几何形态学对8种扇贝的形态分类的应用

几何形态学(morphometrics)是基于笛卡尔地标点的统计分析方法,主要运用广义普鲁克分析(GPA)、薄板样条分析(TPS)、主成分分析(PCA)、典型变量分析(CVA)等方法,定量的对形态变化进行识别,结果更为客观。本研究运用几何形态学方法对8种常见扇贝(栉孔扇贝Azumapecten farreri、虾夷盘扇贝Mizuhopecten yessoensis、海湾扇贝Argopecten irradians、平濑掌扇贝Volachlamys hirasei、北海道扇贝Swiftopecten swiftii、荣套扇贝Gloripallium pallium、华贵类栉孔扇贝Mimachlamys nobilis、美丽环扇贝Annachlamys striatula)间形态关系进行研究,运用界标点和半界标点对扇贝的壳盘和壳耳进行数字化标点,利用PCA、CVA、TPS方法,获得8种扇贝的形态差异并进一步分析,建立系统发育树。PCA和CVA分析结果表明可以通过几何形态测量学分析方法将8种扇贝基于形态差异进行有效区分。此外,结合TPS的分析结果,发现壳耳和壳盘在扇贝中具有种间规律性差异。通过其形态分异进行表型聚类,从结果可知:美丽环扇贝、虾夷盘扇贝和海湾扇贝距离较近,壳型有共同的特征:扇贝壳盘较椭圆,壳耳相对较小;荣套扇贝和华贵类栉孔扇贝距离较近,壳型有共同的特征:扇贝壳盘更扁平,前耳相对较大;北海道扇贝、平濑掌扇贝和栉孔扇贝与其他种类没有交集。在聚类过程中,华贵类栉孔扇贝和荣套扇贝有交集,10个标本混淆,其他标本均成功聚类,正确率为95.5%。

Application of geometric morphology to the morphological classification and phylogeny of eight of scallop species

Geometric morphology is a statistical analysis method based on Cartesian geodesic points, mainly using Generalized Procrustes Analysis (GPA), thin-plate spline (TPS), Principal Components Analysis (PCA), Canonical Variate Analysis (CVA), and multivariate regression to quantitatively identify morphological variation, and the results are more intuitive. The morphological relationships among eight scallop species (Azumapecten farreri, Mizuhopecten yessoensis, Argopecten irradians, Volachlamys hirasei, Swiftopecten swiftii, Gloripallium pallium, Mimachlamys nobilis, Annachlamys striatula) were investigated using geometric morphological methods, the shell edge and ears were digitally labeled using landmarks and semi-landmarks, and the morphological differences of the eight species were obtained by PCA, CVA, and TPS, and further analyzed to establish a phylogenetic tree. The results of PCA and CVA showed that the eight scallop species could be effectively classified from each other in terms of morphological differences by geometric morphometric analysis. In addition, the results combined with the analysis of TPS indicated that the shell and ears differed regularly among these scallop species. The results of phenotypic clustering by their morphological differentiation showed that: A. striatula, M. yessoensis, A. irradians were similar, their shell shapes shared the characteristics of a more elliptical shell and relatively smaller ears; G. pallium and M. nobilis were similar, their shell shapes shared the characteristics of a flatter shell and relatively larger anterior ear; S. swiftii, V. hirasei and A. farreri did not overlap with others. In the clustering process, M. nobilis and G. pallium set intersected, and 10 specimens were mingled, while all other specimens were successfully clustered, with a correct rate of 95.5%. This paper studied eight scallop species using geometric morphology, provided information for the study of morphological taxonomy of Bivalves using geometric morphology.