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。日本已发现淡水海绵11属25种。海绵被称为滤食性动物，它们吃细菌或碎屑，并通过保留这些颗粒来清洁周围的水。海绵可以生活在相当肮脏的水中，但超过一定程度的污染就会迅速灭绝。我们的调查主要是在琵琶湖（琵琶湖）的35点和新次子湖（新次子）的10点进行的。A) Biwa-ko：以下是项目期间在Biwa-ko收集的8属11种淡水海绵。1. 海绵动物同温层海绵虫；易碎的厄纳皮乌斯4。叶苔；叶黄；7.异源性失眠症；多齿异角蕨；九。水蛭（trochosponilla philottiana）放射子…更多的小脑脊。除inarmata海绵虫1种外，其余4种均为新发现种，分别为fluviatilis、T. philottiana、T. latouchiana和H. multidentata。在分布方面，据报道，琵琶湖特有种S. clementis遍布全湖，但在调查中仅在北湖发现，北湖的水是琵琶湖最干净的。在南湖和北湖城市附近，有丰富的Eunapius属、E. muelleri属和E. japonica属，而这些物种在湖的东北部很少发现。B)新地子及其附近地区：在新地子进行了两次调查，这是一个咸淡水湖泊。在这些湖泊中只分布有白海绵，即咸淡水海绵。在新枝谷，海绵的分布在很大程度上取决于海水的盐度。在新枝海（盐度3.0% ~ 0.6%_0）中只发现了S. alba。在船川，即使在淡水地区（盐度0.5%_0 ~ 0.2%_0），也有白藻分布。在船川海域，采集到4只真淡水海绵和白藻。这表明白藻适应的盐度范围很广，从咸淡水到淡水。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