Distributions of a halophilous and a riparian species of harvestmen along Sendai River, Tottori City, with the first records of harvestmen in Tottori Sand Dunes

摘要

Distributions of a maritime harvestman, Psathyropus tenuipes and a riparian harvestman Paraumbogrella pumilio were investigated along the Sendai River, Tottori City, Honshu, Japan. Psathyropus tenuipes was found from the mouth of the river to the site 4 km upstream where slight salinity (0.1 PPT) was detected in the river. On the other hand, no specimens were found from the upstream sites where no salinity was detected.This indicates that the species needs at least a slight salinity for its occurrence. Paraumbogrella pumilio was found at five sites from the dry riverbed near the Shobu floodgate to a site on the right bank of Sendai River just upstream of Yachiyo Bridge. Occurrence of this species seems to be related to presence of open ground covered with lower grasses on the banks. Recently, the both species were also found from the right bank of the river mouth of Sendai River that is also a part of Tottori Sand Dunes. These are the first records of harvestmen from Tottori Sand Dunes.