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

被称为Opiliones或harvestmen的蜘蛛群尚未得到充分研究，特别是Laniatores亚目，其主要谱系之间的进化关系尚不确定。迄今为止，关于拉尼托利亚主要谱系之间关系的研究在正确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，并结合针对分布在世界各地的主要收获群体的实地调查，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，并推断这一群体在南半球的生物地理历史，测试特定的生物地理情景。通过使用新开发的方法，本研究将使UCE方法成为其他收割机和蛛形纲研究人员的有效和有用的方法，这可能对收割机系统学产生潜在的变革性影响，并提高收割机在更广泛的系统学领域的知名度。分子系统学领域正在从使用单一或多基因数据集的传统研究过渡到使用100 - 1000个基因的系统基因组研究。数据量的增加有助于解决关系和分类问题，特别是在像蛛形纲这样的研究不足的群体中。本研究将尝试通过使用超保守元件的系统基因组方法来解决未解决的系统和分类问题。将这些位置不确定的关键类群纳入研究，结合系统基因组学，将得到一个稳定的分类体系。此外，这些收割机的一般生物学特性（低扩散能力和有限分布）使它们成为基于假设的生物地理分析的理想候选者。不间断的全球分布和最近估计的分化时间表明，这些谱系很古老，可能早于盘古大陆的分裂。

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.