摘要
本文对中国15种叶形吸虫成虫的12项成虫形态特征进行了聚类分析和主成分分析,结果表明:运用8种不同的聚类方法所得到的谱系分枝图基本一致,即15种叶形吸虫明显地可分为两大亚群,它们分别与Phyllodistomum和Catoptroides亚属相对应。主成分分析所得到的坐标定位图则进一步证实了这一结果,并且显示了在叶形属吸虫中,成虫体形因素、卵黄腺类型及生殖腺相互位置等特征是该属吸虫的主要分类依据。
The fifteen species of phyllodistomes from fishes in China are studied with the hierarchical cluster analysis and principal components analysis (PCA), based on twelve structural characters of adults commonly used in traditional classification of genus Phyllodistomum.The clustering analysis of Euclidean taxonomic distance using different methods have got eight dendrograms. In general these phenograms show similar results, that is, the fifteen species of phyllodistomes are basically clustered into two sub-groups. Sub-group Ⅰ consists of three sections: There are two species (P. sinipercae Long et Wai, 1958 and P. sinense Wu, 1937) in section-1, three species (P. anguilae Long et Wai, 1958, P. lesteri Wu, 1938 and P. mingensis Tang, 1985) in section-2, and two species (P. hemiculteri Wang, 1984, and P. plagiognathops Wang, 1984) in section-3. Sub-group Ⅱ also consists of three sections: There are three species (P. carassii Long et Wai, 1958, P. bai Long et Wai, 1958 and P. pawlovskii Zmeev, 1936) in section-4, two species (P. parasiluri Yamaguti, 1934 and P. clariasi Lai et al., 1985) in section-5, and two species (P. sanyangense Wang, 1982 and P. serrispatula Chin, 1963) in section-6. The fourteen species of phyllodistomes are digeneans from freshwater fish-es, and P. pearsei Holl, 1929 is the one from marine fish. It seems that the marine species is a relatively independent branch in the hierarchical dendrograms, however it is more related to P. siniperae, which is clustered in sub-group Ⅰ. The sub-group Ⅰ (seven freshwater species and one marine species) and the sub-group Ⅱ(another seven freshwater species) correspond with two subgenera, Phyllodistomum Pigulevsky, 1952 and Catoptroides Odhner, 1902 respectively.The ordination of the structural characters of adult phyllodistomes obtained by PCA fur- ther demonstrates the same result mentioned above. The seven freshwater species clustered in sub-group Ⅰ are located mostly within the second quadrant in the ordination of the two di-mentions (Ⅰ and Ⅱ principal component). Another seven freshwater species clustered in sub-group Ⅱ are located within the fourth quadrant and a marine species at a corner of the first. Therefore, we believe that it is save and reliable to divide the fifteen Chinese phyllodistomes into the two subgenera.Our PCA indicates that the shape of adult body (body llenght-width ratio and acetabulum relative position), the type of vitellarium (intact and/or branched) and the mutual position of the gonads are the most important characters in taxonomy of the genus Phyllodistomum. The relative position of posterior testis is plssibly a potential diagnostic character available for use in the classification of the phyllodistomes.The assessment of the eight cluster methods used in the present study with cophenetic correlation coefficient shows that unweighted pair-group method arithmatic averages (UPGMA) is one of the best clustering methods (Rcs value is 0.87115) and the distance coefficient can bear more disturbance for the numerical taxonomy of the genus Phyllodistomum.The data provided by Prof. Tang Zhongzhang (1985) and us suggest that three closely related species (P. anguilae, P. lesteri and P. mingenstise) compose a primitive group in genus Phyllodistomum. The problems of systematics in the genus is discussed.
出处
《动物学报》
SCIE
CAS
CSCD
1992年第1期17-22,共6页
ACTA ZOOLOGICA SINICA
关键词
叶形属吸虫
数值分类
聚类分析
Phyllodistomum, Numerical taxonomy, Cluster analysis, Principal components analysis (PCA)
