SYSTEMATICS, PHYLOGENY AND ZOOGEOGRAPHY OF GENUS YORAPERLA (PLECOPTERA, PELTOPERLIDAE)

Yoraperla Ricker, 1952 is revised and 4 nearctic and 3 oriental specie s are recognized. Three new species, Y. siletz, Y. han and Y. uchidai, are described and Y. nigrisoma (Banks, 1948) is removed from the syno nymy of Y. brevis (Banks, 1907). Phylogenetic and zoogeographic analys es support the hypothesis of two disjunct clades isolated by an increa se in sea level in the Bering Straits. The east Asian clade is consist ently reserved with the two Korean species Y. han and Y. uchidai formi ng a sister group relationship apart from the Japanese species Y. ueno i, while resolution of the western North American clade is less secure . Yoroperla probably arose in the Sierra Nevada of North America and m igrated to east Asia along an inland route including the Rocky Mts. Fu ture collection and conservation suggestions are given.