中华绒螯蟹螯足长节产地差异的几何形态测量学研究

Geometric morphometric study on the origin difference of cheliped merus of Eriocheir sinensis

为掌握中华绒螯蟹螯外形精细结构的产地差异性,首次应用几何形态测量学方法,对长江中下游湖南省、安徽省、江苏省等7个产地蟹的螯足长节形态进行了比较研究。依据地标点法选取原则建立了螯足长节的14个特征点数据系统,并通过将其标准化,获得此7个产地蟹的平均型,再利用薄板样条分析和网格变形,对形态变异矢量进行了可视化分析。结果表明,与平均形比较,除无为野生蟹无明显的变化外,安徽省其他3个产地蟹长节形态有同趋势变化(即长节左下端向内缩小,长节内部凹陷点向左下端靠近);湖南、江苏3个产地蟹长节形态亦有同趋势变化(即长节左下端向外扩展,长节内部凹陷点向右上方向偏移)。此外,对上述标准化数据开展判别分析的结果更显示,7个产地雌、雄蟹个体间的判别准确率均可达100%。上述发现进一步证实了几何形态测量学法不仅在大至背甲,小至螯足长节的形态方面能有效把握中华绒螯蟹产地差异性,而且在非致死、致伤产地溯源技术研发上也极具潜力。

For revealing the origin difference on the morphological characteristics for a fine structure of cheli-ped merus,geometric morphological analysis was applied for the first time to comparatively investigate with E.sinensis crabs from seven different well-known geographical origins in Hunan Province,Anhui Province and Jiangsu Province in the middle and lower reaches of the Yangtze River.Based on landmark selection principle of corre-sponding computer software image processing,a 14-landmark system was established,and then,the average cheli-ped merus shape of the crabs from the seven origins was obtained by standardized operation.The morphological variation vector was further visualized by thin plate spline analysis and mesh deformation.In comparison with the average cheliped merus shape,although no significant variation was found for that of Wuwei wild population,sig-nificant differences were documented for those from other six origins,i.e.the morphology of the merus of crabs from three origins in Anhui Province showed the same trend.The left lower end of the merus was narrowed inward,and the internal depression point of the merus was close to the left lower end.The morphology of the merus of crabs from remaining 3 producing origins of Hunan and Jiangsu Provinces showed the same trend.The left lower end of the merus extended outward,and the internal depression points of the merus shifted to the right upper direction.The discriminant analysis of the above standardized data showed that the discriminant accuracy of female and male crabs could reach 100%.The above results innovatively confirm that the landmark approach has great potential for nonle-thal and non-wounded determination of the origin difference and traceability of E.sinensis crabs based on geometric morphology measurement by either large structure of carapace or fine structure/small part of cheliped merus.