瑞典隆德大学Johan Lindgren小组的研究发现，化石昆虫眼睛能在三叶虫光学和节肢动物色素屏幕上发光。相关论文发表在2019年9月5日出版的《自然》上。

研究团队报告了5400万年前大蚊（crane-fly）眼睛的详细分子组成和显微解剖学，为解释其他一些古代节肢动物的光学系统提供了一个参考。这些保存完好的视觉器官，包括钙化的角膜透镜，其由含有真黑素色素的中间空间隔开。此外，研究还发现真黑素存在于大蚊的小突壁中，它在含有几丁质角膜的复眼中形成最外层的全素体色素屏障。据悉，这是关于节肢动物黑色素筛选色素的首个记录，这揭示了昆虫眼中的化石模式，包括抗腐烂的生物色素和全眼球的早期成岩矿化作用。最初几丁质的晶状体角质层的可证实的二次钙化对所提出的三叶虫角质层角膜有影响，研究者认为这是保存的假象，而不是体内生物矿化的产物。虽然三叶虫眼可能已经部分矿化以获得机械强度，但有机成分更有可能会通过梯度折射率增强光学功能，并加强对透镜形状的控制。

研究人员表示，眼睛化石可以推断出已经灭绝的节肢动物的视觉能力。然而，由于分类学和成岩作用而产生的结构和/或化学变化可以改变原始特征，有必要与现代物种进行比较。

附：英文原文

Title: Fossil insect eyes shed light on trilobite optics and the arthropod pigment screen

Author: Johan Lindgren, Dan-Eric Nilsson, Peter Sjvall, Martin Jarenmark, Shosuke Ito, Kazumasa Wakamatsu, Benjamin P. Kear, Bo Pagh Schultz, Ren Lyng Sylvestersen, Henrik Madsen, James R. LaFountain, Carl Alwmark, Mats E. Eriksson, Stephen A. Hall, Paula Lindgren, Irene Rodrguez-Meizoso, Per Ahlberg

Issue&Volume: Volume 573 Issue 7772

Abstract: Fossilized eyes permit inferences of the visual capacity of extinct arthropods13. However, structural and/or chemical modifications as a result of taphonomic and diagenetic processes can alter the original features, thereby necessitating comparisons with modern species. Here we report the detailed molecular composition and microanatomy of the eyes of 54-million-year-old crane-flies, which together provide a proxy for the interpretation of optical systems in some other ancient arthropods. These well-preserved visual organs comprise calcified corneal lenses that are separated by intervening spaces containing eumelanin pigment. We also show that eumelanin is present in the facet walls of living crane-flies, in which it forms the outermost ommatidial pigment shield in compound eyes incorporating a chitinous cornea. To our knowledge, this is the first record of melanic screening pigments in arthropods, and reveals a fossilization mode in insect eyes that involves a decay-resistant biochrome coupled with early diagenetic mineralization of the ommatidial lenses. The demonstrable secondary calcification of lens cuticle that was initially chitinous has implications for the proposed calcitic corneas of trilobites, which we posit are artefacts of preservation rather than a product of in vivo biomineralization47. Although trilobite eyes might have been partly mineralized for mechanical strength, a (more likely) organic composition would have enhanced function via gradient-index optics and increased control of lens shape.

DOI: 10.1038/s41586-019-1473-z

Source:https://www.nature.com/articles/s41586-019-1473-z