Scientists in Europe found a 530 million-year-old fossil of a now extinct creature called a trilobite during a recent excavation in Estonia. However, most remarkable about the find are the remnants of the crab-like creature’s eye. The fossilized remains may represent the oldest specimen of an eye, and offer researchers a glimpse into how creatures viewed the world several hundred million years ago.
Although half a billion years old, the fossil is incredibly well preserved, and reveals not only how the ancient eye was structured, but also how it worked. In a study now published online in Proceedings of the National Academy of Sciences, the team of international scientists explains how the ancient eye fossil helps connect the dots of how vision evolved from rudimentary stages to the complex trait it is today.
“With approximately 100 ‘pixels,’ the performance of this eye dating back more than half a billion years is certainly not outstanding,” explained study co-author Brigitte Schoenemann, a zoologist at the University of Cologne, in a statement. “But it was sufficient to provide the trilobite with information on movement in its field of vision, for example approaching predators.”
To put that into perspective, the resolution of the human eye is about 576 megapixels. Schoenemann told Newsweek that the eye was discovered by chance as she and her team were attempting to investigate the shell of the trilobite, a now extinct creature that is the ancient ancestor of modern day crabs and spiders. Trilobites are the most primitive animal known to have vision, and archaeologists estimate that they lived between 521-25 million years ago.
Unlike modern-day eyes, this prehistoric eye lacks a lens. Instead, it was covered by a surface called a “palpebral lobe,” the report explained. In humans, the lens works to help focus light as it passes through the eye, Live Science reported. After light passes through the lens it then strikes the retina, a layer of sensitive cells that convert visual information into electrical signals and send them to the brain.
Without a lens, this ancient eye likely could not see very clearly. Despite its primitive nature, the eye was still able to discern light in its surroundings. This ability likely helped it move around and navigate more easily.
Study co-author Euan Clarkson, of the University of Edinburgh’s school of GeoSciences, told The Independent that the structure of this ancient eye and its basic similarity to modern animal eyes shows just how little eyes have evolved over the past half a billion years.
The fossils are currently being stored at the Institute of Geology, at Tallinn University of Technology, Estonia, and not open for viewing at this time.