Data from: Phylogenomics of paleoendemic lampshade spiders (Araneae, Hypochilidae, Hypochilus), with description of a new species from montane California

<p>The spider genus <em>Hypochilus</em> is a relictual lineage of Nearctic species distributed disjunctly across the United States in three montane regions (California, southern Rocky Mountains, southern Appalachia). Phylogenetic resolution of species relationships in <em>Hypochilus</em> has been challenging, with different data types recovering sometimes conflicting topologies. Furthermore, conserved morphology coupled with extreme genetic divergence and paraphyletic topologies at the species level has led to uncertain species limits in some complexes. Using a combination of ultraconserved elements (UCEs), mitochondrial CO1 by-catch, and studies of morphology, we have reconstructed <em>Hypochilus</em> interspecies relationships and have more critically evaluated the possibility of cryptic species in California and in southern Appalachia. Phylogenomic data from hundreds of nuclear loci strongly support the monophyly of regional clades, and furthermore support a ((California, Appalachia), southern Rocky Mountains)) topology. We hypothesize late Cenozoic age divergences in North America, but acknowledge that more research is needed to reliably date divergences in this genus. Within the southern Appalachian fauna, five species are resolved as four lineages (<em>H. thorelli</em> Marx, 1888 and <em>H. coylei</em> Platnick, 1987 are clearly sister taxa), but the interrelationships of these four lineages remain unresolved despite phylogenomic-scale data. The Appalachian species <em>H. pococki</em> Platnick, 1987 is recovered as monophyletic, which differs from prior mitochondrial evidence, but is clearly highly genetically structured at the nuclear level. Although algorithmic analyses of the nuclear data indicate many species (e.g., all populations as species), scanning electron microscopy (SEM) surveys of male morphology instead reveal striking morphological stasis, clearly illustrating the cryptic species problem. Within the California clade, nuclear and mitochondrial lineages of <em>H. petrunkevitchi</em> Gertsch, 1958 correspond directly to drainage basins of the southern Sierra Nevada, with <em>H. bernardino</em> Catley, 1994 nested within <em>H. petrunkevitchi</em> and sister to the southernmost basin populations. Again, algorithmic analyses of nuclear and mitochondrial data suggest many species, but we take a more conservative approach, allowing for population genetic structure within species. Combining nuclear, mitochondrial, geographic and morphological evidence we describe a new species from the Tule River and Cedar Creek drainages, <em>Hypochilus</em> <em>xomote</em> sp. nov. We also emphasize the conservation issues that face several microendemic, habitat-specialized species in this remarkable genus.</p>