Abstract
Spiders of the genus Cybaeus are diverse in Japan and exhibit extensive morphological variation of their genitalia among species. Among Japanese Cybaeus, several species possess an elongated embolus in males and elongated spermathecae in females. Here, we describe Cybaeus iharai sp. nov. from Nagano Prefecture, central Honshu, Japan, which possesses a short embolus in males and short copulatory ducts in females. In addition, DNA sequences of the new species were obtained for future phylogenetic analyses.