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

9701745只卡尔森蜗牛被放在纳萨里亚科，代表了当今蜗牛多样性的重要部分。已知的活物种有数百种；此外，在至少6000万年前的化石记录中还出现了数百种物种。尽管有大量的物种和大量的化石记录，但纳萨里亚目腹足类的遗传学(系统发育史)还没有被很好地了解。解决这一系统发育历史的一种方法包括在单一分析中使用来自活物种和化石物种的数据。然而，来自化石的数据比来自活的蜗牛的数据更不完整，这种相对不完整的情况造成了问题。因此，化石数据以前没有被包括在基于现存物种的系统发育历史重建中。在这项研究中，Sandra Carlson和博士生David Haasl将结合贝壳和解剖特征分析以及对Nassariine物种化石历史的比较分析，重建Nassariinae亚科的系统发育历史或家谱。将从博物馆的收藏品中获得每个主要Nassariine类群的代表，并对其进行信息丰富的贝壳特征检查。代表性物种的解剖特征将从文献和标本解剖中获得。每一主要类群中最古老的化石将被记录下来。将通过比较在包含和不包含时间化石数据的情况下构建的树来测试将化石数据与基于特征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.