. 2012), and the best-fit model was obtained based on the Bayesian information criterion computed with PartitionFinder 2.1.1 (Lanfear et al. 2017). In this analysis, the first, second and third codons of both Cyt b and ND4 genes were defined.

The analysis suggested the best partition scheme for each codon position of Cyt b and ND4 genes. GTR+I+G, HKY+I+G, and TRN+I+G were selected for first, second, and third codons, respectively for both Cyt b and ND4 genes. Two independent runs were conducted in BI analysis, each of which was performed for 2 × 107 generations and sampled every 1000 generations. The first 25% of the samples were discarded as burn-in, resulting in a potential scale reduction factor of < 0.01. Nodes in the trees were considered well supported when Bayesian posterior probabilities (BPP) were ≥ 0.95 and the ML ultrafast bootstrap value (UBP) was ≥ 95%. Uncorrected p-distances (1000 replicates) based on Cyt b and ND4 genes were calculated in MEGA 7.0 (Kumar et al. 2016).

Morphological comparisons

Morphometric data were collected from 44 well-preserved specimens of Sinocyclocheilus (Suppl. material 1). A total of 31 measurements were recorded to the nearest 0.1 mm with digital calipers following the protocol of Zhao et al. (2006) and Zhao and Zhang (2009). The following measurements were taken:

TL total length (from the tip of snout to the end of the caudal-fin);

SL standard length (from the tip of the upper jaw to the position of the last half-centrum);

BD body depth (from the insertion of the dorsal fin vertically to the ventral midline);

PL predorsal length (from the tip of the upper jaw to the origin of the dorsal-fin);

DFL dorsal-fin depth (from the origin of the dorsal-fin to the tip of the longest ray);

DBL dorsal-fin length (from the origin to the insertion of dorsal-fin base);

PAL preanal length (from the tip of the upper jaw to the origin of the anal-fin);

ABL anal-fin base length (from the origin to the insertion of anal-fin base);

AFL anal-fin depth (from the origin of the anal-fin to the tip of the longest ray);

PPTL prepectoral length (from the tip of the upper jaw to the base of anterior pectoral-fin ray);

PTBL pectoral-fin base length (from the anterior to posterior end of pectoral-fin base);

PTFL pectoral-fin length (from the base of the first pectoral-fin ray to the tip of the longest ray);

PPVL prepelvic length (from the tip of the upper jaw to the base of the first pelvic-fin ray);

PVBL pelvic-fin base length (from the anterior to the posterior end of the pelvic-fin base);

PVFL pelvic-fin length (from the base of the first pelvic-fin ray to the tip of the longest ray);

CPL caudal peduncle length (from the anal-fin insertion to the position of the last centrum);

CPD caudal peduncle depth (depth at the narrowest part of the caudal peduncle);

HL head length (from the tip of the upper jaw to the posteriormost point of the operculum);

HD head depth at nape;

HW head width (widest distance between the two gill covers);

SNL snout length (from tip of snout to the anterior corner of the eye);

ED eye diameter (diameter of the exposed portion of the eyeball);

IOD interorbital distance (minimum distance between the eyes);

IPND prenostril distance (the tip of the upper jaw to the anterior margin of the anterior nostril);

POND distance between posterior nostrils (the shortest distance between posterior nostrils);

UJL upper jaw length (from the tip of the upper jaw (the symphysis of the premaxilla) to the corner of the mouth);

LJL lower jaw length (from the symphysis of the dentary to the corner of the mouth);

MW mouth width (the distance between the two corners of the mouth);

RBL rostral barbel length;

MBL maxillary barbel length;

FHL forehead horn length;

PFPVL distance from the pectoral-fin insertion to the ventral-fin origin; and

PVAFL distance from the insertion of the pelvic fin to the origin of the anal-fin.

We compared the morphological characters of the new species with literature data for 21 other species in the S. angularis and S. microphthalmus species groups (Table 3). We also examined the type and/or materials from the type-localities of S. angularis, S. bicornutus, S. hyalinus, S. rhinocerous, and S. zhenfengensis (Appendix 1). Principal component analyses (PCAs) of size-corrected measurements and simple bivariate scatterplots were used to explore and characterize the morphometric differences between the new species and S. rhinocerous and S. hyalinus. Mann–Whitney U tests were used to determine the significance of differences in morphometric characters between the new species and similar species, i.e., S. angularis, S. bicornutus, and S. rhinocerous. All statistical analyses were performed using SPSS 21.0 (SPSS, Inc., Chicago, IL, USA), and differences were considered statistically significant at P < 0.05. PCAs of morphological data were performed after logarithmic transformation and under conditions of no rotation. In addition, as reported by other researchers (Parsons and Jones 2000; Polaszek et al. 2010), canonical discriminant analysis (CDA, George and Paul 2010) was used to classify individuals into different groups, where a priori membership was determined based on specimens belonging to different species. All pre-processing of morphological data was performed in Microsoft Excel (Microsoft Corporation 2016).

Table 3.
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Comparison of the diagnostic features of the new species described here with those selected for the 21 species of the S. angularis and S. microphthalmus species groups within the genus Sinocyclocheilus. Grey shading indicates clear difference in character compared to that of Sinocyclocheilus longicornus sp. nov.

