Dwell-Cave Fish Diversity In South And Southwest Guizhou

Guizhou province is located in the east of YunGui Plateau,is the slope area of YunGui Plateau to Guangxi and Hunan hilly region,belongs to the mountainous region of southwest China.Guizhou province is the central area of karst landform in Southern China,73% of the land is covered with carbonate rocks.It is the most important karst landform and cave distribution area of the world.In addition to the few counties,such as Chishui County and Congjiang County,all the other regions with carbonate rocks have cave distributed.The cavefish species of Guizhou province are very abundant,by now,20 species have been discovered and reported,Among of 12 species belong to Sinocyclocheilus(Cyprinidae),five species belong to Triplophysa(Nemacheilinae),two species belong to Oreonectes(Nemacheilinae),one species belong to Paracobitis(Nemacheilinae).In the study,we surveyed 11 Counties in South and Southwest Guizhou,collected approximately 300 specimens.The specimens are identified and analyzed by morphological and molecular phylogenetic methods.The main results of this study are as follows:1.According to morphological characteristics and molecular phylogenetic,13 pending species are identified.Among of seven species belong to Sinocyclocheilus,they are S.banzhaiensis,S.bianyangensis,S.boyaoensis,S.dongdaiensis,S.gaowuensis,S.jiuqianensis and S.maweiensis;five species belong to Triplophysa,they are T.bianyangensis,T.dongsaiensis,T.ganpaiensis,T.lewangensis and T.baotianensis;one species belong to Oreonectes,it is O.xiaoqikongensis.2.In the study,a total of 488 specimens are collected,including 302 from South Guizhou and 186 from Southwest Guizhou.The results of Simpson diversity index analysis show that the South region is 0.8258 and the Southwest region is 0.5708.3.Combined the mitochondrial gene sequencing results and the mitochondrial gene sequence obtain from GenBank,based on mitochondrial gene ND4,ND5 and Cytb,the molecular phylogenetic tree are structured using the maximum likelihood method(ML)and the bayesian method(BI).The results are as follows:(1)Triplophysa longibarbatus and Triplophysa jiarongensis are clustered with Oreonectes spp..The specimens are examined and neither of genus characteristics of Triplophysa.So,we advise to change their classification status to be Oreonectes longibarbatus and Oreonectes jiarongensis.(2)The results of phylogenetic tree show that,the cave species of Triplophysa which living int the Yangtze River and Pearl river,formed a monophyletic clade.They have different evolutionary direction.The Triplophysa species collected in this research,are all living in the karst cave,they clustered together with the other cave species,all of which are the cave-type of Triplophysa.(3)platycephalmus group and furcocaudalis group of Oreonectes spp.have not divided into two monophyletic branch,we advise continue to use the platycephalmus group and furcocaudalis group.To decide whether the furcocaudalis group should be promoted to the Troglonectes gen.nov.,more researchs of molecular phylogenetics are indispensable.4.Combined the mitochondrial gene sequencing of this study and the mitochondrial gene sequence obtain from GenBank and based on mitochondrial gene ND4 and Cytb,the molecular phylogenetic tree are structured using the maximum likelihood method(ML)and the bayesian method(BI).The results show that,13 Sinocyclocheilus species divided into four branchs,belong to three groups,the cyphotergous group including S.jiuqianensis,S.banzhaiensis,S.longibarbatus,S.hugeibarbus,S.boyaoensis,S.bianyangensis,S.cyphotergous,S.punctatus,S.multipunctatus and S.macrolepis.The angularis group including S.bicornutus and S.zhenfengensis.The tingi group including S.gaowuensis.5.The research results show that,there are 34 species of typical cavefish in South and Southwest Guizhou.Among of 20 species belong to Sinocyclocheilus,eight species belong to Triplophysa,five species belong to Oreonectes,one species belong to Paracobitis.