The fossil of an extinct sea creature contains what could be the oldest eye ever discovered, a study has found. The researchers from University of Edinburgh in the U.K. said that the remains include an early form of the eye seen in many of today's animals, including crabs, bees and dragonflies.
The hard-shelled species — called a trilobite, is the ancestor of spiders and crabs and lived in the coastal waters during the Palaeozoic era, between 541-251 million years ago, researchers said.
They found that the ancient creature had a primitive form of compound eye — an optical organ that consists of arrays of tiny visual cells, called ommatidia, similar to those of present-day bees. Its eye consists of about 100 ommatidia, which are situated relatively far apart compared to contemporary compound eyes, they said.
The findings, published in the journal PNAS , suggest that compound eyes have barely changed over 500 million years. The right eye of the fossil — which was unearthed in Estonia — was partly worn away, giving researchers a clear view inside the organ. The species had poor vision compared to many animals today, but it could identify predators and obstacles in its path, researchers said.
The team also revealed that only a few million years later, improved compound eyes with higher resolution developed in another trilobite species from the present-day Baltic region. "This exceptional fossil shows us how early animals saw the world around them hundreds of millions of years ago," said Professor Euan Clarkson, from the University of Edinburgh.