Species Horn length Horn shape: forked (2), single (1), absent or indistinct (0) Eyes: normal (2), reduced (1), absent (0) Dorsal-fin rays Pectoral-fin rays Anal-fin rays Pelvic-fin rays Lateral-line scales/pores Body scales Gill rakers Pelvic-fin rays reaches backward
S. longicornus sp. nov. Long 1 1/0 ii, 7 ii, 13 iii, 5 i, 7 38–49 Absent 9 Tips of the pelvic-fin rays without reaches to the anus
S. altishoulderus Absent 0 1 iv, 4–7 i, 16 iii, 3–5 i, 8 54–58 Body covered with thin scale 10–12 Tips of the pelvic-fin rays reaches to or beyond the anus
S. anatirostris Short 1 0 iii, 8 i, 12–13 iii, 6 i, 6–8 33–42 Absent 8–12 Tips of the pelvic-fin rays without reaches to the anus
S. angularis Short 1 1 iii, 7 i, 15–18 iii, 5 i, 8 37–39 Absent 7 Tips of the pelvic-fin rays without reaches to the anus
S. anshuiensis Short 1 0 iii, 7 i, 11–12 ii, 5 i, 7 34–38 Body covered with thin scale 14 Tips of the pelvic-fin rays without reaches to the anus
S. aquihornes Short 1 0 iii, 7 i, 9 ii, 5 i, 6 36 Absent 8 Tips of the pelvic-fin rays reaches to the anus
S. bicornutus Short 2 1/0 iii, 7 i, 13–15 iii, 5 i, 7–9 36–40 Body covered with thin scale 7–9 Tips of the pelvic-fin rays reaches to the anus
S. brevibarbatus Absent 0 2 iii, 7 i, 14–15 iii, 5 i, 8–9 49–51 Body covered with thin scale 8–9 Tips of the pelvic-fin rays without reaches to the anus
S. broadihornes Short 1 1 iii, 6–7 i, 12–13 ii, 5 i, 5–6 35–37 Absent 4–6 Tips of the pelvic-fin rays reaches to or beyond the anus
S. convexiforeheadus Short 1 0 iii, 7 i, 9 ii, 5 i, 6 / Absent / Tips of the pelvic-fin rays without reaches to the anus
S. flexuosdorsalis Short 1 1 iii, 8 i, 12–13 iii, 5 i, 7 37–41 Body covered with thin scale 10 Tip of the pelvic-fin beyond the anus
S. furcodorsalis Short 2 0 iii, 7 i, 14–15 ii, 5 i, 7 40–46 Body covered with thin scale 8–10 Tips of the pelvic-fin rays reaches to the anus
S. hyalinus Long 1 0 iii, 7 i, 12–13 iii, 5 ii, 6–7 35–37 Absent 7–9 Tips of the pelvic-fin rays reaches to the anus
S. jiuxuensis Absent 0 1 iii, 7 ii, 12–14 ii, 5 i, 8 47–49 Body covered with thin scale 7–9 Tips of the pelvic-fin rays without reaches to the anus
S. mashanensis Absent 0 2 iii, 7 i, 9–11 ii, 5 i, 7–8 47–50 Body covered with thin scale 7–9 Tips of the pelvic-fin rays reaches to the anus
S. microphthalmus Absent 0 1 iii, 8 i, 12 iii, 5 i, 7 48–57 Absent 10–12 Tips of the pelvic-fin rays reaches to the anus
S. rhinocerous Long 1 1 iii, 7 i, 12 iii, 5 i, 6 37–45 Absent 8 Tips of the pelvic-fin rays without reaches to the anus
S. simengensis Short 1 2 iii, 7 i, 13–15 ii, 5 i, 7 56–57 Body covered with thin scale 9–10 Tips of the pelvic-fin rays without reaches to the anus
S. tianlinensis Short 1 0 iii, 8 i, 12 iii, 5 i, 7 Absent Absent 10 Tips of the pelvic-fin rays nearly reaches to the anus
S. tianeensis Short 2 0 iii, 7 i, 9–11 ii, 5 i, 6 35–39 Body covered with thin scale 7–9 Tips of the pelvic-fin rays reaches to the anus
S. tileihornes Long 2 1 iii, 7 i, 12–14 iii, 5 ii, 6–7 35–37 Absent 6–8 Tips of the pelvic-fin rays reaches to the anus or to the origin of the anal fin rays
S. zhenfengensis Absent 0 2 iii, 6–7 i, 13–15 iii, 5 i, 7 36–41 Body covered with thin scale 7–9 Tips of the pelvic-fin rays nearly reaches to the anus

Results

Phylogenetic analyses and genetic divergence

ML and BI phylogenies were constructed based on two concatenated mitochondrial gene sequences, including 1140 bp Cyt b and 1380 bp ND4. The ML and the BI phylogenetic trees showed identical topology (Fig. 2). The monophyly of the genus Sinocyclocheilus was strongly supported by both phylogenetic analyses but the monophyly of the S. angularis and S. cyphotergous species groups was rejected (Fig. 2). In both analyses, the S. longicornus sp. nov. formed a highly supported clade (0.99 in BI and 96% in ML) with S. hyalinus and S. rhinocerous.

Figure 2. 

Phylogenetic tree based on mitochondrial Cyt b + ND4 genes. In this phylogenetic tree, ultrafast bootstrap supports (UBP) from ML analyses/Bayesian posterior probabilities (BPP) from BI analyses were noted beside nodes. The scale bar represents 0.07 nucleotide substitutions per site. The numbers at the tip of branches corresponds to the ID numbers in Table 2. Different colored rectangular and triangular boxes in addition to the nodes denote the different states of the presence of horn-like structures of species within the genus Sinocyclocheilus.

The smallest p-distances between S. longicornus sp. nov. and other species of Sinocyclocheilus were 6.0% in Cyt b (with S. rhinocerous) and 5.6% in ND4 (with S. bicornutus). These levels of divergence were similar to those between pairs of other recognized species. For example, the Cyt b p-distance was 2.4% between S. anatirostris and S. angularis, 3.4% between S. bicornutus and S. brevibarbatus, while the ND4 p-distance was 2.7% between S. anatirostris and S. angularis and 2.6% between S. bicornutus and S. anatirostris (Suppl. materials 2, 3).

