A morphological evaluation of Chrysaora chinensis of Peninsular Malaysia and distinguishing its populations using geometric morphometrics

摘要

The morphology of seven specimens of Chrysaora chinensis(Scyphomedusae,Semaestomae)obtained from four sites off the coast of Peninsular Malaysia was examined.Morphological characteristics of C.chinensis that encompasses structures such as the bell,tentacles,oral arms,stomach,manubrium,radial canals and gonads were described in detail.A total of 107 specimens that represented C.chinensis populations of four coastal areas of Peninsular Malaysia(East-Central,East-North,West-Central,and West-North)were also analysed for shape variation using geometric morphometric analysis.Procrustes superimposition,Principal Component Analysis(PCA)and Canonical Variate Analysis(CVA)were applied to the images of gastrovascular pouches of C.chinensis to extract the shape information.Independent contrasts were used for comparisons between shapes.There were no significant differences in shape variation between all the specimens based on the PCA results.However,CVA results showed shape variations between specimens taken from the four areas of Peninsular Malaysia,especially with higher magnitudes of Mahalanobis distances between the east and west coast areas,including between East-Central and East-North,but lower magnitudes were detected between the West-Central and West-North.