Abstract:

In order to investigate the current status of germplasm resources of the freshwater snail B. purificata in China and provide quality germplasm resource for selection breeding, 249 samples were collected from wild populations in Jiangsu, Anhui, Shanghai, Shandong, Hunan, Guangxi, Jiangxi, Guizhou, Hubei, Zhejiang and Guangdong Provinces, 24 landmark points were set clockwise from the top of the shell for each individual of different groups and 15 semi-landmark points were set at equal intervals between the 11^th-12^th, 12-13^th, 13-14^th, 14-15^th, 15-11^th, 15-16^th landmarks. After all the landmarks and semi-landmarks setting finished, Procrustes fitting was performed and the outliers that exceeding upper quartile were removed. The missing value was checked by thin plate spline method. All the variations of the shape of all species were subjected to principal component analysis. Procrustes distance for different geographical groups were analysis by ANOVA and these distances were used for cluster analysis. The results showed that the main variation of shell morphology in the 11 geographic populations of the freshwater snail B. purificata was at the top of the shell and the upper edge of the aperture. The concentration of variation in morphological traits of different geographical populations was poor, and the 1^st principal component and 2^nd principal component could not significantly distinguish among different populations. The 11 populations could be divided into two major groups, the Yangtze River basin group and the south of Yangtze River group, and there were significant differences in the shape of the different populations, which may be related to the local habitats.

Key words: Bellamya purificata, geographic populations, geometric morphometric, landmark, semi-landmark