Integrative taxonomy of the primitively segmented spider genusGanthela(Araneae: Mesothelae: Liphistiidae): DNA barcoding gap agrees with morphology

Species delimitation is difficult for taxa in which the morphological characters are poorly known because of the rarity of adult morphs or sexes, and in cryptic species. In primitively segmented spiders, family Liphistiidae, males are often unknown, and female genital morphology–usually species-specific in spiders–exhibits considerable intraspecific variation. Here, we report on an integrative taxonomic study of the liphistiid genus Ganthela Xu & Kuntner, 2015, endemic to south-east China, where males are only available for two of the seven morphological species (two known and five undescribed). We obtained DNA barcodes (cytochrome c oxidase subunit I gene, COI) for 51 newly collected specimens of six morphological species and analysed them using five species-delimitation methods: DNA barcoding gap, species delimitation plugin [P ID(Liberal)], automatic barcode gap discovery (ABGD), generalized mixed Yule-coalescent model (GMYC), and statistical parsimony (SP). Whereas the first three agreed with the morphology, GMYC and SP indicate several additional species. We used the consensus results to delimit and diagnose six Ganthela species, which in addition to the type species Ganthela yundingensis Xu, 2015, completes the revision of the genus. Although multi-locus phylogenetic approaches may be needed for complex taxonomic delimitations, our results indicate that even single-locus analyses based on the COI barcodes, if integrated with morphological and geographical data, may provide sufficiently reliable species delimitation.