DISSERTATION RESEARCH: How Ecological, Behavioral, and Morphological Traits have Shaped Diversification Patterns in Assassin Spiders

刺客蜘蛛有一个神秘的分布，其中许多灭绝的化石谱系只知道来自北方半球和所有生活的物种被限制在南半球。如果蜘蛛曾经广泛分布，现在只作为幸存者存在于孤立大陆的小栖息地，这种分布可能会出现。 或者，这种分布可能是大陆分裂或古代分散的结果。这项研究旨在确定现存和灭绝物种之间的进化关系，这将有助于加深对地理和进化历史的理解。将使用X射线扫描技术检查化石物种的形态特征，目的是将化石物种放入进化关系的分支图中。目前的研究利用了一个独特的机会来研究具有灭绝和存活物种的蜘蛛谱系，其中包括似乎在非常不同的时间段和跨多个大陆出现的物种辐射。这项研究将允许评估化石谱系的形态特征，并将研究这些特征是否可以用来理解灭绝类群的过去行为。 这些发现可能会与其他灭绝和活着的生物体的模式进行比较，以测试这些模式是否适用于地球历史。这项工作的结果将被用于显示在加州科学院。

Assassin spiders have an enigmatic distribution where numerous extinct fossil lineages are known only from the northern hemisphere and with all living species being restricted to the southern hemisphere. This distribution could have arisen if the spiders were once widespread and now only exist as survivors in small habitat patches on isolated continents. Alternatively, it could be that this distribution is a result of continental breakup or ancient dispersal. This study seeks to determine the evolutionary relationship between living and extinct species, which will enhance understanding of biogeographic and evolutionary history. Morphological characters of fossil species will be examined using X-ray scanning techniques with the purpose of placing fossil species into a phylogeny, a branching diagram of evolutionary relationships. The current study makes use of a unique opportunity to study a lineage of spiders with extinct and living species, which includes species radiations that appear to have arisen at very different periods of time and across multiple continents. The study will allow assessment of morphological characteristics of fossil lineages and will examine whether these characteristics can be used to understand past behaviors in extinct taxa. These discoveries may then be compared to patterns in other extinct and living organisms to test whether the patterns are general for earth history. Results of this work will be used in displays at the California Academy of Sciences.