青森県中部(黒石市, 櫛ケ峯及び大鰐地域)の淡水産ブラナリアの生態調査報告

The vertical distribution of freshwater planarians in Kuroishi City, the Mt. Kushi-gamine district in the Towada National Park and in the Owani district (Lat. 40°20′N. to Lat. 40°40′N. and Long. 140°25′E. to Long. 141°00′E.), all in the central part of Aomori Prefecture, Honshu, was surveyed. Mt. Kushi-gamine (altitude, 1517m) is one of the main peaks of the Minami-Hakkoda mountains. The main river systems in the area surveyed are the Oirase, the Aseishi (a large tributary of the Iwaki River), the Hirakawa (a tributary of the Iwaki River) and the Shimouchi (the Yoneshiro River ; the upper course of the Noshiro River). Based upon the previous report (KAWAKATSU, TBSHIROGI & YAGIHASHI 1967), the distribution of freshwater planarians on the south-eastern slope of Mt. Iwaki was also surveyed. The surveys were made in 1966 and 1967. In the area surveyed, the following eight species of freshwater planarians were found : Dugesia japonica ICHIKAWA et KAWAKATSU, Phagocata vivida (IJIMA et KABURAKI), Phagocata teshirogii ICHIKAWA et KAWAKATSU, Phagocata sp., Polycelis auriculata IJIMA et KABURAKI, Bdellocephala brunnea IJIMA et KABURAKI, Bdellocephala sp. and Dendrocoelopsis lacteus ICHIKAWA et OXUGAWA. D. japonica was found to be common at many localities of the plains and the mountainous areas. This species was found at the stations below the altitude of about 480 metres (inhabitable water temperature range, 1.0〜25.0℃). In the area surveyed, Ph. vivida and Pol. auriculata were distributed widely. Ph. vivida found at the stations within the altitude range of about 40 to 920 metres (2.0〜20.0℃). Pol. auriculata was found at the stations within the altitude range of 120 to 1280 metres (4.5〜19.0℃). The type of the vertical distribution in the area surveyed is J-JV-JVA-VA-A (J : D. japonica ; V : Ph. vivida ; A : Pol. auriculata). Ph. teshirogii and Bd. brunnea were found in some springs and spring-fed streams in the plains. Phagocata sp. and Bdellocephala sp. were found at some localities in the Tsutanana-numa district in the Towada National Park. Den. lacteus had been found only in Hokkaido in North Japan. Large populations of this species were found in the vicinity of Kuroishi City (an orchard of apples at Rokumantai) and at some localities in the Mt. Iwaki district in Aomori Prefecture. In the Rokumantai district, Den. lacteus was found to be common in many springs, brooks and in shallow streams fed by the thawing of anow (altitude, 150〜340m). This is the first record of occurrence of this species in Honshu.