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

本研究旨在通过对日本和东南亚（菲律宾和印度尼西亚）软体动物化石区系的比较，厘清中中新世气候最适期（MMCO）西太平洋海洋生物地理和气候。结果表明，日本和东南亚共有的物种数量很少（不到5%），表明它们各自构成了自己的生物地理实体。揭示了日本与东南亚之间少数共同种Melongena laainei世系地理分布的历史变化。基于双壳类化石同位素分析的古温度估算是未来的工作方向。

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.