基于地标点几何形态测量法区分不同水系野生中华绒螯蟹

为鉴别不同地理种群野生中华绒螯蟹(Eriocheir sinensis),运用基于地标点法的几何形态测量学方法研究长江、黄河、辽河、瓯江、闽江及图们江中野生中华绒螯蟹头胸甲的形态特征。主要步骤为先通过地标点法提取中华绒螯蟹头胸甲上特征点的坐标值,然后进行相对扭曲主成分分析和判别分析来区分 6 种群中华绒螯蟹头胸甲,最后利用薄板样条分析和网格变形将头胸甲形态变异矢量可视化。结果表明:(1)主成分散点图显示各群体之间虽有部分重叠,但大体可以形成较为集中的区域;(2)网格变形图显示各群体头胸甲的形态差异主要为额刺和侧刺长度;(3)逐步判别分析中各群体的判别准确率为 80%~96%,存在一定的错判风险;(4)聚类分析将 6 群体中华绒螯蟹聚为两支,其中长江、黄河、瓯江和闽江个体被聚为一支,辽河和图们江个体被聚为另外一支。综上,以头胸甲为研究对象的地标点几何形态测量法是区分不同水系野生中华绒螯蟹的有效手段,但仍需要结合传统形态学测量方及遗传结构分析加以辅助证实。

Landmark-based morphometric identification of wild Eriocheir sinensis with geographically different origins

With the development of statistical and computational technology, landmark-based morphometric analysis has widely been used for species classification and identification in recent years, but it has never been used to identify wild Eriocheir sinensis from geographically different basins. Therefore, this research was resized to identify different geographical populations of wild E. sinensis collected from the Tumen River (TR), Liao River (LR), Huang River (HR), Yangtze River (YR), Ou River (OR), and Min River (MR). Landmark-based geometric morphometrics analysis was used to compare the morphological characteristics of their carapaces. The main step was to extract coordinate values of landmark-based points on the carapace, and then perform the relative warp principal component analysis and discriminant analysis to distinguish the 6 wild populations, and finally visualize the morphological variation with thin plate spline analysis and grad distortion. The results showed that:(1) in principal component analysis, wild populations could be divided into 6 relatively independent groups by the first two principal components, though the plots slightly overlapped between different populations; (2) the grad distortion map showed that morphological differences of various populations were mainly manifested in the frontal and lateral spines of the carapace; (3) the discriminative accuracy of various populations in the stepwise discriminant analysis was 80%-96% with a certain risk of misjudgment; (4) cluster analysis showed that YR, HR, OR, and MR individuals clustered independently, whereas TR and LR individuals formed another distinct cluster, whether females or males. In summary, landmark-based morphometrics analysis is an effective means to distinguish wild E. sinensis from different basins, but it still needs to be confirmed by traditional morphometrics analysis and genetic analysis.