基于形态学差异探讨秦岭细鳞鲑亚种有效性问题

THE VALIDITY OF SUBSPECIES OF BRACHYMYSTAX LENOK TSINLINGENSIS LI BASED ON MORPHOLOGICAL DIFFERENCE ANALYSIS

  • 摘要: 秦岭细鳞鲑(Brachymystax lenok tsinlingensis Li)的亚种分类地位自命名以来一直饱受争议。研究运用单因素方差分析、主成分分析、判别分析、聚类分析及差异系数检验法, 对秦岭细鳞鲑和黑龙江流域的尖吻细鳞鲑(B. lenok lenok)和钝吻细鳞鲑(B. tumensis)的5项可数性状和34项标准化后的比例性状进行统计分析。单因素方差分析结果表明, 尖吻细鳞鲑、钝吻细鳞鲑和秦岭细鳞鲑在32项比例性状和5项可数性状上存在极显著差异(P<0.01); 主成分分析结果显示, 贡献率较大的前3个主成分的累计贡献率为92.779%; 以逐步判别分析方法选用14个判别效果较好的比例性状构建了3个细鳞鲑类群的判别函数, 综合判别率为99.4%。基于欧式距离矩阵法构建的形态学聚类图显示, 秦岭细鳞鲑和尖吻细鳞鲑距离较近, 而与钝吻细鳞鲑距离较远。据Mayr 75%亚种识别和划分规则, 34项比例性状和5项可数性状中, 尖吻细鳞鲑和秦岭细鳞鲑第一鳃弓外鳃耙数目的差异系数大于1.28, 而钝吻细鳞鲑和秦岭细鳞鲑有31项比例性状和2项可数性状的差异系数高于1.28。据分析结果, 结合秦岭细鳞鲑地理隔离的事实及其与尖吻细鳞鲑和钝吻细鳞鲑的形态差异, 推断秦岭细鳞鲑与黑龙江流域内的尖吻细鳞鲑的形态差异程度至少已达亚种水平。

     

    Abstract: The taxonomic status of Brachymystax lenok tsinlingensis Li, distributing in Qinling area of China, is controversial since it was found. In this study, the morphological differences among three Brachymystax groups (B. lenok lenok (Pallas, 1773) and B. tumensis (Mori, 1930) from Amur river basin and B. lenok tsinlingensis (Li, 1966) from the Qinling area) were investigated, including five meristic characters and thirty-four standardized morphometric characters through multivariate morphometrics methods. Results of one-way ANOVA showed that five meristic characters and thirty-two standardized morphometric characters were significantly different (P<0.01) among three groups. Principal component analysis indicated that the cumulative contribution of the top three principal components was 92.779%. Effective linear discriminant formulas were obtained from fourteen standardized morphometric characters, with the discriminating accuracy of 99.4% in the three groups. The tree diagram of these groups based on the squared Euclidean distance showed thatB. lenok tsinlingensis had a close distance with B. lenok lenok, but it is distant from B. tumensis. The coefficient of difference (CD) for the outer gill raker number in the first gill arch between B. lenok tsinlingensis and B. lenok lenok is larger than the threshold value of 1.28, and the CD for the thirty-one standardized morphometric characters and two meristic characters in B. lenok tsinlingensis and B. tumensis was also greater than 1.28. According to the results listing above, and the geographical isolation of B. lenok tsinlingensis together with its morphological differences from B. lenok lenok and B. tumensis, it is deduced that the morphological difference between B. lenok tsinlingensis in Qinling and B. lenok lenok in Amur river basin has at least reached subspecies level.

     

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