Comparative developmental studies on the evolution of marine invertebrate larvae using non-model animals

2018 Fiscal Year Final Research Report

• Project/Area Number: 26711022
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Biodiversity/Systematics
• Research Institution: University of Tsukuba
• Principal Investigator: Nakano Hiroaki 筑波大学, 生命環境系, 准教授 (70586403)
• Project Period (FY): 2014-04-01 – 2019-03-31
• Keywords: 珍渦虫 / 珍無腸動物門 / 平板動物 / 海産無脊椎動物 / 左右相称動物 / 後生動物 / 幼生 / 進化

Outline of Final Research Achievements

The aim of this study was to uncover the evolution of marine invertebrate larvae by performing comparative developmental studies on so called non-model organisms. Another related aim was to obtain fundamental biological data on these organisms to enable developmental research.
Concerning Xenoturbella, a new species (sixth xenoturbellid species) was reported from Japan. The need for reconsideration of the phylogenetic position of Xenoturbella was suggested from new phylogenomic analyses. Additionally, a new species of orthonectids that parasitizes xenoturbellids was reported, with implications on the effects on the reproduction of its host being discussed.
Concerning placozoans, their breeding season was identified and embryos were obtained. A new collection method established during this study was used for collecting placozoans from new sites around Japan and phylogeographic analyses were performed.

Free Research Field

系統進化学

Academic Significance and Societal Importance of the Research Achievements

本研究では、これまであまり研究がされてこなかった動物の採集法の開発、成体・幼生の飼育法の確立、成体の形態学的観察などを行うことで、新種の記載、新しい器官の発見、繁殖時期の解明など大きな成果が得られ、これらの基礎的な、古典的な実験や研究の重要性が示された。また、本研究で新種が報告されたことから、まだまだ人類に発見されていない生物種が数多く存在することが示唆され、今後の生物多様性や系統分類学的研究の発展が待たれる。今後は、本研究で用いた種も含め、これまであまり研究がさかんでなかった種を研究することで、その幼生形態も含め、動物の進化過程に関して新たな知見を得ることが期待される。