Morphological analyses

Mann–Whitney U tests showed that the Sinocyclocheilus longicornus sp. nov. differed from S. angularis, S. bicornutus, and S. rhinocerous in several morphological characters (Table 4). This was specially most obvious comparing S. longicornus sp. nov. and S. rhinocerous, in wihich 87% of the morphometric characters were significantly different (p = 0.00–0.03) (Table 3). Based on PCA of the morphological data, two principal component factors with eigenvalues greater than two were extracted. These accounted for a total of 89.86% of the total variation (Suppl. material 4). The first principal component (PC1) accounted for 83.37% of the variation and was positively correlated with all variables (eigenvalue = 27.22), thus reflecting the morphological differences between S. longicornus sp. nov. and similar species. The second principal component (PC2) accounted for 4.85% of the variation and was dominated by the length of the lower jaw (LJL), length of the upper jaw (UJL), and length of the head (HL) (eigenvalue = 0.44). On the two-dimensional plots of PC1 and PC2, S. longicornus sp. nov. can be clearly distinguished from S. angularis, S. rhinocerous, and S. hyalinus, and can be almost separated from S. angularis (Fig. 3A). A total of 29 characters were loaded on the PC 1 axis and were mainly influenced by body length, head, and fin ray characteristics (Suppl. material 4). CDA correctly classified 100% of the individuals in the initial grouping case for the four sample groups (N = 36). Canonical axes (CAN) 1–3 explained 59.8%, 30.6%, and 9.6% of the total variation, respectively (Fig. 3B; Suppl. material 5). Therefore, based on PCA and CDA, the 15 specimens of S. longicornus sp. nov. regions in the space of morphological characters compared to four similar species.

Table 4.
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Morphological comparison of Sinocyclocheilus longicornus sp. nov. (SL), S. angularis (SA), S. bicornutus (SB), S. rhinocerous (SR), S. zhenfengensis (SZ), and S. hyalinus. All units in mm. P-values are at 95% significance. Morphometric characters are explained in the methods section.

