Process of species diversification in fossil records of land snails on remote islands

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H03743
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Tohoku University
• Principal Investigator: Chiba Satoshi 東北大学, 東北アジア研究センター, 教授 (10236812)
• Research Collaborator: HIRANO Takahiro ; MORII Yuuta ; Prozorova Larisa ; SUZUKI Takanori
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 進化 / 海洋島 / 生物地理 / 更新世 / 適応放散

Outline of Final Research Achievements

A rapid morphological and ecological divergence was documented in the fossil records ofland snails in the Pleistocene and Holocene deposits on the Ogasawara Islands.　However, such rapid divergence is not found in the fossil snail sequences in the Ryukyu Islands (e.g. Kikai Island). Molecular phylogenetic analyses and ecological surveys showed consistent relationships among morphology, ecology and phylogeny were found in Ogasawara, Ryukyu, and mainland lineages, but rapid ecological and species divergence are limited to the snails of Ogasawara. These patterns are consistent with those detected in the fossil records. Divergence of habitat use promoted by competitive interaction appears to be a major process of speciation and radiation on oceanic islands, while speciation on mainland occurs by adaptation against predation as well as geographic isolation.

Free Research Field

生態学