Natural history of amphidromous gastropods

2014 Fiscal Year Final Research Report

• Project/Area Number: 24770072
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Biodiversity/Systematics
• Research Institution: The University of Tokyo
• Principal Investigator: KANO Yasunori 東京大学, 大気海洋研究所, 准教授 (20381056)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 両側回遊 / 軟体動物 / 腹足類 / 幼生 / 河川 / 生物地理 / 熱帯 / 国際研究者交流

Outline of Final Research Achievements

The natural history of neritid and thiarid gastropods was studied for understanding the role and importance of amphydromy in freshwater ecosystems on coastal and oceanic islands. Our comprehensive, well-supported molecular phylogeny of the former family not only confirmed repeated invasions of freshwater by marine ancestors but also suggested multiple reinvasions of the sea from limnic habitats. A plausible explanation for such unusual reversal in habitat shifts is the ontogenetically euryhaline nature of amphidromous animals. Re-classification of the IWP species based on shell morphology and mitochondrial COI sequences revealed that most amphidromous taxa have very small intraspecific variation throughout their wide-ranging distributions that often span several thousand kilometers. Species richness peaks in the Coral Triangle and declines with increasing distance from this region, both latitudinally and longitudinally, corresponding with the pattern for shallow marine animals.

Free Research Field

進化学・生態学