Freshwater sponges in Japan ; systematics and distribution

本研究的目的是调查淡水海绵在其栖息地的种类，并明确其分布与环境的关系。据报道，日本有淡水海绵11属25种。海绵被称为滤食动物，它们以细菌或碎屑为食，通过滞留这些颗粒来净化周围的水。海绵可以生活在相当脏的水中，但在一定程度的污染后很快就会灭绝。本次调查主要在琵琶湖(琵琶湖)的35个点和真基湖(真基湖)的10个点进行。1.乳状海绵2.层旋藻3.脆弱真螺旋藻4.马氏海绵5.日本异尖线虫6.多齿异尖线虫7.多齿异尖线虫8.水生异尖线虫9.喜氏轮虫10.拉图奇亚轮虫11.Radiospon…更多的小脑吉拉。除1种为Inarmata外，其余均为新发现种，另有4种为新发现种：河海绵、水生海绵、拉氏海绵和多齿海绵。在分布方面，据报道，琵琶湖特有物种Clementis分布于全湖，但在调查中仅在琵琶湖水质最干净的北湖发现。在南湖和北湖城市附近，Eunapius属、E.muelleri属和Eunaponica属丰富，这些物种在湖的东北部很少发现。2)新记湖及其附近：在新记湖进行了两次调查，这些都是咸水湖泊。在这些湖泊中，只分布着一种微咸水海绵--白海绵。在新济科，海绵的分布在很大程度上取决于海水的盐度。在盐度为3.0%~0.6%的新池中，只发现了白沙门氏菌。在Funakawa，即使在淡水区(盐度为0.5%~0.2%0)，也分布着白纹伊蚊。在Funakawa，采集了4个真正的淡水海绵以及S.alba。这表明白纹藻适应了从微咸水到淡水的广泛盐度。较少

It is the purpose of this research to survey the species of the freshwater sponges in their habitats and to make clear the relation between their distribution and environment. Eleven genus and 25 species of freshwater sponges have been reported in Japan. Sponges are known as filter feeders which eat bacteria or detritus and clean up the ambient water by retention of these particles.Sponges can live in rather filthy waters, but become extinct rapidly excess some degree of pollution. Our survey was done mainly at 35 points of the Lake Biwa (Biwa-ko) and the 10 points of the Lake Shinji (Shinji-ko).A) Biwa-ko : The followings are the 11 species of 8 genus and of freshwater sponges collected in Biwa-ko during the term of the project. 1. Spongilla lacstris 2. Stratospongilla clementis 3. Eunapius fragilis 4. Ephydatia muelleri 5. Ephydatia japonica 6. Heteromeyenia stepanowii 7. Heterorotula multidentata 8. Ephydatia fluviatilis 9. Trochospongilla philottiana 10 T. latouchiana 11. Radiospon … More gilla cerebellata. The previously reported species were all found except one, Spongilla inarmata, besides 4species were newly found in the Lake, E. fluviatilis, T. philottiana, T. latouchiana and H. multidentata. Concerning the distribution, S. clementis, the endemic species of the Biwa-ko, was reported to be distributed in all over the lake, but in the survey they were found only in the North Lake, whose water is the cleanest in the Biwa-ko. In the South Lake and near the cities of the North Lake, the genus of Eunapius, E. muelleri and E. japonica were rich, and these species were scarcely found in the northeast part of the lake.B) Shinji-ko and its vicinity : Surveys were done twice in Shinji-ko and which are brackish water lakes. In these lakes only Spongilla alba, the brackish water sponge, was distributed. At Shinji-ko, the distribution of the sponges deeply depends on the salinity of waters. In the Shinji-ko, (salinity 3.0%_0 to 0.6%_0), only S. alba was found. In the Funakawa, even in the freshwater area (salinity 0.5%_0 to 0.2%_0), S. alba was distributed. In the Funakawa, 4 true freshwater sponges were collected as well as S. alba. This shows that S. alba adapts to wide range of salinity, from brackish waters to fresh waters. Less