抄録
The distributions of eight crab species belonging to five genera in the families, Hymenosomatidae, Pilumnidae and Varybudae, were studied on the basis of 1390 specimens collected in 2003 and 2004 from brackish waters in the rivers and estuaries in Kochi Prefecture, in southern Japan. Halicarcimus messor (Hymenosomatidae), Pilummopeus marginalus(Pilunnidae) and Phychoganthus capillidigitatus (Varunidae) were recorded for the first time in the Kochi Prefecture. A total of 192 specimens confirmed the widespread occurrence of Neorhynchoplax okinawaensis (Hymenosomatidae) in the study area. Prior to this study only five individuals of N. okinawaensis had been recorded as Halicarcinus orientalis from Urado Estuary, in Kochi City. Pilumnopeus makianus and Phychognathus ishii were common species in this estuary, but the precies distributions of these species were unknown prior to this study, Specimens of two varunid species, Acmaeopleura toriumii and A. parvula, were also collected. The presence of these species suggested that the brackish water crab fauna in the present study area contained rare Japanese species, that were similar to those found on the western coast of the Kii Peninsula.
