Taxonomic identification of spider species from morphological structures has limitations in cases of closely related species or intraspecific variability. We investigate the utility of genetic barcoding with the mitochondrial marker cytochrome c oxidase I (COI) in ghost spiders of the subfamily Amaurobioidinae. Most discrepancies between DNA barcoding and morphological identification are explained by low geographic sampling or by geographically structured lineages. In addition, we show that the marker COI is phylogenetically informative for deeper nodes in the tree. (Image credit: Martín Ramírez.)

The epigean and subterranean spider genus Cybaeus is highly species rich in the Japanese Archipelago. The Japanese Cybaeus spiders are classified into ~100 species, but their phylogeny is unclear. We conducted molecular phylogenetic analyses and divergence time estimation based on 73 species and demonstrated that several Cybaeus species should be classified into other genera. Divergence dating suggested that the opening of the Sea of Japan c. 20 million years ago may have promoted diversification and speciation of Japanese cybaeids. (Image credit: Yoh Ihara and Takafumi Nakano.)