长江中下游鲤形目鱼类多样性发生与环境变化关系研究

The order Cypriniformes is the largest freshwater fish group in China and in the world, and it is also a representative group of Chinese rivers and plain ichthyofauna compound body. The speciation and distribution of the Cypriniformes fishes were severely affected by the environmental variations of freshwater habitats associated by the paleogeologic and paleoclimatic events. Based on the biodiversity of the Cypriniformes in the middle and lower reaches of Changjiang River, our proposal will focus on how the high species diversity of cypriniformes was developed during the evolutionary history of Cypriniformes diversification. The high extant species diversity of current organisms is usually attributed to the recent and rapid accumulation of species via high speciation rates or the gradual accumulation and/or preservation of species over time via low extinction rates. We estimated divergence times for the cypriniforme fishes using molecular clock-independent approaches, and tested a novel hypothesis of a diversification shift occurring within this group using topological and temporal methods. Our goals will be: (1) whether the evolutionary history of the Cypriniformes diversification (speciation-extinction) departs significantly from a constant rate model, (2) whether the Cyprinifomres has experienced rapid shifts in diversification rate during its evolutionary history, and (3) whether these data support temporal patterns of diversification consistent with the models of recent and rapid diversification or those of slow accumulation of diversity over time and/or preservation of ancient diversity.

长江中下游流域鲤形目鱼类是中国江河平原区系复合体中一个非常重要的代表类群，其物种的分化和分布受到了地质历史过程中古地质和古气候因素的强烈影响。本研究项目以区域性分布的鲤形目鱼类为研究对象，开展长江中下游鲤形目鱼类物种多样性发生的分子系统学研究，目的是为了探讨长江中下游流域鲤形目鱼类进化过程中的物种分化速率是否与恒定速率模型发生偏离；进一步明确鲤形目鱼类物种分化的时间和速率模型；在此研究基础之上，提出鲤形目鱼类的物种分化模式假说，即其物种分化时间模式是否符合生物多样性起源的近期快速物种累积模型或者长期逐步物种累积（保存）模型。通过长江中下游流域鲤形目鱼类物种多样性的起源和演化研究，为进一步全面认识长江流域水生生物多样性发生的时空格局奠定必要的基础。

长江中下游流域鲤形目鱼类是中国江河平原区系复合体中一个非常重要的代表类群，其物种的分化和分布受到了地质历史过程中古地质和古气候因素的强烈影响。本研究项目以区域性分布的鲤形目鱼类为研究对象，开展长江中下游鲤形目鱼类物种多样性发生的分子系统学研究，目的是为了探讨长江中下游流域鲤形目鱼类进化过程中的物种分化速率是否与恒定速率模型发生偏离；进一步明确鲤形目鱼类物种分化的时间和速率模型；在此研究基础之上，提出鲤形目鱼类的物种分化模式假说，即其物种分化时间模式是否符合生物多样性起源的近期快速物种累积模型或者长期逐步物种累积（保存）模型。通过长江中下游流域鲤形目鱼类物种多样性的起源和演化研究，为进一步全面认识长江流域水生生物多样性发生的时空格局奠定必要的基础。