Approaches to systematic and evolutionary studies of perplexing groups: an example using fenestrate Bryozoa
Approaches to systematic and evolutionary studies of perplexing groups: an example using fenestrate Bryozoa
复制标题
对令人困惑的群体进行系统和进化研究的方法：使用开窗苔藓虫的例子
DOI：
10.1017/s0022336000030729
复制
发表时间：
1991
影响因子：
1.4
通讯作者：
S. Hageman
中科院分区：
文献类型：
--
作者：
S. Hageman
离散类群的识别是生物科学中一个持久的问题，特别是对于那些在低分类水平上表现出高度同胚性的群体工作的分类学家来说。选择用于进行分类区分的字符类型和数量很重要，因为它反映了整个群体的分类概念。通常，用于开发分类的字符的有效性没有记录，因此最终的分类是值得怀疑的。然而，可以通过数值分析来测试分类的客观性，并且可以通过各种统计技术来评估特征的相对价值，以进行分类划分。此外，对性格状态分布的评估可以深入了解任何群体的进化历史。本研究提供了这样的分析。有孔隐口动物苔藓虫在许多上古生代岩石中丰富且多样，因此对于各种古生物学研究可能非常有用。然而，开窗剂的研究受到必要的复杂制备技术和同胚遇到的问题的阻碍。此外，不充分的方法的不一致的应用也导致了分类法的不令人满意。聚类分析和判别分析的结果表明，可以客观地识别开窗物种。当使用所有可用的字符时，物种区别最为清晰，尽管某些字符比其他字符更具诊断性。聚类和判别分析的结果表明，开窗属代表了与允许进入新的适应区的关键特征的发展相关的主要进化转变。关键特征允许对属进行寡定分类，这不仅仅是为了简化分类分析而创建的人工制品。适应区内物种的多样化导致了属级和物种级特征的自然层次结构。不同适应区内物种水平的迭代进化导致了大量的同胚性。形态计量分析为这个传统问题群体的古生物学的几个方面提供了见解。类似的综合研究可能对其他群体同样有效。
Recognition of discrete taxa is an enduring problem in the biological sciences, especially for taxonomists who work with groups that display a great degree of homeomorphy at low taxonomic levels. Selection of the type and number of characters used to make taxonomic distinctions is important because it reflects taxonomic concepts for a group as a whole. Often the validity of characters used to develop classifications is not documented and resulting classifications are therefore suspect. However, classifications can be tested for their objectivity with numerical analysis and characters can be evaluated for their relative value for making taxonomic splits by a variety of statistical techniques. In addition, evaluation of the distribution of character states can lead to insights into evolutionary histories of any group. This study provides such an analysis. Fenestrate cryptostome Bryozoa are abundant and diverse in many upper Paleozoic rocks, and are therefore potentially highly useful for a variety of paleontologic studies. However, study of fenestrates is hampered by necessary complex preparation techniques and problems encountered with homeomorphy. In addition, inconsistent applications of inadequate methodologies have contributed to an unsatisfactory taxonomy. Results from cluster and discriminant analyses demonstrate that fenestrate species can be objectively recognized. Species distinctions are most clear when all available characters are used, although some characters are more diagnostic than others. Results from cluster and discriminant analyses suggest that fenestrate genera represent major evolutionary shifts associated with the development of key character(s) that allowed entry into new adaptive zones. Key characters allow for an oligothetic classification of genera, which is not merely an artifact created to simplify taxonomic analysis. Diversification of species within adaptive zones resulted in a natural hierarchy of genus-level and species-level characters. Iterative evolution at the species level within separate adaptive zones resulted in a great deal of homeomorphy. Morphometric analysis provides insights into several aspects of the paleobiology of this traditionally problematic group. Similar comprehensive studies may prove equally productive for other groups.