The ecological and taxonomical study on the living ostracods from coral reefs in the Sckisci-sho area, Ryukyu Islands, Japan

本研究的目的是揭示琉球群岛关城町地区珊瑚礁中介形类物种的生态分布，并对未描述的物种进行系统的描述。1990年9月，通过潜水从10个地点(约3~15米深)、5个泻湖地点和5个礁坡地点采集了30个活的介形类标本。结果共鉴定出斑潜蝇40属76种，斑潜蝇2种。根据常见的30种足足类的分布格局，可以划分出与底质种类有关的3个物种组：第一类与砂底关系密切，第二类几乎局限于岩石、砾石等坚硬底层的大型或丝状微藻，第三类与特定底质关系不明显。第一类和第二类的物种组成各有不同，这取决于砂底的粒度分布和大型藻类以及丝状藻类生长的岩石或砾石的形状。根据周围水团的性质，一些物种的丰度也不同，例如海洋或泻湖。对超过50种未描述物种的分类工作仍在进行中。在本研究中，附属物和雄性性器官等通常不作为化石保存的软体部分也被用作甲壳的重要分类特征。

The purpose of this study is to reveal the ecological distributions of ostracod species from coral reefs in the Sekisei-sho area, Ryukyu Islands, and to carry out the systematic descriptions on the undescribed species. In September, 1990, 30 samples for living ostracods were collected by SCUBA diving from 10 locations (about 3 to 15 meters deep); 5 locations in the lagoon and 5 in the reef slope. As a result, 76 species belonging to 40 genera of Podocopa and 2 species of Myodocopa were identified. Based on the distribution patterns of 30 podocopid species occurring frequently, three species groups in relation to the kinds of substrates can be distinguished; the first group appear in close relation to sand bottom, and the second is almost confined to macroalgae or filamentous minute algae on hard bottom such as rocks or gravels, and the third have no distinct relation to particular kinds of substrates. The species composition of the first and second groups are respectively variable to some extent, depending on the grain size distribution of sand bottom and the shape of macroalgae and rocks or gravels on which filamentous algae grow. Some species also differ in abundance depending on the nature of surrounding water mass such as oceanic or lagoonal. Taxonomical work on undescribed species over 50 are still ongoing. In this study, soft parts such as appendages and male sexual organs, which are not usually preserved as fossils, are also used as important taxonomical characters with carapace.