Species diversity of cryophilic marine ostracods; the history clarified by fossil records

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K06390
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45030:Biodiversity and systematics-related
• Research Institution: Nihon University
• Principal Investigator: OZAWA Hirokazu 日本大学, 生物資源科学部, 准教授 (20632045)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 生物多様性 / 貝形虫 / 分類 / 系統 / 新生代 / 北西太平洋 / 環境変動 / 化石

Outline of Final Research Achievements

This research is studying marine cryophilic ostracods (crustacea) living in and around Japanese Islands. This study is trying to clarify their suitable living conditions for present habitats, the history from their birth to flourishing, places of the birth and flourishing, key factors of environmental changes for their diversifying process, with estimates for the phylogenetic relationship among plural species for two families. Furthermore this research will clarify the primary cryophilic fauna in the northwestern Pacific margin and the history of taxonomic diversity changes. For the last three years, this study obtained the basic data to be able to infer periods of the birth and environmental conditions of their habitats, with the
estimation for phylogenetic relationships based on pore distributional pattern on carapace for one genus of one family. We will represent these data on scientific journals and talks in academic meetings in domestic and international congress near future.

Free Research Field

古生物学、古環境学

Academic Significance and Societal Importance of the Research Achievements

本研究は北西太平洋縁の新生代の好冷性生物の初期相と、分類学的多様性変遷史の解明を目指して解析を行った。特に400万年前以降は好冷性海生動物群の初期生物相が形成された重要な時期であるが、日本産海洋生物でその時期と前後の生物相変化について、科・属内レベルで種数変遷や種交代、種間の系統関係を古環境変動史も総合して詳しく論じた研究例はほとんど無い。そのためこのテーマについて研究する意義は大きい。また複数の新生代の地層産貝形虫化石群の解析に基づき、古海洋環境と変動史を検討した。これらは、日本列島沿岸で特に環境変動の激しかった、新生代の中新世以降の生物多様性変遷と海洋環境変動を解明する上で重要である。