Measurements S. longicornus sp. nov. (N = 15) S. angularis (N = 7) S. bicornutus (N = 2) S. rhinocerous (N = 11) S. zhenfengensis (N = 8) S. hyalinus (N = 1) P-value from Mann-Whitney U test
Range Mean ± SD Range Mean ± SD Range Mean ± SD Range Mean ± SD Range Mean ± SD Range SL vs. SA SL vs. SB SL vs. SR SL vs. SZ
TL 104.8–145.8 123.3 ± 11.3 93.8–133.1 118.7 ± 13.9 157.8–163.1 160.5 ± 3.7 60.8–107.3 76.5 ± 12.3 71.73–138.4 100.9 ± 20.9 98.9 0.731 0.015 0.000 0.013
SL 84.3–116.4 99.8 ± 9.1 76.5–106.8 96.4 ± 11.0 123.1–128.4 125.8 ± 3.7 49.1–91.1 63.2 ± 11.2 56.78–114.1 81.2 ± 17.2 80.2 0.783 0.015 0.000 0.008
BD 23.9–37.4 30.9 ± 3.7 23.8–33.5 29.2 ± 3.8 29.2–33.6 31.4 ± 3.1 11.9–23.4 16.0 ± 3.2 19.1–35.3 24.9 ± 5.6 18.8 0.581 0.824 0.000 0.008
PL 45.3–64.5 53.4 ± 5.1 41.9–58.9 51.7 ± 5.9 66.5–68.2 67.4 ± 1.2 28.5–52.2 35.4 ± 6.5 35.9–59.5 47.0 ± 7.9 47.6 0.783 0.015 0.000 0.056
DFL 12.1–17.3 14.2 ± 1.7 12.6–15.6 14.2 ± 1.3 16.3–24.1 20.2 ± 5.5 6.9–13.8 9.1 ± 1.9 8.6–16.9 11.9 ± 2.7 12.8 0.837 0.059 0.000 0.023
DBL 10.9–24.6 19.8 ± 3.0 14.7–23.2 20.4 ± 2.9 25.6–29.6 27.6 ± 2.8 10.7–17.6 14.0 ± 2.2 13.3–27.5 17.8 ± 5.0 16.6 0.447 0.015 0.000 0.115
PAL 58.1–83.6 70.6 ± 7.4 53.9–78.9 70.0 ± 9.0 89.4–93.9 91.7 ± 3.2 14.6–64.3 41.3 ± 11.9 50.1–81.6 62.5 ± 11.8 59.2 1.000 0.015 0.000 0.101
ABL 6.9–11.8 8.9 ± 1.3 7.3–9.3 8.4 ± 0.7 9.9–12.2 11.1 ± 1.6 4.2–9.3 6.0 ± 1.5 5.7–10.1 7.7 ± 1.5 9.8 0.581 0.088 0.001 0.076
AFL 14.9–21.5 18.1 ± 1.8 12.8–17.6 15.5 ± 1.8 22.5–24.7 23.6 ± 1.6 8.6–15.9 11.5 ± 1.8 11.3–17.77 14.2 ± 2.2 13.9 0.014 0.015 0.000 0.001
PPTL 26.4–36.4 30.8 ± 2.8 22.7–33.1 29.1 ± 3.6 38.8–39.2 39.0 ± 0.3 16.6–32.8 22.4 ± 4.3 20.1–33.73 25.9 ± 5.1 29.6 0.407 0.015 0.001 0.040
PTBL 2.5–4.6 3.8 ± 0.6 3.3–5.1 4.3 ± 0.5 6.5–6.5 6.5 ± 0.0 1.5–3.3 2.2 ± 0.5 2.7–5.1 3.9 ± 0.8 2.7 0.106 0.015 0.000 0.776
PTFL 17.9–30.8 23.7 ± 3.1 15.7–22.8 20.9 ± 2.5 27.5–30.9 29.2 ± 2.4 10.9–21.2 13.5 ± 2.8 13.8–24.78 18.8 ± 4.1 18.0 0.047 0.059 0.000 0.016
PPVL 41.9–61.8 50.8 ± 5.1 38.5–56.4 50.4 ± 6.0 66.3–66.7 66.5 ± 0.3 23.6–47.7 31.9 ± 6.4 36.3–62.1 46.1 ± 9.9 46.3 0.837 0.015 0.000 0.149
PVBL 3.1–5.6 4.2 ± 0.8 3.6–5.6 4.6 ± 0.7 5.1–5.9 5.5 ± 0.6 1.7–4.5 2.7 ± 0.8 2.5–5.3 4.0 ± 1.0 2.9 0.267 0.059 0.001 0.636
PVFL 12.9–46.8 17.6 ± 8.2 12.4–15.1 14.0 ± 0.9 19.2–22.6 20.9 ± 2.4 7.1–14.3 10.3 ± 2.2 11.8–16.83 14.1 ± 2.2 11.5 0.014 0.059 0.000 0.131
CPL 13.6–25.3 21.0 ± 3.7 12.3–22 18.6 ± 3.9 20.1–22.6 21.4 ± 1.8 9.6–16.7 12.6 ± 2.2 14.5–22.01 17.6 ± 2.5 14.5 0.142 1.000 0.000 0.034
CPD 8.9–13.1 11.2 ± 1.2 8.8–13.1 11.7 ± 1.5 10.6–13.4 12.0 ± 2.0 3.7–8.3 6.1 ± 1.3 7.8–12.6 10.1 ± 1.8 5.5 0.368 0.529 0.000 0.149
HL 24.3–34.6 28.7 ± 3.1 22.7–32.1 27.6 ± 3.4 38.1–39.6 38.9 ± 1.1 16.1–30.9 20.7 ± 4.0 19.8–34.8 26.1 ± 4.8 27.7 0.680 0.015 0.001 0.190
HD 14.7–22.6 17.9 ± 2.3 12.7–17.9 15.7 ± 1.8 19.2–26.9 23.1 ± 5.4 7.9–15.6 10.6 ± 2.2 11.9–19.85 15.6 ± 2.7 16 0.047 0.176 0.000 0.040
HW 11.6–17.2 14.0 ± 1.8 10.9–14.2 13.0 ± 1.3 17.4–21.2 19.3 ± 2.7 6.7–12.4 8.6 ± 1.8 9.5–17.2 13.3 ± 2.4 11.5 0.380 0.015 0.000 0.506
SNL 10.5–15.4 12.4 ± 1.5 8.5–12.6 11.3 ± 1.5 13.4–16.1 14.8 ± 1.9 6.1–11.7 8.3 ± 1.6 7.2–14.2 9.9 ± 2.0 12.9 0.332 0.176 0.000 0.001
ED 0–1.6 1.1 ± 0.5 1.5–2.6 1.9 ± 0.4 2.2–3.5 2.9 ± 0.9 0.6–4.1 1.3 ± 1.0 2.1–2.84 2.3 ± 0.2 0 0.000 0.015 0.291 0.000
IOD 5.5–8.6 7.0 ± 0.9 7.2–8.7 7.9 ± 0.6 6.2–7.8 7.0 ± 1.1 3.2–7.4 4.3 ± 1.3 5.9–9.28 7.0 ± 1.2 / 0.056 1.000 0.000 0.591
IPND 2.9–4.7 3.9 ± 0.6 3.1–4.8 4.0 ± 0.6 4.8–7.2 6.0 ± 1.7 1.3–3.3 2.1 ± 0.7 3.8–6.9 4.8 ± 0.9 3.9 0.783 0.015 0.000 0.013
POND 4.3–6.6 5.5 ± 0.6 4.2–5.9 5.0 ± 0.6 6.5–7.1 6.8 ± 0.4 3.1–5.9 4.1 ± 0.8 3.9–6.66 5.1 ± 1.1 / 0.106 0.029 0.000 0.213
UJL 4.2–6.9 5.3 ± 0.7 4.8–7.6 6.2 ± 1.2 8.5–8.5 8.5 ± 0.0 3.5–6.2 4.6 ± 0.8 3.8–7.27 5.4 ± 1.1 6.7 0.123 0.015 0.028 0.925
