Paleontological and geochemical study of the molluscan faunas in West Pacific during MMCO

该研究项目旨在通过比较日本和东南亚（菲律宾和印度尼西亚）之间的软体动物化石，阐明中中新世气候最佳时期（MMCO）的西太平洋海洋地理和气候。结果表明，日本和东南亚之间的共同种数量很低（不到5%），这表明每个物种都构成了自己的地理实体。揭示了日本与东南亚之间少数几个共有种之一的莱内甜瓜（Melongena lainei）谱系地理分布的历史变迁。基于双壳类化石同位素分析的MMCO古温度估算是未来的研究方向。

This research project aims to clarify the West Pacific marine biogeography and climate during the Middle Miocene climatic optimum(MMCO) based on the comparison of fossil molluscan faunas between Japan and SE Asia(Philippines and Indonesia). The results include that the species in common between Japan and SE Asia is very low in number(less than 5%), suggesting that each constitutes own biogeographic entities. Historical changes of geographic distribution of the Melongena lainei lineage, one of few species in common between Japan and SE Asia, were revealed. Paleo-temperature estimation based on the isotopic analysis of fossil bivalve during MMCO is a future work.