Challenging for an origin of eye and vision of ancient animals

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K05592
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Kanazawa University (2017-2018); Kumamoto University (2016)
• Principal Investigator: Tanaka Gengo 金沢大学, GS教育系, 助教 (50437191)
• Co-Investigator(Kenkyū-buntansha): 前田 晴良 九州大学, 総合研究博物館, 教授 (10181588)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 眼の化石 / カンブリア紀 / 保存の良い化石 / 複眼 / カメラ眼 / ノープリウス眼 / 単眼 / 先カンブリア時代

Outline of Final Research Achievements

The origin of the eye can be traced back to the Cambrian. At the moment, the oldest fossil of the eye is the compound eye of the trilobite about 525 million years ago. We investigated the fossil localities of the older age, but we could not find organisms with eyes. We were able to identify to some extent potential sites for the fossils with eyes on the Early Cambrian strata.
Regarding Ordovician and Devonian trilobites, CT scan was performed using well-preserved fossils, three-dimensional coordinates were acquired, the optical axis of each individual eye was determined, and then the field of view was estimated. The Ordovician trilobite, which is considered to be pelagic, can be estimated to have a wide field of view and live near the surface. On the other hand, the shallow-sea Devonian trilobite had a high resolution eye, though the vertical field of view was extremely narrow.

Free Research Field

古生物学

Academic Significance and Societal Importance of the Research Achievements

眼がいつ誕生したのかについては、分子生物学や古生物学から、程度推定されている。しかし、化石に遺された眼については、推定値よりかなり若返ってしまう。本研究は最古の眼の化石について、発見こそできなかったが、有力な化石産地を絞りこむことに成功した。また、オルドビス紀の三葉虫やデボン紀の三葉虫について、視野や眼の解像度を定量的に推定することができた。これらの手法を用いることで、絶滅生物の視界が復元できる。