LJL 3.2–5.6 4.5 ± 0.6 3.9–6.3 5.3 ± 0.9 7.5–7.6 7.6 ± 0.1 3.4–6.2 4.4 ± 0.8 3.3–5.6 4.6 ± 0.9 5.1 0.039 0.015 0.367 0.825
MW 4.6–7.9 6.1 ± 1.0 4.2–7.4 6.1 ± 1.2 6.8–9.7 8.3 ± 2.1 2.5–5.8 3.6 ± 1.0 4.5–8.49 6.8 ± 1.3 5.9 1.000 0.176 0.000 0.169
RBL 10.8–19.7 15.5 ± 2.5 7.8–15.1 12.2 ± 2.4 21.3–22.2 21.8 ± 0.6 2.9–7.9 5.9 ± 1.8 8.9–15.3 11.9 ± 2.2 3.8 0.011 0.015 0.000 0.003
MBL 10.1–18.3 14.2 ± 2.5 7.2–14.7 11.1 ± 2.5 22.4–23.1 22.8 ± 0.5 2.6–7.9 6.0 ± 1.9 8.5–14.1 11.9 ± 1.7 3.3 0.014 0.015 0.000 0.034
FHL 12.5–18.2 14.7 ± 1.5 8.4–13.4 10.6 ± 1.9 13.2–13.3 13.3 ± 0.1 7.0–13.6 9.4 ± 2.1 0–0 0.0 ± 0.0 12.9 0.000 0.059 0.000 0.000
PFPVL 15.3–24.5 19.1 ± 2.3 14.3–22.8 18.6 ± 3.0 21.3–22.6 22.0 ± 0.9 7.1–14.3 9.5 ± 2.2 13.7–28.6 18.1 ± 4.9 12.4 0.680 0.088 0.000 0.190
PVAFL 13.2–22.9 18.6 ± 2.8 14.1–22.8 18.8 ± 3.0 21.8–23.3 22.6 ± 1.1 7.0–14.3 9.8 ± 2.1 12.4–19.9 15.2 ± 2.7 12.6 0.891 0.059 0.000 0.013
SL/TL 0.79–0.83 0.81 ± 0.01 0.80–0.83 0.81 ± 0.01 0.78–0.79 0.78 ± 0.01 0.80–0.85 0.82 ± 0.02 0.79–0.82 0.80 ± 0.01 0.81 0.332 0.015 0.266 0.325
SL/BD 2.98–3.66 3.24 ± 0.19 3.18–3.60 3.31 ± 0.15 3.82–4.22 4.02 ± 0.28 3.76–4.59 3.96 ± 0.24 1.95–3.97 3.34 ± 0.61 4.27 0.267 0.015 0.000 0.056
SL/HL 3.12–3.70 3.49 ± 0.14 3.33–3.72 3.50 ± 0.14 3.23–3.24 3.24 ± 0.01 2.93–3.17 3.06 ± 0.08 1.86–3.52 3.14 ± 0.53 2.90 0.945 0.059 0.000 0.003
SL/CPL 4.18–6.72 4.85 ± 0.69 4.83–6.66 5.31 ± 0.78 5.68–6.12 5.90 ± 0.31 4.28–5.72 5.05 ± 0.50 2.58–5.88 4.67 ± 0.99 5.53 0.032 0.088 0.238 0.776
SL/CPD 8.04–9.84 8.95 ± 0.63 7.69–8.69 8.25 ± 0.36 9.58–11.61 10.60 ± 1.44 8.62–13.27 10.61 ± 1.42 4.59–9.15 8.14 ± 1.49 14.58 0.056 0.059 0.003 0.131
SL/PL 1.77–2.00 1.87 ± 0.06 1.78–1.98 1.87 ± 0.07 1.85–1.88 1.87 ± 0.02 1.72–1.87 1.79 ± 0.04 1.06–1.94 1.74 ± 0.28 1.68 0.783 1.000 0.001 0.213
SL/PPTL 3.06–3.46 3.25 ± 0.12 3.19–3.43 3.32 ± 0.09 3.14–3.31 3.22 ± 0.12 2.77–2.96 2.83 ± 0.06 1.68–3.80 3.20 ± 0.64 2.71 0.185 1.000 0.000 0.169
SL/PPVL 1.87–2.06 1.97 ± 0.05 1.83–1.99 1.92 ± 0.06 1.86–1.93 1.89 ± 0.05 1.91–2.08 1.99 ± 0.05 0.96–1.97 1.80 ± 0.34 1.73 0.066 0.088 0.184 0.028
SL/PAL 1.36–1.48 1.42 ± 0.04 1.32–1.42 1.38 ± 0.03 1.31–1.44 1.37 ± 0.09 1.37–3.99 1.68 ± 0.77 0.74–1.46 1.32 ± 0.23 1.35 0.106 0.441 0.023 0.238
CPL/CPD 1.25–2.35 1.88 ± 0.27 1.15–1.78 1.58 ± 0.22 1.69–1.90 1.79 ± 0.15 1.72–2.71 2.11 ± 0.30 1.45–1.89 1.76 ± 0.17 2.64 0.011 0.618 0.066 0.149
HL/SNL 2.04–2.55 2.32 ± 0.13 2.25–2.67 2.45 ± 0.14 2.46–2.84 2.65 ± 0.27 2.31–2.78 2.51 ± 0.15 2.27–3.54 2.67 ± 0.39 2.15 0.066 0.059 0.008 0.002
HL/HW 1.79–2.34 2.06 ± 0.14 2.04–2.26 2.11 ± 0.10 1.87–2.19 2.03 ± 0.23 2.19–2.67 2.43 ± 0.16 1.82–2.08 1.97 ± 0.08 2.41 0.581 0.824 0.000 0.131
HL/HD 1.43–1.78 1.61 ± 0.10 1.60–1.92 1.76 ± 0.10 1.47–1.98 1.73 ± 0.36 1.77–2.16 1.96 ± 0.11 1.54–1.85 1.67 ± 0.09 1.73 0.007 0.824 0.000 0.149
HL/RBL 1.47–2.46 1.88 ± 0.27 1.88–2.91 2.30 ± 0.37 1.78–1.79 1.79 ± 0.00 2.34–5.55 3.79 ± 1.04 1.90–2.41 2.20 ± 0.18 7.29 0.017 0.529 0.000 0.007
HL/MBL 1.77–2.75 2.05 ± 0.26 1.93–3.15 2.56 ± 0.47 1.65–1.77 1.71 ± 0.08 2.31–6.19 3.82 ± 1.32 1.92–2.59 2.20 ± 0.24 8.39 0.007 0.015 0.000 0.131
HL/IPND 6.20–9.59 7.37 ± 0.88 5.97–10.35 7.06 ± 1.51 5.50–7.94 6.72 ± 1.72 5.73–14.77 10.45 ± 2.55 4.98–6.51 5.47 ± 0.53 7.10 0.210 0.529 0.012 0.000
HL/POND 2.07–3.06 2.56 ± 0.25 2.41–2.96 2.63 ± 0.21 2.45–3.26 2.86 ± 0.57 1.84–2.45 2.10 ± 0.19 2.39–2.88 2.65 ± 0.20 / 0.630 0.618 0.000 0.466
PTFL/PFPVL 1.09–1.40 1.24 ± 0.08 1.00–1.27 1.13 ± 0.11 1.22–1.45 1.33 ± 0.17 1.20–1.62 1.43 ± 0.13 0.81–1.71 1.07 ± 0.29 1.45 0.066 0.368 0.003 0.007
PVFL/PVAFL 0.74–2.14 0.94 ± 0.34 0.61–0.88 0.76 ± 0.10 0.82–1.04 0.93 ± 0.15 0.72–1.40 1.06 ± 0.17 0.79–1.34 0.95 ± 0.18 0.91 0.056 0.721 0.021 0.392
HW/IOD 1.68–2.64 2.01 ± 0.29 1.51–1.86 1.66 ± 0.15 2.72–2.81 2.76 ± 0.06 1.04–2.53 2.07 ± 0.39 1.61–2.07 1.89 ± 0.16 / 0.004 0.015 0.186 0.728
Figure 3. 

