The geographical distribution of Polycelis (Polycelis) sapporo and Seidlia schmidti in the Far East

Abstract

Polycelis (Polycelis) sapporo (Ijima et Kaburaki, 1916) is a non-stenothermal species, common in Hokkaido (including all of the adjacent islands), Northern Japan, except in the alpine region. It is also distributed in Aomori Prefecture in the northernmost part of Honshu. To the south, its range is bounded by a line from the base of the Tsugaru Peninsula, over Mt. Iwaki, Mt. Shirakami, Mt. Tashiro, Lake Towada, Mt. Hakkoda, the Natsudomari Peninsula, to the west of Mutsu and Ohata in the Shimokita Peninsula. In Russia, the species is recorded only from the southern part of Sakhalin. Seidlia schmidti (Zabusov, 1916) is a stenothermal species found in cold-water biotops. It occurs in the North and East of Hokkaido including the Shiretoko Peninsula and Rishiri Island. In Russia, the species is recorded from the southern part of Sakhalin, Primorskiy, Habarovsk including the base of the Chukotskiy Peninsula, and the Kamchatka Peninsula (and Bering Island).