Origin of establishment of symbiotic relationship between radiolarians and the symbionts and evolution of the shell components based on the molecular phylogeny and the ultrastructural observations.

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05326
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Tokyo Gakugei University
• Principal Investigator: TAKAHASHI Osamu 東京学芸大学, 教育学部, 准教授 (20242232)
• Co-Investigator(Renkei-kenkyūsha): MAYAMA Shigeki 東京学芸大学, 教育学部, 教授 (40199914) ; MATSUOKA Atsushi 新潟大学, 理学部, 教授 (00183947) ; TAKEMURA Akihiro 琉球大学, 理学部, 教授 (40222103)
• Research Collaborator: Bjørklund K. R. オスロ大学
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 放散虫 / 共生 / 系統解析 / 渦鞭毛藻 / ハプト藻 / 緑藻 / 遊走子 / リプロダクション

Outline of Final Research Achievements

SEM, TEM and molecular phylogenetic analysis were carried out confirming the reproductive stages of some polycystines and acantharean radiolarian species. We concluded that the radiolarian swarmer size is several micrometers. Those are smaller than the size of their symbiotic algae and it is impossible to get the symbiotic algae in the sexual reproduction. In addition, at least four kinds of symbionts, haptophyte, dinoflagellates, green algae and cyanobacteria have been confirmed in radiolarians, and this time we described Gymnoxantella radiolariae as a new species of dinoflagellate in symbiosis with radiolarians. It suggests that radiolarians are selected out from the environment after being adulted and acquire symbionts in situ in the same area.

Free Research Field

地質学