A New Stygobitic Species of the Genus Pseudocrangonyx (Crustacea: Amphipoda: Pseudocrangonyctidae) from Central Honshu, Japan

Abstract

A new species of pseudocrangonyctid amphipod, Pseudocrangonyx uenoi, is described from cave streams in Taga town, central Honshu, Japan. Previous molecular phylogenetic studies reported the taxonomic status of the Taga populations of Pseudocrangonyx as an undescribed species. We present the diagnostic features to discriminate P. uenoi from the other congeners on the basis of morphological study. Pseudocrangonyx uenoi is closely related to P. daejeonensis Lee, Tomikawa, Nakano, and Min, 2018, but clearly distinguished from the latter by the presence of calceoli on female antenna 2, the 5-dentate lacinia mobilis of the left mandible, setation of the peduncular articles of pleopods, the number of articles of rami of the pleopods, a shorter terminal article of uropod 3, and a telson with a deeper cleft.