An "exceptional" 530-million-year-old fossil contains what could be the oldest eye ever discovered, according to scientists.
The remains of the extinct marine creature include a primitive form of the eye that is seen in many of today's animals, including crabs, bees and dragonflies.
Scientists made the finding while observing the well-preserved trilobite fossil.
These ancestors of spiders and crabs lived in the seas during the Paleozoic era, between 541-251 million years ago.
They found that the ancient creature had a primitive form of compound eye, an optical organ consisting of arrays of tiny visual cells, called ommatidia, similar to those of current bees.
The team, which included a researcher from the University of Edinburgh, said its findings suggested that compound eyes had changed little more than 500 million years ago.
Professor Euan Clarkson, from the geosciences school at the University of Edinburgh, said: "This exceptional fossil shows us how primitive animals saw the world around them hundreds of millions of years ago.
" Surprisingly, It also reveals that the structure and function of compound eyes has barely changed in half a billion years. "
The right eye of the fossil, which was unearthed in Estonia, was partly worn, giving researchers a clear view inside the organ.
This revealed details of the structure and function of the eye, and how it differs from modern composite eyes
The species had poor vision compared to many animals today but could identify predators and obstacles in their path, researchers believe.
His eye consists of approximately 100 ommatidia, found relatively separate compared to current compound eyes, the team has found.
Unlike modern compound eyes, the fossil eye does not have a lens.
T The team believes that this is probable because the primitive species, called Schmidtiellus reetae, lacked the shell parts necessary for lens formation.
Prof. Brigitte Schoenemann, of the Universid Ad of Cologne, who also participated in the study, said: "This may be the first example of an eye that is possible to find.
"Older specimens in sediment layers beneath this fossil contain only traces of the original animals, which were too soft to be fossilized and have disintegrated over time." 19659007] The team also revealed that only a few million years later, enhanced compound eyes with a higher resolution developed in another trilobite species of the current Baltic region.
The study was published in the journal Proceedings of the National Academy of Sciences.
It was carried out in collaboration with the University of Cologne and the Tallinn Technological University in Estonia.