The interrelationships and lines of descent of living insects.
The interrelationships and lines of descent of living insects.
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DOI：
10.1155/1938/18939
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发表时间：
1938-01-01
期刊：
影响因子：
--
通讯作者：
Crampton, G. C.
中科院分区：
文献类型：
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作者：
Crampton, G. C.
在随附的遗传树中显示的血统线应该被解释为好像这个数字是一个三维的（如树枝的基部附着所示），因为通常的方法是在一个平面上画出一棵二叉树来描绘血统，并不能揭示出几条血统可能会聚在一个共同祖先上的事实，也没有准确地指出这些血统之间复杂的相互关系。事实上，由会聚线组成的圆锥截面将更好地说明一些下降线”水平”和”垂直”过渡的事实，但是说明附图中所示下降线的相互关系的方法对于所有实际目的都足够好，如果这个图被解释为一个三维的图的话。在系统发生树的底部显示的假设的”原软甲纲”，代表已灭绝的高等甲壳类（如Tanaidacea、Myosteacea、Anaspidacea等）的共同祖先。昆虫和“多足动物”。头部特征、无柄眼睛、单髁下颌骨、分化的门齿和突出的臼齿区域、大的副颌、细长的多节尾足类以及Tanaidacea的其他特征（如Tanais、Approxides、Leptochelia等）。这一点令人震惊地暗示了机械虫中类似结构的前体，而Tanaidacea的祖先（在图中以假设的”Proto-tanaidacea“为代表）必须与更多的dir有着极其密切的关系。六足动物的祖先（在图中以假设的”原六足动物“表示）
The lines of descent shown in the accompanying phylo-genetic tree should be interpreted as though the figure were a three dimensional one (as is indicated by the basal attachments of the branches ofthe tree), since the usual method of portraying the lines of descent in the form of a dichotomously branching tree, drawn in one plane, does not bring out thefact that several lines of descent may converge upon a common ancestry, and does not indicate the complicated interrelationships of these lines of descent at all accurately. In fact, sections of cones made up ofconverging lines would better illustrate the fact that some lines of descent intergrade" horizontally" as well as" vertically," but themethod of illustrating the interrelationships of the lines of descent shown in the accompanying figure will serve well enough for all practical purposes, if the figure is interpreted as a three dimensional one.The hypothetical" Protomalacostraca" shown at thebase of the phylogenetic tree, representthe extinct common an-cestors of the higher Crustacea (such as the Tanaidacea, Mysidacea, Anaspidacea, etc.) insects and" myriopods". The character of the head, with its sessile eyes, the monocondylar mandibles, with their differentiated incisor and projecting molar regions, the large paragnaths, the slender multiarticulate, cerci-like uropods, and other feature of the Tanaidacea (such as Tanais, Apseudes, Leptochelia, etc.) are strikingly suggestive of the precursors of similar structures in the Machiloid insects, and the ancestors of the Tanaidacea (represented by the hypothetical" Proto-tanaidacea in the diagram) must have been extremely closely related to the more dir. ect ancestors of the Hexapoda (rep-resented in the diagram by the hypothetical" Protohexa-