不同鳊鲂属鱼类群体的形态差异分析

Morphological variations of genera Parabramis and Megalobrama teleost populations

运用3种多元统计方法对我国鳊属长春鳊(Parabramis.pekinensis)、鲂属团头鲂(Megalobrama.amblycephala)、东江三角鲂(Megalobrama.terminalis)、钱塘江三角鲂(Megalobrama.terminalis)、厚颌鲂(Megalobrama.pellegrini)和广东鲂(Megalobrama.hoffmanni)6个群体的可数性状、可量性状和框架性状的形态学差异进行了分析。结果显示,鳊鲂属鱼类6群体在侧线鳞数、侧线上鳞数、侧线下鳞数、背鳍条数、胸鳍条数、腹鳍条数、臀鳍条数等7项形态可数性状上的差异不显著(P>0.05)。对9项可量比例参数和20项框架比例参数的聚类分析结果表明,团头鲂与同属的厚颌鲂、三角鲂亲缘关系较近,这3个鲂属种群与鳊属长春鳊形态差异较大,与同为鲂属的广东鲂形态差别最大;另外,聚类分析表明三角鲂的2个地理群体(东江三角鲂、钱塘江三角鲂)也存在一定的形态差异。判别分析构建了鳊鲂属鱼类6群体的判别函数,其综合判别率为93.7%。主成分分析提取的前2个主成分的累积贡献率为77.9%,其中主成分1的贡献率为70.9%,对鳊鲂属鱼类群体间形态学差异起决定性作用的特征集中在背腹轴方向。

In the present study,three multivariate morphometrics analyses were introduced to assess the morphological variations on meristic parameters,measurable scaling parameters and truss network scaling parameters in Parabramis pekinensis,Megalobrama amblycephala,M. terminalis（ Dongjiang population and Qiantangjiang population）,M. pellegrini and M. hoffmanni in China. Results were shown below： No significant variation（ P 0. 05） was observed on seven meristic parameters such as scale number on lateral line,scale number above lateral line,scale number beneath lateral line,soft dorsal fin（ spines,rays）, pectoral fin（ spines,rays）,pelvic fin（ spines,rays）,anal fin（ spines,rays） among Parabramis and Megalobrama species. Based on nine measurable scaling parameters and twenty truss network scaling parameters,cluster analysis presented a relatively close relationship between M. amblycephala,M. terminalis and M. pellegrini, and these three species had relatively far relationship with the species of genus Parabramis,while they all had great morphological variation with the species M. hoffmanni. Meanwhile, certain morphological variations were detected between Dongjiang population and Qiantangjiang population of the species M. terminalis. Discriminant analysis outputted six discriminant functions with a comprehensive accuracy rate of 93. 7% among the six populations of genera Parabramis and Megalobrama. The cumulative contributive proportion of two chief principal components extracted by principal component analysis was 77. 9%,in which principal component 1 accounted for 70. 9%. Characters that played key roles in inter-species morphological variation among Parabramis and Megalobrama concentrated mainly in the direction of dorsalventral axis.