Plots of principal component analysis, and canonical discriminant analysis scores of Sinocyclocheilus longicornus sp. nov., S. angularis, S. rhinocerous, and S. hyalinus based on morphological characters.

Taxonomic account

Sinocyclocheilus longicornus Luo, Xu, Wu, Zhou & Zhou, sp. nov.

https://zoobank.org/F447A6B3-1304-4734-BC57-B46E32034451
Figs 4, 5, Suppl. material 1

Material examined

Holotype. GZNU20210503002, 135.9 mm total length (TL), 109.8 mm standard length (SL), adult male collected by Jia-Jun Zhou and Tao Luo on May 6, 2021 in Hongguo Town, Panzhou City, Guizhou Province, China (25.6576°N, 104.4044°E; ca. 1852 m a.s.l.). Paratypes. Fourteen adult male specimens from the same locality as the holotype: GZNU20210503001, GZNU20210503003–03013, GZNU20210503015–503016, 84.3–116.4 mm SL, collected by Tao Luo, Jia-Jun Zhou, and Xing-Liang Wang on May 6, 2021.

Diagnosis

Sinocyclocheilus longicornus sp. nov. can be distinguished from all other congeners by the following combination of characters: (1) having a single, relatively long horn-like structure on the back of the head; (2) body scaleless, albinotic body without pigmentation; (3) reduced eyes; (4) dorsal-fin rays, ii, 7; (5) pectoral-fin rays, i, 13; (6) anal-fin rays, iii, 5; (7) pelvic-fin rays, i, 7; (8) lateral line pores 38–49; (9) gill rakers well developed, 9 on first gill arch; (10) tip of the pelvic-fin rays not reaching the anus when pelvic-fin rays extended backward.

Description

Body moderately elongate and compressed. Dorsal profile convex from nape to dorsal-fin; greatest body depth at dorsal-fin insertion; ventral profile slightly concave, tapering gradually toward the caudal-fin; greatest body depth slightly anterior to dorsal-fin insertion.

Head short, compressed laterally, length longer than maximum head width, depth longer than maximum head width. large and long anterior horn-like structure present on back of head not forked at tip, at about 45° angle to horizontal and curved downward at tip. Reduced eyes present in upper half of head; eye diameter less than interorbital distance; interorbital distance larger than distance between posterior nostrils. Snout short, U-shaped, and projecting beyond lower jaw in dorsal view, less than half head length.

Mouth subterminal, with slightly projecting upper jaw. Two pairs of nostrils, anterior and posterior nostrils neighboring, nares at 1/3 between snout tip and anterior margin of eye; anterior nares possessing an anterior rim with a posterior fleshy flap forming a half-tube. Two pairs of barbels; rostral barbels long, insertion of rostral barbel in front of anterior nostril, not reaching anterior edge of operculum when rostral bent backward; maxillary barbel slightly shorter compared to rostral barbel, tip surpassing eye but not reaching anterior edge of operculum when bent backward. Gill opening large, opercular membranes connected at isthmus, gill rakers well developed, nine on first gill arch. Pharyngeal teeth in three rows with counts of 2, 3, 5–5, 3, 2; pharyngeal teeth strong and well developed, with curved and pointed tips.

Dorsal fin with two unbranched and seven branched rays; last unbranched dorsal-fin ray hard at base, softening toward tip, with strong serrations along posterior edge; distal margin slightly concave, origin slightly anterior to, or superior to, pelvic-fin insertion and closer to caudal-fin base than to snout tip. Pectoral fin long with one unbranched and 13 branched rays; tip of depressed fin extending about midway between pectoral fin and pelvic-fin insertion; extending from posterior to pelvic-fin insertion and reaching to 35.44% of pelvic-fin length. Pelvic-fin long with one unbranched and seven branched rays, insertion slightly in front of dorsal-fin insertion, tip of the pelvic-fin rays not reaching the anus when pelvic-fin rays extended backward. Anus closer to anal-fin insertion than pelvic-fin insertion; anal fin with three unbranched and five branched rays; tip of anal-fin not reaching to caudal-fin base. Caudal fin with 17 branched rays and 14 unbranched rays, strongly forked; upper and lower lobes broadly pointed, unequal in length and shape.

Lateral line complete, slightly straight, curved upward at the anus position, originating from posterior margin of operculum and extending to end of caudal peduncle. Body scaleless, lateral line pores 38–49.

Coloration of holotype. In life, body overall white, slightly pink posterior to dorsal fin; barbels and gills red (Fig. 5); with white granular nuptial organs on dorsal surfaces of horn-like structure on back of head and snout (Fig. 5). In 10% formalin, body overall light yellow; posterior part of operculum and all fins partially transparent (Fig. 4).

Figure 4. 

Lateral view of adult male holotype GZNU20210503002 of Sinocyclocheilus longicornus sp. nov. in preservative. A left side view B right side view.

Figure 5. 

Live adult male paratype of Sinocyclocheilus longicornus sp. nov.

Comparative morphology

Sinocyclocheilus longicornus sp. nov. is assigned to the Sinocyclocheilus angularis species group based on phylogenetic analysis and the shared presence of the anterior horn-like structure on the back of the head (Fig. 2; Zhao and Zhang 2009). Comparative data of Sinocyclocheilus longicornus sp. nov. with the 21 recognized species in the S. angularis and S. microphthalmus species groups are given in Table 3.

Sinocyclocheilus longicornus sp. nov. differs from 55 species in the S. cyphotergous, S. jii, and S. tingi species groups by the presence of a horn-like structure on the back of the head (vs. absent). From the 21 species in the S. angularis and S. microphthalmus species groups, Sinocyclocheilus longicornus sp. nov. can be distinguished from S. altishoulderus, S. jiuxuensis, S. brevibarbatus, S. microphthalmus, S. zhenfengensis, and S. mashanensis by having a long horn-like structure on the back of the head (vs. absent or indistinct), further distinguished from S. brevibarbatus, S. mashanensis, S. simengensis, S. zhenfengensis by reduced eyes (vs. normal); differs from S. furcodorsalis, S. hyalinus, S. anatirostris, S. aquihornes, S. tianlinensis, S. anshuiensis, S. convexiforeheadus, and S. tianeensis by reduced eyes (vs. absent).

