海南岛及周边大陆节板蛛科琼蛛属蜘蛛的系统学和生物地理学研究

Hainan Island as one of continental islands locates in the south of China and the northeastern margin of the Indo-Burma biodiversity hotspot. Prior studies have shown that the climatic changes and sea-level oscillations during the Pleistocene may have influenced the origin, dispersal and distribution patterns of organisms in Hainan Island. Thus, it has increasingly attracted particular attention due to its complicated relationships with Southeast and East Asian continent. Many arachnids with ancient origins, limited dispersal abilities, and restricted habitats have been shown to be excellent models for testing historical biogeographical hypotheses. Yet no such research has been carried out in Hainan Island. The primitively segmented spider genus Qiongthela is distributed in Hainan Island and the southern Vietnam. As an ancient and severely dispersal-limited spider lineage, the diversity and distribution of Qiongthela make them an excellent model for testing historical biogeographical hypotheses. There are, however, four main outstanding problems: (1) the species-level taxonomy of Qiongthela integrating characters with molecular data remains unstudied; (2) the complete phylogenetic relationship of Qiongthela for now is lacking and the phylogenetic position of Qiongthela within the family Liphistiidae has not been solved; (3) the origin, dispersal route and distribution patterns of Qiongthela are still unclear; and (4) the potential geographical barriers caused Qiongthela speciation are unknown, and how climatic changes and sea-level oscillations may have shaped the present-day distribution patterns of Qiongthela has not been explored. In order to address these problems, we will first collect Qiongthela spiders on the whole island and southern Vietnam, and then use four mitochondrial genes, four nuclear genes of all specimens and the genome sequences of selected specimens to reconstruct Qiongthela phylogeny. Moreover, we will take an integrative taxonomy approach to species-level revision of Qiongthela. Furthermore, we will perform divergence dating analyses to estimate the divergence times of Qionghtela species, and to test the geological events as well as potential geographical barriers for speciation.

海南岛位于中缅生物多样性热点地区东北部，岛上物种丰富，与周边大陆物种的亲缘关系复杂，且大部分具有特异性分布特点。研究显示更新世时期海平面的升降对其物种分布模式、起源及扩散有明显影响。因此，海南岛为研究生物地理学提供了一个很好的模式系统，已引起学者们的关注。然而目前国内外还没有以蜘蛛为模式动物对海南岛生物地理进行研究的报道。本课题拟选取穴居于地表、迁移能力差、特异性分布的中纺亚目，节板蛛科，琼蛛属蜘蛛为模式动物对海南岛及周边大陆生物地理进行研究。本项目主要分四部分：（1）形态和分子相结合的琼蛛属种水平上的系统修订；（2）琼蛛属系统演化树的构建；（3）琼蛛属的起源、迁移路线及分布特点的研究；（4）琼蛛属物种形成的潜在地理障碍及海南岛与周边大陆的地质变迁历史的探讨。其研究结果不仅能使我们更深入地了解琼蛛属，完善节板蛛科系统演化关系，而且也将为研究海南岛及周边大陆的生物地理学提供科学依据。

海南岛位于中缅生物多样性热点地区东北部，岛上物种丰富，与周边大陆物种的亲缘关系复杂，且大部分具有特异性分布特点。研究显示更新世时期海平面的升降对其物种分布模式、起源及扩散有明显影响。因此，海南岛为研究生物地理学提供了一个很好的模式系统，已引起学者们的关注。因此本课题拟选取穴居于地表、迁移能力差、特异性分布的中纺亚目，节板蛛科琼蛛属（Qiongthela）蜘蛛为模式动物对海南岛及周边大陆生物地理进行研究。本项目主要分四部分：（1）形态和分子相结合的琼蛛属种水平上的系统修订；（2）琼蛛属系统演化树的构建；（3）琼蛛属的起源、迁移路线及分布特点的研究；（4）琼蛛属物种形成的潜在地理障碍及海南岛与周边大陆的地质变迁历史的探讨。研究结果显示：（1）通过分子物种鉴定分析与形态学特征相结合的整合分类学方法，发现海南岛上的琼蛛属蜘蛛物种种类由之前的仅1种增加到24种，结合形态学特征，共发现有19个新种，另外四个潜在新种需补充成熟样本后才能加以确定，进而完成琼蛛属种水平上的系统修订；（2）利用高通量测序的基因组水平的数据完成了琼蛛属系统演化树的构建，该结果完善节板蛛科系统演化关系；（3）结合系统演化树和分歧时间分析，发现与之前研究不同，琼蛛属与分布于日本地区的Heptathela和Ryuthela成姐妹群，进而改变了之前研究对该属的起源和迁移路线的假设；（4）海南岛的山脉和河流等地理障碍促进了琼蛛属的物种形成，增加其物种多样性。该研究结果不仅能使我们更深入地了解琼蛛属，完善节板蛛科的系统演化关系，而且也为研究海南岛及周边大陆其他生物的系统演化和生物地理学提供数据支持和科学依据。