Redescription of Utaperla orientalis (Plecoptera, Chroloperlidae) from Hokkaido: the first record of a Utaperla stonefly in Japan

Taxonomical and ecological knowledge of stoneflies (Order: Plecoptera) is important biological indicator of riverine environments. A genus Utaperla was established by Ricker in 1952 when he described U. sopladora Ricker 1952. The Utaperla stoneflies have been recorded in North America, Russia and China and consists of the species, U. sopladora, U. orientalis Nelson and Hanson 1969, U. lepnevae (Zhiltzova 1970), U. gaspesiana Harper and Roy 1975. None of these species were previously observed in Japan. We recently discovered adult specimens of U. orientalis during a survey of riverine benthos in Hokkaido, Japan, and report here on their collection sites, morphological characteristics, genetic information, and adult emergence patterns in comparison with other sympatric species. Although their abundance appeared to be low, with an emergence period limited to early summer, this finding contributes to an improved database for biodiversity conservation in the region.