London, Dec 8 (PTI) A 530-million-year-old fossil of anextinct sea creature contains what could be the oldest eyeever discovered, a study has found.
The remains include an early form of the eye seen in manyof today's animals, including crabs, bees and dragonflies,researchers said.
Scientists, including those from the University ofEdinburgh in the UK, made the finding while examining thewell-preserved fossil of a hard-shelled species - called atrilobite.
These ancestors of spiders and crabs lived in coastalwaters during the Palaeozoic era, between 541-251 millionyears ago, researchers said.
They found the ancient creature had a primitive form ofcompound eye - an optical organ that consists of arrays oftiny visual cells, called ommatidia, similar to those ofpresent-day bees.
The findings, published in the journal PNAS, suggest thatcompound eyes have changed little over 500 million years.
The right eye of the fossil - which was unearthed inEstonia - was partly worn away, giving researchers a clearview inside the organ.
This revealed details of the eye's structure andfunction, and how it differs from modern compound eyes.
The species had poor vision compared with many animalstoday, but it could identify predators and obstacles in itspath, researchers said.
Its eye consists of about 100 ommatidia, which aresituated relatively far apart compared to contemporarycompounds eyes, they said.
Unlike modern compound eyes, the fossil's eye does nothave a lens. This is likely because the primitive species -called Schmidtiellus reetae - lacked parts of the shellneeded for lens formation.
The team also revealed that only a few million yearslater, improved compound eyes with higher resolutiondeveloped in another trilobite species from the present-dayBaltic region.
"This exceptional fossil shows us how early animals sawthe world around them hundreds of millions of years ago,"said Professor Euan Clarkson, from the University ofEdinburgh.
"Remarkably, it also reveals that the structure andfunction of compound eyes has barely changed in half abillion years," said Clarkson.
"This may be the earliest example of an eye that it ispossible to find," said Professor Brigitte Schoenemann, ofthe University of Cologne in Germany.
"Older specimens in sediment layers below this fossilcontain only traces of the original animals, which were toosoft to be fossilised and have disintegrated over time," saidSchoenemann. PTI SARSAR.
This is unedited, unformatted feed from the Press Trust of India wire.