恙螨数值分类和属间系统发育关系的研究

Numerical taxonomy and phylogenetic analysis of genera of Trombiculidae

目的了解恙螨数值分类和经典形态学分类的异同,进一步探讨不同属种恙螨间的亲缘进化关系。方法选取国内分布种类较多的10属52种恙螨,每种恙螨选取相互独立的48个形态特征,测定数据并将定性指标赋值,进行系统聚类分析,据聚类树状图分析恙螨属间系统发育关系。结果10属恙螨在λ=15处被分为8组:纤恙螨属与叶片恙螨属聚为一类、背展恙螨属与无前恙螨属聚为一类,其余6属恙螨各自归为一类。结论据聚类树状图推测:背展恙螨属、无前恙螨属和甲梯恙螨属系统分化较早;属间亲缘关系:背展恙螨属与无前恙螨属>背展恙螨属与珠恙螨属、无前恙螨属与珠恙螨属。除纤恙螨属与叶片恙螨属、背展恙螨属与无前恙螨属外,数值分类属级聚类结果与经典形态分类相吻合;亚科级分类与经典形态分类一致。

Objective To understand the taxonomic and evolutionary affinities of Trombiculid mites in different genera on the basis of comparing numerical taxonomy with classical taxonomy（morphological taxonomy）. Methods Fifty two common species of chiggers in 10 genera were selected as samples and 48 independent morphological features of each mite species as variables in the numerical taxonomy.Hierachical analysis was used to make a clustering analysis and to make a dendrogram of clustering groups in the numerical taxonomy.Phylogenetic affinities between different species of chiggers were finally figured out in the light of the clustering dendrogram in the hierachical analysis.Results Based on the dendrogram in the hierachical analysis,52 species of chiggers in Trombiculidae are classified into 8 groups when λ=15.Leptotrombidium and Trombiculindus is merged as one group while Walchia and Gahrliepia another group.The rest 6 genera（Neotrombicula,Herpetacarus,Doloisia,Helenicula,Ascoschoengastia,Chatia） form 6 other groups.The result of dendrogram suggests that Schoengastiella,Walchia and Chatia may be the early groups in systemic phylogeny.Conclusion Schoengastiella,Walchia and Chatia may be the early groups in systemic phylogeny.The phylogenetic sequence of different chigger genera is follows： Walchia and Gahrliepia〉Walchia and Doloisia,Gahrliepia and Doloisia.The results of numerical taxonomy in both genus level and subfamily level are similar to those of classical taxonomy with the exception of Leptotrombidium and Trombiculindus,together with Walchia and Gahrliepia.