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Universality and hierarchy in evolutionary pattern-approach from "marine insect" Ostracoda

进化模式的普遍性和层次性——从“海洋昆虫”介形类谈起

基本信息

批准号：
14340155
负责人：
KAMIYA Takahiro
金额：
$ 9.34万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

项目摘要

Evolutionary characteristics of ostracodes ware comprehended through this work. Marine cytheroidean ostrcaodes, which are probably most diversified taxa in ostracodes, are known for its increasing of diversity in Paleogene. The super family is proved to have paedomorphic characters against the other primitive superfamilies such as Bairdoidea and Cythpridoidea. This is seen in the number of pores in carapaces and the number of setae in brachial plates. The results are obtained from the detail observation and description of representatives from each superfamilies through ontogeny. On the other hand, four genera belonging to the superfamily cytheroidea and bairdioidea were especially studied well on the process and timing of the speciation and evolution. They were the genera Loxoconcha, Xestoleberis, Paradoxostoma of cytheroidea and the genus Neonesidea of bairdoidea, and their taxonomiy and geographical distribution were studied in Japan, Philippines and the west coast of North America. The common pattern found in the evolution of these genera lead to the conclusion that the biodiversity of related species are extgremely high around Japan compared with other areas in the world. These related species are living separately in Pacific, Sea of Japan, Okhotsk Sea and cold Oyashio areas, which corresponds to the currents and/or marine climatic divisions. The reason of this fact may be because the glacial eustatic sea level changes in the Quaternary caused the isolation of the marginal seas, and eventually a natural selection for the mutation which was able to adapt to the cold climate during glacial ages. As mentioned above, through this study, the evolutionary model which can be applicable to the isolated marginal sea area was first acquired.

通过这项工作，我们了解了介形类动物的进化特征。海洋甲壳类动物是甲壳类动物中最多样化的一类，其多样性在古近纪逐渐增加。证明该超科与其他原始超科（如bairdo总科和cythprido总科）相比具有童胚性。这可以从甲壳上的气孔数量和臂板上的刚毛数量中看出。结果是通过个体发生对每个超科的代表进行详细观察和描述而得出的。另一方面，对cytheroidea和bairdioidea超科的4个属的形成和演化过程和时间进行了深入的研究。分别为cytheroidea中的Loxoconcha属、Xestoleberis属、Paradoxostoma属和bairdoidea中的Neonesidea属，对其在日本、菲律宾和北美西海岸的分类和地理分布进行了研究。在这些属的进化中发现的共同模式使我们得出结论，与世界其他地区相比，日本周围的相关物种的生物多样性非常高。这些有亲缘关系的物种分别生活在太平洋、日本海、鄂霍次克海和寒潮地区，与海流和/或海洋性气候区相对应。其原因可能是第四纪冰川海平面的上升引起了边缘海的隔绝，最终形成了适应冰期寒冷气候的突变体的自然选择。如上所述，通过本研究，首次获得了适用于孤立边缘海域的演化模型。