中国广西壮族自治区珠江流域鳅属一新种(英文)

A NEW SPECIES OF SPINED LOACH (OSTEICHTHYES,COBITIDAE) FROM THE PEARL RIVER,GUANGXI OF CHINA

记述采自中国广西壮族自治区邕江和郁江鳅属Cobitis1新种,南方鳅Cobitis australis sp.nov.。通过扩增其线粒体细胞色素b基因,与已知鳅属和益秀朝鲜鳅属Iksookimia物种进行遗传距离比较,并构建系统发育树,结合形态分析,确认其为1新种。南方鳅与本属其它种类的区别主要为:噶氏斑纹分界不明显(Gambetta's pigmentation pattern),斑纹具两性异形。雄性背部斑纹不规则,约17～20个,背鳍后斑纹融合为马鞍形;雌性背部斑纹约13个,背鳍前斑纹在体侧延伸为三角形。体侧中线11～13个不规则的"V"形或倒三角形斑纹,雄性头后4～5个小斑纹,雌性1～2个小斑纹。背部和体侧中线之间为形状和大小不规则的斑纹,雄性多于20个,该处斑纹与背部和体侧中线斑纹有融合;雌性少于20个,无融合。背鳍和尾鳍各具有4～5列点状条纹;雄性胸鳍第1根分枝鳍条基部的骨质突起(laminacir cularis)指状,第1根分支鳍条延长,胸鳍似旗状;体鳞较大,延长,卵圆形,鳞焦略大,基位;颏叶不发达,末端钝圆;须短,其长等于或略小于眼径。新种体色斑纹与益秀朝鲜鳅属种类相似,新种与益秀朝鲜鳅Iksookimia koreensis(Kim,1975)和斑纹益秀朝鲜鳅Iksookimia pumila(Kim et Lee,1987)的主要区别是,前者背鳍和尾鳍各具4～5条斑纹,背部斑纹和体侧中线斑纹不相连,体侧中线11～13个宽而短的倒三角形斑纹;益秀朝鲜鳅背鳍和尾鳍各具有3～4列条纹,体侧中线下13～14个窄而长的倒三角形斑纹;斑纹益秀朝鲜鳅背鳍和尾鳍各具有2～3列条纹,背部斑纹和体侧中线斑纹相连,两列斑纹之间斑块少于10个,体侧中线9～10个宽而长的条状或倒三角形斑纹。新种与盈德益秀朝鲜鳅Iksookimia yongdokensis Kimet Park,1997、休氏益秀朝鲜鳅Iksookimia hugowolfeldi Nalbant,1993和长身益秀朝鲜鳅Iksookimia longicor pus(Kim,Choi and Nalbant,1976)的主要区别是,前者骨质突起指状,后者骨质突起圆盘状。

A new species of spined loach, Cobitis australis sp. nov. is described from the Yujiang River and the Yongjiang River, a tributaries of the Pearl River basin, Guangxi, North China. Based on the sequences of mitochondrial cytochrome b gene, the interspecies relationships of Cobitis and Iksookimia were examined. The molecular study supported the species status of C. australis sp. nov. Cobitis australis is distinguished from its congeners by following combination： absence of the Gambetta’s pigmentation pattern; presence of sexual dimorph colour pattern with 17-20 irregular blotches on the dorsum in males and 13 oval blotches on the dorsum and the blotches extending trangle-shape on the dorsolateral sides in females; 11-13 irregular vertical elongated “v”-shape blotches along midlateral lines, and between them more then 20 vertical bars in males and less than 20 in females; 4-5 striations on the dorsal and caudal fins; one slender and long finger-shaped lamina circularis at the base of second ray of the male pectoral fins, the second ray is elongated nearly filamentous; scales vertical elongated and oval, with a large focal area; mental lobes of lower lip pointed not ending in a filiform tip; barbels short, barbel length equal to or shorter than eye diameter.