New species in old mountains: integrative taxonomy reveals ten new species and extensive short-range endemism in Nesticus spiders (Araneae, Nesticidae) from the southern Appalachian Mountains

This revision is based on sampling efforts over the past three decades in the southern Appalachian Mountains which have provided Nesticus (Araneae, Nesticidae) collections of approximately 2100 adult specimens from more than 475 unique collecting events. Using a “morphology first” framework we examined recently collected specimens plus museum material to formulate morphology-based species hypotheses for putative new taxa (discovery phase). Using sequence capture of nuclear ultraconserved elements (UCEs) we analyzed 801 nuclear loci to validate new (and prior) morphology-based species hypotheses (validation phase) and reconstructed a robust backbone phylogeny including all described and new species. Sanger sequencing and UCE-bycatch were also used to gather mitochondrial data for more than 240 specimens. Based on our integrative taxonomic framework ten new Nesticus species are herein described, including N.binfordaesp. nov., N.bondisp. nov., N.caneisp. nov., N.cherokeensissp. nov., N.dellingerisp. nov., N.dykemanaesp. nov., N.jemisinaesp. nov., N.lowderisp. nov., N.roanensissp. nov., and N.templetonisp. nov. Previously unknown males are also described for N.bishopi Gertsch, 1984, N.crosbyi Gertsch, 1984, and N.silvanus Gertsch, 1984, as well as the previously unknown female for N.mimus Gertsch, 1984. Based on combined evidence N.cooperi Gertsch, 1984 is placed in synonymy with N.reclusus Gertsch, 1984. Overall, the montane radiation of Appalachian Nesticus reveals a general lack of species sympatry and compelling biogeographic patterns. Several regional Nesticus taxa are rare, microendemic habitat specialists that deserve conservation attention and detailed future monitoring as conservation sentinels.