Data from: 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-related parapatric lineages essentially never occur in sympatry. CCA reveals that in both the Coast Ranges and the Sierra Nevada, distant phylogenetic relatives evolve convergent morphologies. Our evidence shows that Calicina is clearly dispersal-limited, with an ancient biogeographic history that provides unique insight into the complex geologic evolution of California since the mid-Paleogene.

盲蛛属Calicina共有25个狭域特有种，分布于加利福尼亚州内华达山脉西部、横贯山脉与海岸山脉。本研究的核心目标为解析该蛛形动物支系的时空生物地理历史。我们基于多基因数据与多位点溯祖分析方法，对25个已描述物种中的21个构建了时间校准的物种树。以此物种树为框架，开展基于算法的生物地理与分化时间分析，并采用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间的关联。物种树与生物地理分析结果显示，内华达山脉的高海拔类群为Calicina属内早期分化的类群，后续支系发生了生物地理层面的“交错穿梭”：从内华达山脉扩散至海岸山脉，再折返内华达山脉，随后又重回海岸山脉。无论在内华达山脉还是海岸山脉，亲缘关系较远的邻域支系几乎从未出现同域分布现象。CCA分析结果表明，在海岸山脉与内华达山脉中，亲缘关系较远的系统发育类群演化出了趋同的形态特征。本研究证据显示，Calicina属类群明显具有扩散受限的特性，其古老的生物地理历史为解析古近纪中期以来加利福尼亚州复杂的地质演化过程提供了独特视角。