Sinocyclocheilus longicornus sp. nov. differs from S. angularis by having a relatively long horn-like structure (14.7 ± 1.5 mm vs. 10.6 ± 1.9 mm; p-value < 0.01, Table 4), long rostral and maxillary barbels (p-value < 0.05, Table 4), two unbranched dorsal-fin rays (vs. three), pectoral-fin rays (ii, 13 vs. i, 15–18), pelvic-fin rays (i, 7 vs. i, 8–10), gill rakers (nine vs. seven), and body scaleless (vs. body covered with thin scales); from S. bicornutus by single horn-like structure on the back of the head (vs. forked), dorsal fin rays (ii, 7 vs. iii, 7), pectoral-fin rays (ii, 13 vs. i, 15–18), body scaleless (vs. body covered with thin scales), and tip of the pelvic-fin rays not reaching the anus when pelvic-fin rays extended backward (vs. beyond the anus); from S. broadihornes and S. simengensis by dorsal fin rays (ii, 7 vs. iii, 6–7), anal-fin rays (iii, 5 vs. ii, 5), and lateral line pores (38–49 vs. 35–37 in S. broadihornes and 56–57 in S. simengensis); from S. flexuosdorsalis by having a relatively long horn-like structure (vs. short), dorsal-fin rays (ii, 7 vs. iii, 8), pectoral fin rays (ii, 13 vs. i, 12–13), snout length to standard length ratio is small (12.4% vs.14.4%), body scaleless (vs. body covered with scales), and tip of the pelvic-fin rays not reaching the anus when pelvic-fin rays extended backward (vs. beyond the anus); from S. tileihornesy by dorsal-fin rays (ii, 7 vs. iii, 7), anal-fin rays (iii, 5 vs. ii, 5), pelvic-fin rays (i, 7 vs. ii, 6–7), pectoral fin rays (ii, 13 vs. i, 12–15), pelvic fin rays (i, 7 vs. i, 6), lateral line pores (38–49 vs. 35–37), gill rakers (9 vs. 6–8), and tip of the pelvic-fin rays not reaching the anus when pelvic-fin rays extended backward (vs. beyond the anus).

Sinocyclocheilus longihornes can be morphologically distinguished from its close relatives S. rhinocerous and S. hyalinus. Sinocyclocheilus longicornus sp. nov. differs from S. hyalinus by eyes small and degenerate (vs. absent), dorsal-fin rays (ii, 7 vs. iii, 7), pelvic-fin rays (i, 7 vs. ii, 6–7), lateral line pores (39–45 vs. 35–37), and tip of the pelvic-fin rays not reaching the anus when pelvic-fin rays extended backward (vs. beyond the anus). Sinocyclocheilus longicornus sp. nov. differs from S. rhinocerous by having a large body size (123.3 ± 11.3 mm vs. 76.5 ± 12.3 mm; p-e = 0.00, Table 3), long horn-like structure (14.7 ± 1.5 mm vs. 9.4 ± 2.1 mm; p = 0.00, Table 3), dorsal-fin rays (ii, 7 vs. iii, 7), pectoral-fin rays (ii, 13 vs. i, 12), pelvic-fin rays (i, 7 vs. i, 6), gill rakers (9 vs. 8), and a relatively long, single horn-like structure on the back of the head (14.7 ± 1.5 mm vs. 9.4 ± 2.1 mm; p < 0.01, Table 4). In addition, except for morphological characteristics (eye diameter, mouth width) and some ratios, such as the SL to TL ratio, SL to CPL ratio, SL to PPVL ratio, and HW to IOD ratio, the remaining morphometric values and ratios of Sinocyclocheilus longicornus sp. nov. are significantly greater than those of S. rhinocerous.

Geographical distribution and habitat

Sinocyclocheilus longicornus sp. nov. is only known from the type locality, a vertical cave some distance from Hongguo Town, Panzhou city, Guizhou, China at an elevation of 2276 m. There was no light inside the cave. Individuals of S. longicornus sp. nov. were located in a small pool ~ 25 m from the cave entrance. The pool was ~ 1.8 m wide and 80 cm deep, with a water temperature of ~ 16 °C at collection time and a water pH of 7.4. The 15 specimens collected on 3 May 2021 were all adult males. Therefore, we believe that the breeding period started from mid-April. Within this cave, Sinocyclocheilus longicornus sp. nov. co-occurred with Triplophysa sp., and Sinocyclocheilus sp. Outside the cave, the arable land was farmed to produce maize, wheat, and potatoes.

Etymology

The specific epithet longicornus is an invariable noun in apposition, derived from the Latin words longus, meaning long, and cornu or cornus, meaning horn of the forehead, in reference to the presence of a long horn-like structure on the forehead of the species. We propose the English common name Long-Horned Golden-lined Fish and the Chinese common name Cháng Jiǎo Jīn Xiàn Bā (长角金线鲃).

Discussion

Morphological comparison and phylogenetic analysis support the generic assignment and and separate species status of Sinocyclocheilus longicornus sp. nov. The genetic differences between the new species and its close relatives, S. hyalinus and S. rhinocerous, were greater than the known genetic distances between other species (Suppl. materials 3, 4). Sinocyclocheilus longicornus sp. nov. the number of species of Sinocyclocheilus to 77, of which 13 species are recorded from Guizhou Province, China.

The genus Sinocyclocheilus is recognized as monophyletic, but there is no consensus on the classification of species groups (Zhao and Zhang 2009; Xiang 2014; Liu 2018; Mao et al. 2021, 2022; Wen et al. 2022). Initially, Sinocyclocheilus was divided into four species groups, S. jii, S. angularis, S. cyphotergous, and S. tingi, based on mitochondrial Cyt b and morphological differences (Zhao and Zhang 2009). Phylogenetic trees reconstructed using mitochondrial ND4 and Cyt b, mitochondrial genome, and restriction site–associated DNA sequencing supported monophyly of the S. jii and S. tingi species groups and rejected monophyly of the S. angularis and S. cyphotergous species groups (Xiang 2014; Liu 2018; Mao et al. 2021, 2022; Wen et al. 2022; this study). These studies proposed new classification schemes, such as two new clades (Clades E and F) from Mao et al. (2022) and a new species group (S. microphthalmus group) from Wen et al. (2022). Inconsistent topological differences may be related to molecular marker types, number of species and evolutionary models. For example, a phylogenetic tree reconstructed by Mao et al. (2021) for 49 species of Sinocyclocheilus using the GTR+I+G model for both mitochondrial ND4 and Cyt b rejected monophyly of the S. cyphotergous group. We reanalyzed their data for codon partitioning and found that the monophyly of both S. angularis and S. cyphotergous species groups was rejected. Different genes and different codons may have different evolutionary rates (Degnan and Rosenberg 2009), so the analysis may produce conflicting results when the same untested model is applied to different gene segments. Therefore, to resolve classification disagreements among species groups, the use of genomic data and a sufficient number of species is needed for future studies.

