DISSERTATION RESEARCH: Phylogenomics and Biogeography of Early-diverging Laniatores (Opiliones) using Ultraconserved Elements

被称为Opiliones或收割者的蜘蛛群，特别是主要谱系之间的进化关系不确定的Laniatores亚目，研究不足。到目前为止，对Laniatores主要谱系之间关系的研究在正确的分类方面产生了相互矛盾的结果。目前的研究项目将使用新开发的DNA测序技术，结合针对分布在世界各地的主要收割者群体的实地调查，包括美国和新西兰研究人员之间的合作。本研究的目标是重建这些谱系之间的进化关系，产生一个稳定的分类，并推断这组在南半球的地理历史，测试特定的地理场景。通过使用新开发的方法，本研究将建立UCE方法作为其他收割者和蛛形纲动物研究人员的有效和有用的方法，这可能对收割者系统学产生潜在的变革性影响，分子系统学领域正在从传统的使用单一或多个基因的研究向分子系统学领域转变，基因数据集，用于对具有100 - 1000个基因的基因组研究进行分析。数据量的增加有助于解决关系和解决分类问题，特别是在研究不足的类群如蛛形纲动物中。这项研究将试图解决未解决的系统和分类学问题，通过一个超保守的元素的基因组方法。这些关键类群的位置是不确定的，加上基因组学的列入将导致一个稳定的分类。此外，这些收割者的一般生物学特征（低扩散能力和限制性分布）使他们成为基于假设的地理分析的理想候选人。间断的全球分布和最近估计的分歧时间表明，这些谱系是古老的，可能早于泛大陆的分裂。

The spider group known as Opiliones, or harvestmen, is understudied, particularly the suborder Laniatores where the evolutionary relationships among major lineages are uncertain. To date, research on the relationships among major lineages of Laniatores has produced conflicting results in regards to the proper classification. The current research project will use newly developed DNA sequencing technologies combined with fieldwork targeting key harvestmen groups distributed across the world, including a collaboration between researchers in the U.S. and New Zealand. The goals of this research are to reconstruct the evolutionary relationships among these lineages, producing a stable taxonomy, and to infer the biogeographic history of this group in the southern hemisphere, testing specific biogeographic scenarios. By using newly developed methods, this research will establish the UCE approach as a valid and useful method for other harvestmen and arachnid researchers, which may have a potentially transformative effect on harvestmen systematics, and increase the visibility of harvestmen in the broader field of systematics.The field of molecular systematics is transitioning from traditional studies using single- or multi-gene datasets to phylogenomic studies with 100s - 1000s of genes. This increase in the amount of data helps resolve relationships and settle taxonomic issues, particularly in understudied groups like arachnids. This research will attempt to address unresolved systematic and taxonomic issues through a phylogenomic approach using ultraconserved elements. The inclusion of these key taxa whose placement is uncertain coupled with phylogenomics will lead to a stable taxonomy. Additionally, the general biological characteristics of these harvestmen (low dispersal ability and restricted distributions) make them ideal candidates for hypothesis-based biogeographic analyses. The disjunct worldwide distribution and recently estimated divergence times suggest that these lineages are ancient, likely predating the breakup of Pangea.