2021 Volume 70 Issue 1 Pages 25-28
Robertus nipponicus Yoshida 1995 (Araneae: Theridiidae) was described using a male specimen collected from Kumamoto Prefecture, Japan, and additional specimens, including females, have never been obtained since the original description. In this paper, we described the female of R. nipponicus for the first time, using specimens collected from Kochi Prefecture, Japan. Females of this species can be distinguished from those of the congeners, R. sibricus Eskov 1987, R. ussuricus Eskov 1987, and R. mediterraneus Eskov 1987, by the narrow, transversely longer, and inverted v shaped copulatory openings. We also provided additional morphological information of the male.