Abstract
The longiscapus group in the genus Arcuphantes (Linyphiidae) is revised based on genital morphology and geographic distributional pattern. This group should be treated as a closely related species group or a single superspecies by their morphology and distribution. Three known species, A. longiscapus, A. hibanus and A. iharai, and five new species, A. saitoi, A. setouchi, A. tsurusakii, A. nojimai and A. okiensis are described. These eight species are only distributed in western Honshu, northeastern Shikoku and some adjacent islands, Japan. It gives parapatric pattern to the distribution except for some cases of narrow overlap. Morphological correspondence between male palp and epigynum was found as a species-specific character.
