Sinocyclocheilus sanxiaensis, a new blind fish from the Three Gorges of Yangtze River provides insights into speciation of Chinese cavefish
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摘要: 2019年2月,在湖北省秭归县郭家坝镇的长江三峡库区20米水深区域采集到一尾中国特有金线鲃属鱼类的全盲个体。从形态上这一个体极易与当前已知的其他金线鲃属鱼类区分开来,具体鉴别特征(大多为洞穴特征)如下:身体为正常纺锤形仅头背部起有轻微隆升,皮肤白化无色素,眼睛缺失,无头角状结构,两对须极短,嘴端位正常,脊椎骨数目为34,侧线鳞数目为41。从分子系统发育关系上而言该个体也与其他物种显著分化,与其姐妹近缘种隔离时间推算为0.55百万年。鉴于此,我们描述其为中国金线鲃属鱼类一新种,命名为三峡金线鲃(Sinocyclocheilussanxiaensis sp. nov. )。这一物种的发现将我国洞穴鱼类代表类群——金线鲃属鱼类已知的分布范围从北纬25°左右区域扩展到30°以北,也成为我国丰富的金线鲃属鱼类多样性中的第75个物种。鉴于长江三峡区域实际上蕴含着大量的喀斯特地形和发达的地下水网系统,而这一物种又属于典型洞穴鱼类,我们推测其可能由通向长江的某一条地下暗河而来。但是,其被发现于长江三峡库区水域的同时也带来了一系列未解之谜,如:它究竟是主动扩散还是被动迁移?总之,这一个体的发现和报道也鼓励我们对这一珍稀物种开展更多的野外生态调查和保护相关研究。Abstract: A blind fish of Sinocyclocheilus (Cypriniformes: Cyprinidae)was caught in open water in the Three Gorges (Sanxia)reservoir, at a depth of 20 m in the mainstream of YangtzeRiver in Zigui County, Hubei Province, China. This fish can beeasily distinguished from all other congeners by externalmorphological characteristics, and is estimated to havediverged from its sister group about 0.55 million years ago(Ma). The geologically well separated locality of this specieshas expanded the distribution of Sinocyclocheilus cavefishfrom around N25° (latitude) to above N30° . Herein, wedescribe this new species as Sinocyclocheilus sanxiaensis sp.nov ., and discuss the possible reasons why the speciesappears, surprisingly, in the Three Gorges reservoir.
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Key words:
- Cyprinidae /
- Sinocyclocheilus /
- cavefish /
- Three Gorges /
- Yangtze River
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