Richter Stefan
Allgemeine & Spezielle Zoologie, Institut für Biowissenschaften, Universität Rostock, Universitätsplatz 2, Rostock, 18055, Germany.
Cladistics. 2017 Oct;33(5):540-544. doi: 10.1111/cla.12180. Epub 2016 Nov 2.
In a recent debate, either synapomorphy and symplesiomorphy or only synapomorphy have been claimed to be synonymous or equivalent to homology. In my view, exactly the same relationship exists between homology supported by a congruence test on the one hand and synapomorphy as well as symplesiomorphy on the other hand. Both conditions become established at the same time with the process of rooting of an unrooted topology. I, however, do not consider the concept of homology equal or synonymous to that of synapomorphy and symplesiomorphy. In my view, they represent different perspectives on the same phenomenon, i.e. correspondence by common origin. Homology has no implication on the direction of transformation, whereas symplesiomorphy as "primitive" condition and synapomorphy as "derived" condition refer directly to phylogenesis, the real historical evolutionary process of speciation and transformation. In addition, synapomorphy and symplesiomorphy might also refer to a character state that refers to the absence of a structure/organ, which creates problems with traditional homology concepts. Hennig's terms synapomorphy and symplesiomorphy are necessary and sufficient for the evolutionary interpretation of character states. For what is corroborated in an unrooted topology as the result of a congruence test, I suggest as a new term "synmorphy" because it can well be applied also to those characters where one state represents the absence of a structure/organ. The place for homology in morphological cladistics, however, is restricted to the characterization of the relationship between different character states of one transformation series (i.e. character).
在最近的一场辩论中，有人声称共衍征和共祖征或者只有共衍征与同源性是同义的或等同的。在我看来，一方面通过一致性检验支持的同源性与另一方面的共衍征以及共祖征之间存在着完全相同的关系。这两种情况在无根拓扑结构的生根过程中同时确立。然而，我并不认为同源性的概念与共衍征和共祖征的概念相等或同义。在我看来，它们代表了对同一现象的不同视角，即共同起源的对应关系。同源性对转变方向没有影响，而共祖征作为“原始”状态和共衍征作为“衍生”状态则直接涉及系统发生，即物种形成和转变的真实历史进化过程。此外，共衍征和共祖征也可能指的是一种特征状态，即指某种结构/器官的缺失，这给传统的同源性概念带来了问题。亨尼希的术语共衍征和共祖征对于特征状态的进化解释是必要且充分的。对于在无根拓扑结构中作为一致性检验结果得到证实的情况，我建议使用一个新术语“共态形”，因为它也可以很好地应用于那些其中一种状态表示某种结构/器官缺失的特征。然而，同源性在形态分支系统学中的位置仅限于对一个转变系列（即特征）的不同特征状态之间关系的描述。
