From the mountains to the coast and back again: ancient biogeography in a radiation of short-range endemic harvestmen from California

The harvestmen genus Calicina is represented by 25 short-range endemic species occurring in the western Sierra Nevada, Transverse and Coast Ranges of California. Our principal aim was to reconstruct the temporal and spatial biogeographic history of this arachnid lineage. We inferred a time-calibrated species tree for 21 of 25 described Calicina species using multiple genes and multilocus coalescent-based methods. This species tree was used as a framework for algorithmic biogeographic and divergence time analyses, and a phylogenetic canonical correlation analysis (CCA) was used to examine the relationship between morphological evolution and environmental variables. Species tree and biogeographic analyses indicate that high-elevation Sierran taxa are early-diverging in Calicina, with subsequent biogeographic “criss-crossing” of lineages from the Sierra Nevada to the Coast Ranges, back to the Sierra Nevada, then back to Coast Ranges. In both the Sierra Nevada and Coast Ranges, distantly-re...

盲蛛Calicina属（Calicina）共有25种狭域特有种（short-range endemic），分布于加利福尼亚州内华达山脉西部、横向山脉（Transverse Ranges）与海岸山脉（Coast Ranges）。本研究的核心目标是重建该蛛形纲支系的时空生物地理历史。我们利用多基因序列及基于多位点溯祖的分析方法，对25个已描述物种中的21种构建了时间校准的物种树（time-calibrated species tree）。该物种树被用作算法生物地理学分析与分化时间分析的研究框架，并通过系统发育典型相关分析（phylogenetic canonical correlation analysis, CCA）探究形态演化与环境变量之间的关联。物种树与生物地理学分析结果显示，内华达山脉的高海拔类群为Calicina属中较早分化的类群，后续支系出现了生物地理上的「交叉」迁移：从内华达山脉迁至海岸山脉，再返回内华达山脉，之后又再次迁至海岸山脉。在内华达山脉与海岸山脉中，亲缘关系较远的...