Morphological Diversity of Paleozoic Pelmatozoan Echinoderms

一些有趣的假说被提出，特别是那些起源于早古生代的分支，在历史上关于形态多样性的大规模时间模式。然而，关于多样性的进化假说的测试要么使用分类多样性作为形态多样性的替代，要么集中在相对较小规模的模式上。这项拟议的研究将调查古生代棘皮纲大型分支以及较小分支的形态多样性的时间模式。具体地说，将确定形态多样性是否集中在一个支系的早期历史中，以及形态多样性和分类多样性之间是否存在时间上的定向差异。形态多样性将直接测量，使用基于离散字符数据的不同测量。这些数据将从已公布的物种描述和博物馆标本中收集。对形态进行量化的方法将允许在比迄今所采用的更广泛的分类尺度上直接记录形态多样性模式，因此将提供与进化生物学中感兴趣的主要问题相关的重要的新数据。

Several intriguing hypotheses have been proposed regarding large-scale temporal patterns of morphological diversity in the history of clades, particularly those originating in the early Paleozoic. However, the testing of evolutionary hypotheses regarding diversity has either used taxonomic diversity as a proxy for morphological diversity, or focused on patterns at relatively small scales. The proposed research will investigate temporal patterns of morphological diversity in large clades of Paleozoic echinoderms, Class Crinoidea, as well as in smaller clades. Specifically, it will be determined whether morphological diversity is concentrated early in the history of a clade, and whether there are temporally directed differences between morphological and taxonomic diversity. Morphological diversity will be measured directly, using dissimilarity measures based on discrete-character data. These data will be collected from published species descriptions as well as museum specimens. The approach adopted for quantifying morphology will allow direct documentation of morphological diversity patterns at a broader taxonomic scale than has heretofore been practiced, and will therefore provide important new data relevant to major questions of interest in evolutionary biology.