Data from: Imprints of multiple glacial refugia in the Pyrenees revealed by phylogeography and palaeodistribution modelling of an endemic spider

Mediterranean mountain ranges harbour highly endemic biota in islandlike habitats. Their topographic diversity offered the opportunity for mountain species to persist in refugial areas during episodes of major climatic change. We investigate the role of Quaternary climatic oscillations in shaping the demographic history and distribution ranges in the spider Harpactocrates ravastellus, endemic to the Pyrenees. Gene trees and multispecies coalescent analyses on mitochondrial and nuclear DNA sequences unveiled two distinct lineages with a hybrid zone around the northwestern area of the Catalan Pyrenees. The lineages were further supported by morphological differences. Climatic niche-based species distribution models (SDMs) identified two lowland refugia at the western and eastern extremes of the mountain range, which would suggest secondary contact following postglacial expansion of populations from both refugia. Neutrality test and approximate Bayesian computation (ABC) analyses indicated that several local populations underwent severe bottlenecks followed by population expansions, which in combination with the deep population differentiation provided evidence for population survival during glacial periods in microrefugia across the mountain range, in addition to the main Atlantic and Mediterranean (western and eastern) refugia. This study sheds light on the complexities of Quaternary climatic oscillations in building up genetic diversity and local endemicity in the southern Europe mountain ranges.

地中海山脉在类岛屿状生境中孕育了高度特有的生物区系。其地形异质性为山地物种在重大气候变化事件期间于避难所中存续提供了契机。本研究针对比利牛斯山特有蜘蛛Harpactocrates ravastellus，探讨第四纪气候振荡对其种群历史与分布范围的塑造作用。基于线粒体与核DNA序列的基因树及多物种溯祖分析显示，该蜘蛛存在两个显著支系，二者在加泰罗尼亚比利牛斯山西北部区域形成杂交带；该两支系的分化亦得到形态差异数据的佐证。基于气候生态位的物种分布模型（SDMs）识别出该山脉东西两端的两处低地避难所，这表明两处避难所的种群在冰期后扩张后发生了二次接触。中性检验与近似贝叶斯计算（ABC）分析结果显示，多个当地种群在经历严重瓶颈效应后发生了种群扩张；结合显著的种群分化现象，该结果佐证了除主要的大西洋及地中海（东西部）避难所之外，该山脉各处的微避难所亦为种群在冰期的存续提供了支撑。本研究阐明了第四纪气候振荡在塑造南欧山地类群遗传多样性与地方特有性过程中的复杂机制。