PRF/M: Evolutionary Morphology of Gastropod Larval Development

腹足动物生物学中的三个问题是本研究的重点。首先，将研究许多海洋腹足类动物在浮游幼虫阶段（正弦波幼虫形态）壳孔变化的发育及其功能意义。其次，对一些原始海洋腹足类动物的幼虫壳发生不寻常的机械变形的发育原因进行了研究。第三个主题涉及描述和评估原始纲腹足类动物发育过程中序列事件和时间的多样性，其具体目标是将数据转化为有助于系统发育分析的特征和特征状态；这样的描述符应该与更传统的形态特征串联使用。这项工作将为软体动物进化形态学的持续和未解决的问题提供信息。前两个问题存在于幼虫壳的功能和进化特征及其与成虫壳的关系的解释领域，解决这些问题需要以比较系统的方式收集发育信息。这两个问题都与在活体和化石腹足类动物的壳中观察到的现象有关。解决第三个问题将培养一种一致的特征和特征状态语言，将发育生物学的丰富词汇转化为一种用于系统和系统发育分析的语言。

Three problems in gastropod biology serve as the focus for this research on metamorphosis and morphological diversity. First, development and functional significance of modifications to shell apertures of many marine gastropod species when in the planktic veliger larval stage (the sinusigeral larval form) will be studied. Second, developmental causes of an unusual mechanical deformation occurring in larval shells of some primitive marine gastropod species are to be investigated. A third topic relates to characterizing and evaluating the diversity of sequential events and timing involved in development of trochoidean gastropods, with the specific goal of translating data into characters and character states useful for phylogenetic analysis; such descriptors should be useful in tandem with more traditional morphological characters. %%% This work will inform persistent and unresolved problems of molluscan evolutionary morphology. The first two problems reside in the realm of functional and evolutionary interpretation of features of the larval shell and its relationship to the adult shell, for which solutions require developmental information gathered in a comparative systematic way. Both questions are relevant to phenomena observable in shells of living and fossil gastropods. Addressing the third problem would cultivate a consistent language of characters and character states that translate the rich vocabulary of developmental biology into a language for systematics and phylogenetic analysis.