Dissertation Research: The Effect of Stratocladistics on the Phylogenetic Analysis of Nassariine Gastropods

9701745 CARLSON 属于 Nassariinae 亚科的蜗牛代表了当今蜗牛多样性的重要组成部分。 已知有数百种现存物种；此外，化石记录中还出现了数百种至少有 6000 万年历史的物种。 尽管纳萨里腹足动物的物种数量众多且有重要的化石记录，但其谱系学（系统发育史）尚不清楚。 解决这一系统发育历史的一种方法包括在一次分析中使用来自现存物种和化石物种的数据。 然而，来自化石的数据比来自活体蜗牛的数据更不完整，这种相对不完整导致了问题。 因此，化石数据以前没有被包含在基于现存物种的系统发育历史重建中。 在这项研究中，桑德拉·卡尔森（Sandra Carlson）和博士生大卫·哈斯尔（David Haasl）将结合对贝壳和解剖特征的分析以及对纳萨里亚科物种化石历史的比较分析，重建纳萨里纳亚科的系统发育历史或家谱。 将从博物馆收藏中获取每个主要纳萨里恩群体的代表，并检查其信息丰富的贝壳特征。 代表性物种的解剖特征将从文献和标本解剖中获得。 每个主要类群最古老的化石都会被记录下来。 将通过比较包含和不包含时间化石数据构建的树来测试将化石数据与基于性状的分析相结合的有用性。

9701745 CARLSON Snails placed in the subfamily Nassariinae represent a significant portion of present-day snail diversity. Hundreds of living species are known; in addition, hundreds of species appear in a fossil record of at least 60 million years in age. The geneaology (phylogenetic history) of nassariine gastropods is not well understood, despite the large number of species and significant fossil record. One approach to resolving this phylogenetic history includes using data from both living and fossil species in a single analysis. However, the data from fossils are more incomplete than the data from living snails, and this relative incompleteness has caused problems. Consequently, fossil data have previously not been included in phylogenetic history reconstructions based on extant species. In this research, Sandra Carlson and doctoral candidate David Haasl will reconstruct the phylogenetic history or family tree of the subfamily Nassariinae, combining both an analysis of shell and anatomical traits and a comparative analysis of the fossil history of nassariine species. Representatives of each major nassariine group will be obtained from museum collections and examined for informative shell traits. Anatomical traits of representative species will be obtained from the literature and from dissections of specimens. The oldest fossil occurrence of each major group will be noted. The usefulness of combining fossil data with a trait-based analysis will be tested by comparing trees constructed both with and without the inclusion of temporal fossil data.