A Remarkable New Species of <i>Arcuphantes</i> (Araneae: Linyphiidae: Micronetinae) from Northeastern Shikoku, Japan, with Observations on Mating Behavior and Preliminary Molecular Analysis

A remarkable new species of the genus Arcuphantes Chamberlin and Ivie, 1943 characterized by conspicuous genital morphology, is described from northeastern Shikoku, Japan, based on both sexes, under the name of A. bandoi n. sp. The new species is distinguished by an extremely elongated, looped scape of epigyne with S-shaped undulation and a paracymbium of the male palp extending to the distal end of the cymbium. Arcuphantes bandoi n. sp. is known only from the vicinity of four rivers and their associated tributaries located north of the Yoshino-gawa River basin, within an area measuring approximately 6.0 km × 8.0 km. At the periphery of this region, the new species exhibits a non-strict parapatric distribution with Fusciphantes iharai (Saito, 1992). This paper provides a detailed description of the new species including its mating behavior and the male-female genital interaction, comparisons with other species of Arcuphantes and Fusciphantes Oi, 1960 in northeastern Shikoku, and a preliminary molecular analysis.