Evolutionary History of Crinoid Stalks: Architecture, Connective Tissues, Biomechanics and Taphonomy

最近完成的对活的海百合的茎的形态、精细结构、攻丝和功能形态的研究为重新审视古生代海百合的形态和功能提供了必要的信息。柄形态的模式将通过描述古生代类群柄中结缔组织(韧带)的分布来记录。这将通过检查柱状物的微观结构(立体)，并通过解释碎裂茎的丝状模式来实现。然后，形态数据将被用于对鸡冠状茎的功能分析，将茎建模为悬臂梁。我们已经开发和测试的一个大光束偏转的修正模型将允许我们检查不同的茎结构如何响应不同的能量区域。这些结果不仅将作为一种古生态学工具，例如重新解释海百合在不同环境中的分布模式，而且还将为检验更高的海百合分类群之间的关系假说提供新的特征(结缔组织的类型和定位模式)。

Recently completed studies on the morphology, fine-structure, taphonomy, and functional morphology of stalks of living crinoids provide the necessary information to reexamine the morphology and function of stalks of Paleozoic crinoids. Patterns of stalk morphology will be documented by describing the distribution of connective tissue (ligaments) in the stalks of Paleozoic taxa. This will be done by examining the microstructure (stereom) of columnals, and by interpreting taphonomic patterns of fragmented stalks. The morphological data will then be used in a functional analysis of crinoid stalks, with the stalk modeled as a cantilever beam. A modified model for large beam deflections which we have developed and tested will allow us to examine how different stalk architectures responded to different energy regimes. These results will serve not only as a paleoecological tool, to reinterpret, for example, the distributional patterns of crinoids among different environments, but should also provide new characters (types and patterns of positioning of connective tissue) for testing hypotheses of relationship among higher crinoid taxa.