Variable or specialized morphological characters of Sinocyclocheilus are closely related to the orogeny producing dark cave environments (Yang et al. 2016; Mao et al. 2021, 2022; Wen et al. 2022). For example, horn-like structures (single or forked, long or short) or bulges on the back of the head, and degeneration or loss of eyes (Zhao and Zhang 2009). Sinocyclocheilus longicornus sp. nov. has a relatively long, unforked horn-like structure on the forehead, and small, degenerated eyes. It clustered with eight species of the S. angularis species group on the phylogenetic tree and could be divided into Clade I and Clade II. (Fig. 2). Long and short/indistinct horn-like structures are present in Clade I and Clade II, respectively (Fig. 2). Based on the present study and previous phylogenetic trees (Mao et al. 2021, 2022; Wen et al. 2022), we hypothesize that the evolution of the forehead horn may have occurred in at least two independent formations, one weakening event and one loss event (Fig. 2). As for the eye, no corresponding clade was found within the S. angularis species group, and variable eye phenotypes were also reported within S. bicornutus (in press), which may be related to the reduction of eye size during evolution or to the abundance and deprivation of food resources during growth and development, as well as related gene mutations (Ma et al. 2020; Mao et al. 2021).

Acknowledgements

This research was supported by the programs of the Strategic Priority Research Program B of the Chinese Academy of Sciences (CAS) (No. XDB31000000), the National Animal Collection Resource Center, China (No. 2005DKA21402), the Guizhou Normal University Academic Emerging Talent Fund Project (Qianshi Xin Miao [2021] 20), and the Postgraduate Education Innovation Programme of Guizhou Province (No. Qianjiaohe YJSKYJJ [2021] 091). We thank Gao-Kui Feng, Xing-Liang Wang, Ya-Li Wang, Wei Li, and Chang-Ting Lan for help with specimen collection. We thank LetPub (www.letpub.com) for its linguistic assistance during manuscript preparation.

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Appendix 1

Specimens examined

Sinocyclocheilus angularis (N = 7): China: Guizhou Province: Panzhou City: Baotian Town, (type locality): GZNU 20210505001–05004, GZNU 20210505006–05007, GZNU 0505001, collected by Tao Luo, Jiajun Zhou and Xingliang Wang on 5 May 2021. These specimens are stored at the Guizhou Normal University, Yunyan District, Guiyang City, Guizhou Province. China.

Sinocyclocheilus bicornutus (N = 2): China: Guizhou Province: Xingren City: Xiashan Town, Gaowu Village (type locality): GZNU 20210506001–06002, collected by Tao Luo, Jiajun Zhou and Xingliang Wang on 6 May 2021. These specimens are stored at the Guizhou Normal University, Yunyan District, Guiyang City, Guizhou Province, China.

Sinocyclocheilus hyalinus (N = 1): China: Yunnan Province: Luxi County: Alu Ancient Cave (type locality): KIZ 916001 (type locality). Currently preserved in Kunming Institute of Zoology, Chinese Academy of Sciences, China.

Sinocyclocheilus rhinocerous (N = 11): China: Yunnan Province: Luoping County: Huancheng Township, Xiaomingzhai Group (type locality): FWOQB199309001–09006, collected by Weixian Li and Jinneng Tao in September 1993;Yunnan Province: Shizong County: Wulong Township, Huaga Village (topotype locality): FWOQB20180322001–22005, collected by Hongfu Yang on 22 March 2018. Currently these specimens are stored by Yang Hongfu at the fisheries workstation in Qubei County, Yunnan Province, China.

Sinocyclocheilus zhenfengensis (N = 8): China: Guizhou Province: Zhenfeng County: Zhexiang Town, Shuangrufeng Scenic Area (type locality): GZNU20120701001(Holotype), GZNU20190707001–07003, GZNU20210619001–19004. These specimens are stored at the Guizhou Normal University, Yunyan District, Guiyang City, Guizhou Province, China.

Supplementary materials

Supplementary material 1 

Measurements of the adult specimens of Sinocyclocheilus longicornus sp. nov.

Cheng Xu, Tao Luo, Jia-Jun Zhou, Li Wu, Xin-Rui Zhao, Hong-Fu Yang, Ning Xiao, Jiang Zhou

Data type: table (word document).

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (53.71 kb)
Supplementary material 2 

Uncorrected p-distance (%) between 53 species of the genus Sinocyclocheilus based on mitochondrial Cyt b sequences

Cheng Xu, Tao Luo, Jia-Jun Zhou, Li Wu, Xin-Rui Zhao, Hong-Fu Yang, Ning Xiao, Jiang Zhou

Data type: table (excel document).

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (24.28 kb)
Supplementary material 3 

Uncorrected p-distance (%) between 52 species of the genus Sinocyclocheilus based on mitochondrial ND4 sequences

Cheng Xu, Tao Luo, Jia-Jun Zhou, Li Wu, Xin-Rui Zhao, Hong-Fu Yang, Ning Xiao, Jiang Zhou

Data type: table (excel document).

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (23.56 kb)
Supplementary material 4 

Variable loadings for principal components with Eigenvalues greater than 2, from morphometric characters corrected by SL

Cheng Xu, Tao Luo, Jia-Jun Zhou, Li Wu, Xin-Rui Zhao, Hong-Fu Yang, Ning Xiao, Jiang Zhou

Data type: table (word document).

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (13.66 kb)
Supplementary material 5 

Parameters in the canonical discriminant analysis (CDA)

Cheng Xu, Tao Luo, Jia-Jun Zhou, Li Wu, Xin-Rui Zhao, Hong-Fu Yang, Ning Xiao, Jiang Zhou

Data type: table (word document).

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (14.80 kb)
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