Evolution of chemosynthetic community -From the view point of paleoecology-

分析了白垩纪至上新世的化能菌群落，主要包括囊菌。研究结果表明，大型囊虫在白垩纪中没有出现，并在渐新世末和中新世初改变了其属的组成。由于新生代泡囊蝇类常与杯囊蝇类共生，故在白垩纪后侵入杯囊蝇类优势群落。我可以在日本收集最古老的Bathymodiolus物种，并讨论这些贻贝在中新世晚期传播到世界各地，就像大型的vesicomyids一样。另一方面，在整个调查时间间隔内没有观察到群落结构的时间趋势。然而，多样性和生态结构表现出水深的趋势：浅水区的群落表现出较低的均匀度，以及较高的多样性比深水区的群落。此外，具有较高多样性的社区表现出较低的比例的化学共生类群比那些社区与较低的多样性。有人建议，这种深度相关的结构的发展，因为增加深度可能会降低效率的捕食者在调解的社区。

Chemosynthetic communities of Cretaceous to Pliocene age were analyzed, mainly including vesicomyids. As a result of examination, the large vesicomyids did not appear in the Creataceous and changed its generic composition in the end of Oligocene and early Miocene. As the Cenozoic vesicomyids were frequently associated with the thyasirids, it invaded into the thyasirid-dominated communities after the Creataceous. I could collect the oldest species of Bathymodiolus in Japan and discussed these mussels spread world wide in the late Miocene like as the large vesicomyids. On the other hand, temporal trends in community structure were not observed throughout the investigate time interval. However, diversity and ecologic structure showed a bathymetric trend : the shallow-water communities show a lower evenness as well as higher diversity than the deep-water communities. Moreover, the communities with higher diversity showed a lower proportion of chemosymbiotic taxa than those communities with lower diversity. It is suggested that this depth-related structure develops because increasing depth might decrease the efficiency of predators in mediating the communities.