中国鳅属及其邻近属鱼类系统分类学研究

Cobitidae is the richest Euro-Asian family except Cyprinidae. The genus Cobitis Linnaeus, 1758, one of the largest in the family Cobitidae, are primary freshwater fishes occurring in nearly all major water systems of Eurasia and one species occurs in north-west Africa. In general, Cobitidae show comparably few morphological characters useful to diagnose the natural groups within the family and as a result, there is no consensus about the number of included genera and the valid name of some species. A traditional and recurrent morphological character used to define genera within Cobitidae is the secondary sexual dimorphism. Unfortunately, the presence of the character states of the sexual dimorphism is not always congruent with the current outline of genera as most character states are observed in more than one genus, while in several genera certain species lack an otherwise diagnostic character state. Therefore, the utility of the sexual dimorphism for delimitation of genera within Cobitidae need confirmation. Besides the confusion in the genus level, the taxonomic diversity of the genus Cobitis is also very difficult to be recognized. Because except the "morphological species", the genus Cobitis also include different forms "sibling species". The most complicated group of "sibling species" includes several diploid and polyploid forms with external morphology similar to that from the diploid bisexual species. They coexist and are also referred to as "complexes". These forms are virtually indistinguishable based on external characters. Several complementary methodologies, such as morphological comparison, karyotyping, mitochondrial and nuclear gene analyses, semi-quantitative PCR, the primary purposes of the present study are to revision of the taxonomic status of the genus Cobitis and it's relatives and the taxonomic position of the species of the genus Cobitis and it's relatives; determination of the two kinds diversity of the genus Cobitis in China, on the one hand a species diversity and on the other hand a diversity of hybrid biotypes; uncover the origin of the hybrid biotypes. Therefore, the ultimate aim of the present study is to provide basic data for the fauna research and biodiversity conservation.

鳅科鱼类在欧亚大陆淡水鱼类中占有重要的地位，鳅属及其邻近属是鳅科鱼类的重要组成部分，也是我国极其重要的淡水鱼类类群，在我国局限分布于红河以东。由于其个体小、形态相似、尤其是具有淡水鱼类中罕见的雌雄异形，其属种的分类和命名非常混乱。本项目采用形态学特征分析的方法，特别是在对其第二性征认识的基础上，结合DNA条形码技术、染色体组型分析和荧光半定量PCR技术，分析并重新界定鳅属及其邻近属鱼类属级阶元划分的鉴别依据，厘定其属种的有效种，完善或重新建立鳅属鱼类的分类系统；明确我国鳅属及其邻近属鱼类的物种多样性和分布，揭示其分布格局与东亚重大地质及环境事件的关联；探讨我国鳅属鱼类多倍体/复合体多样性、倍性及其起源演化过程，阐明其物种分化模式。为淡水鱼类的演化、生物地理学和生物多样性的保护提供科学依据。

鳅科（Cobitidae）在欧亚大陆淡水鱼类中占有重要的地位，鳅属（Cobitis）是鳅科鱼类中物种分化最为明显的一个类群，广泛分布于除青藏高原外的红河以东。鳅属及其邻近属鱼类由于长期适应相似的环境而产生趋同进化，其外部形态及内部骨骼特征都表现出较高的相似性，属种的分类和命名非常混乱。本项目采用形态学特征，结合线粒体基因Cytb、COI与核基因RAG1基因多位点的证据，重建了鳅属及其邻近属鱼类的分类系统；明确了我国鳅属及其邻近属鱼类的物种多样性和地理分布；探讨了鱼类多样性分布格局及其演化历史。.主要研究结果：.1..否定了益秀朝鲜属（Iksookimia）和动鳅属（Kichulchoia）的有效性，将其分别作为鳅属和后鳍鳅属（Niwaella）的同物异名；澄清了沙花鳅（Cobitis arenae）的分类地位；重新界定了鳅属及其邻近属鱼类属级阶元的划分。.2..由全国18个省区103个采样点采集到2000余尾标本，从中鉴定出鳅属鱼类44种，其中1新记录种（Cobitis choii），28新种；后鳍鳅属鱼类8种，其中5新种；双须鳅属（Bibarba）2种；泥鳅属（Misgurnus）3种；大鳞副泥鳅属（Paramisgurnus）1种，基本摸清了我国鳅属及其邻近属鱼类的物种多样性及地理分布。.3..基于线粒体基因和核基因重建了鳅科鱼类系统发育关系。结果表明，鳅科以云南的无量、哀牢山脉为界，分为南北两大分支。鳅属及其邻近属鱼类属于北方类群；双须鳅属位于北方类群的基部。泥鳅属鱼类在线粒体基因拓扑结构树中与鳅属鱼类相互嵌套，而在核基因拓扑结构树中形成单系群，说明鳅属鱼类与泥鳅属鱼类有基因交流。鳅属和后鳍鳅属均未构成单系，后鳍鳅属分为三支，分别为日本一支、韩国一支、中国一支。沙花鳅位于鳅属鱼类的基部，其他鳅属鱼类分成两大分支，分支I包含越南、中国、蒙古、俄罗斯、日本和韩国等东南亚和东亚的物种；分支II包含中国、日本、韩国、东亚、西亚、欧洲、北非的物种。鳅属鱼类起源于渐新世早期，是鳅科由东南亚和我国南方向北扩散过程中分化出来的类群。