Center for Marine Environment Studies, Kumamoto University, 6061 Matsushima-cho, Kami-amakusa, Kumamoto 861-6102, Japan.
Department of Life Sciences, Natural History Museum, London SW7 5BD, UK.
Nat Commun. 2014 Dec 23;5:5920. doi: 10.1038/ncomms6920.
Vision, which consists of an optical system, receptors and image-processing capacity, has existed for at least 520 Myr. Except for the optical system, as in the calcified lenses of trilobite and ostracod arthropods, other parts of the visual system are not usually preserved in the fossil record, because the soft tissue of the eye and the brain decay rapidly after death, such as within 64 days and 11 days, respectively. The Upper Carboniferous Hamilton Formation (300 Myr) in Kansas, USA, yields exceptionally well-preserved animal fossils in an estuarine depositional setting. Here we show that the original colour, shape and putative presence of eumelanin have been preserved in the acanthodii fish Acanthodes bridgei. We also report on the tissues of its eye, which provides the first record of mineralized rods and cones in a fossil and indicates that this 300 Myr-old fish likely possessed colour vision.
视觉系统由光学系统、感受器和图像处理能力组成，至少已经存在了 5.2 亿年。除了光学系统，如三叶虫和介形类节肢动物的钙化晶状体，视觉系统的其他部分通常不会在化石记录中保存下来，因为眼睛和大脑的软组织在死亡后会迅速腐烂，分别在 64 天和 11 天内。美国堪萨斯州上石炭统汉密尔顿组（3 亿年前）在河口沉积环境中产生了保存异常完好的动物化石。在这里，我们展示了棘鱼 Acanthodes bridgei 的原始颜色、形状和可能存在的真黑色素的保存情况。我们还报告了它眼睛的组织，这是化石中首次记录到矿化的视杆和视锥，表明这条 3 亿年前的鱼可能具有色觉。
