Population genetics and ecological niche of a California woodland scorpion, Uroctonus mordax, in the face of climate change

The Western forest scorpion (Uroctonus mordax) is found in forested regions along the Cascade, Coast, and Sierra Nevada Ranges in the western United States. Previous work employing SNP data from RADSeq discovered a deep divergence among northern (Washington, Oregon, parts of northern California) and southern (California) clades and distinct population structuring within these two clades. In this project, we assemble a high-coverage reference genome assembled from PacBio HiFi and Omni-C reads, for a genome size of about 4 Gb. For population genetic analysis, we more densely sampled this species across its range in California and used low-coverage whole-genome resequencing to identify SNPs for population genetic analysis. We more finely evaluate the substructure present in this species, interrogate the existing taxonomy in the genus, and redefine species boundaries. Our analysis provides a rationale for a morphological revision of the genus to rectify the existing paraphyly of the type species. Results of species distribution modeling using MaxEnt, incorporating WorldClim climactic variables further confirm this species as a moisture-sensitive microhabitat specialist restricted to forested regions in California. This modeling suggests that a gap in the range of U. mordax that has perplexed arachnologists for decades is due to competitive exclusion by another scorpion, Graemeloweus iviei. These genomes and their associated reference also provide the potential for future landscape genetic analysis to examine the effect of major wildfires as barriers to gene flow as well as SNPs associated with environmental features.