Morphological variation in three geographical populations of Estellarca olivacea
橄榄蚶三个地理群体的形态差异分析

Based on nine morphological characters of populations of Estellarca olivacea from Zhejiang Lingkun, Zhejiang Sanmen and Jiangsu Tongzhou, the morphological variations of three geographical populations were studied by means of multivariate morphometrics. The results of cluster analysis and principal component analysis revealed that the morphological characters of E. olivacea from Zhejiang Sanmen population and Zhejiang Lingkun population were similar to each other but were much more different from the character of Jiangsu Tongzhou population. In the principal component analysis, two principal components were constructed. The contributory ratios of the two principal components were 47.73% and 13.56% respectively and the cumulative contributory ratio was 61.29%. The shell protrusion or flat, shell thick and fore-and-aft shape determined the morphological variations of different geographical populations of E. olivacea, which were related with the water temperature and substrate.