Spiders of the Hidaka Mountain Range, Hokkaido, Japan

Abstract

The spider fauna of Mt. Daisetsu was investigated in 1970 as a project of JIBP-CT-S section, and fairly many spiders were brought to light. However, nothing has hitherto been known on the spider fauna of the Hidaka mountain range. Fortunately, the author had an opportunity to examine the spiders collected by Dr. J. AOKI, Dr. S.-I. UENO and other zoologists during the surveys of Mt. Poroshiri-dake and Mt. Petegari-dake. Materials handed over to the author for identification include about 200 individuals, which were classified into 37 species of 25 genera belonging to 13 families. Of these, six species were recognized as being new to science; three others were newly added to the fauna of Hokkaido, i.e. Theridion chikunii YAGINUMA, Prolinyphia marginella OI and Xysticus atrimaculatus BOESENBERG et STRAND. Some species of Micryphantidae and Salticidae are still awaiting further investigation, because many of them are either immature of represented by a single sex. Pellenes ususudi has long been called under the name of Plexippus incognitus, whose real nature is uncertain. The author has carefully re-examined this spider and described it as a new species at this opportunity. Though the spiders taken in this survey are not numerous, most of them are common to Mt. Daisetsu. One-fourth of these species are either Palaearctic of Holarctic, and the remainings are Japanese basic species distributed in the northern parts of Japan.