Ancient spiders on Moa’s Ark? - Biogeography, taxonomy and systematics of the enigmatic odd-clawed spiders

澳大拉西亚是世界上最有趣的生物地理区之一，但地质和气候事件对目前动物的演化史和多样性的影响仍然不是很清楚。新西兰在渐新世海侵期间可能被淹没，也可能没有被淹没，导致当地严重(可能是全部)灭绝，而澳大利亚在过去2000万年里经历了迅速的干旱，从曾经覆盖着茂盛热带雨林的大陆变成了今天占主导地位的干旱沙漠。在这里，我们将调查蜘蛛类的一个古老谱系--奇爪蜘蛛(Gradungulidae)，这种蜘蛛只出现在澳大利亚东部和新西兰南部的森林和洞穴般的栖息地。通过全面的分类样本，我们不仅将使用形态和分子方法研究这个神秘家族的分类和系统发育，还将测试这些蜘蛛是否像最近一项挑战蜘蛛生命树的转录研究所暗示的那样是渐新世后到达新西兰的蜘蛛(“再见冈瓦那”假说)。此外，我们将测试澳大利亚古代遗迹谱系的中生代生物群进化模型，并探索最近提出的关于这块快速干燥大陆上依赖水分的遗迹谱系的生物地理结构和进化能力的假说。我们将使用有针对性的现场收集、传统遗传(Sanger)和新基因组(UCE)方法、生物地理分析、建模方法和分类学相结合的方法来揭开这种真正神秘的澳大拉西亚特有蜘蛛谱系的进化历史。

Australasia is one of the most interesting biogeographical regions in the world but the impact of geological and climatic events on the evolutionary history and diversification of the present fauna are still not well understood. New Zealand may or may not have been submerged during the Oligocene marine transgression causing major (and potentially total) local extinction whereas Australia has undergone rapid aridification in the last 20 million years from a continent once covered with lush rainforests to the arid deserts that dominate today. Here, we will investigate an ancient lineage of arachnids, the odd-clawed spiders (Gradungulidae), which are only occurring in forests and cave-like habitats of eastern Australia and Southern New Zealand. Using a comprehensive taxon sampling we will not only address the taxonomy and phylogeny of this enigmatic family using morphological and molecular methods, but will also test whether these spiders are post-Oligocene arrivers in New Zealand (“Goodbye Gondwana” hypothesis) as implied by a recent transcriptomic study challenging the spider tree of life. Furthermore, we will test a model of mesic biome evolution in Australia for ancient relict lineages and explore recently-proposed hypotheses about the biogeographical structure and evolutionary capacity of a moisture-dependent relict lineage on this rapidly drying continent. We will use a combined approach of targeted field collection, traditional genetic (Sanger) and novel genomic (UCE) methods, biogeographical analyses, modelling approaches and taxonomy to unravel the evolutionary history of this truly enigmatic spider lineage endemic to Australasia.