摘要
本文以分支系统学为理论依据,分析了剑齿象演化中的近裔性状及其演化极向。以简约性原则建立了反映剑齿象属(Stegodon)各种间系统发育关系的分支图解。与传统的系统学不同,分支图解中不仅表明了某些种之间的租裔序列,而且主要反映了相应的“姐妹群”。同时,进一步运用国外较新的方法,对所建立的分支图解作了检验,并结合地质时代的分布将分支图解转化为系统树。
On the basis of the theory of cladistics, analysis s made of the apomorphy and polarity in the evolution of stegodon. In accordance with parsimony principle, a cladogram is established showing, unlike with the conventional phylogeny, the phylogenetic relationship between various species of stegodon, not only the ancestral-descendent sequence but also 'sister groups'. The cladogram is examined by using a new foreign method and transformed through being mapped noto corresponding geological ages into a phylogeny tree
关键词
长鼻目
剑齿象
发育
proboscidae
classification
trees of evolution/cladogram
