Researchers said Thursday a well-preserved 429 million-year-old eye from a sea creature that was extinct before dinosaurs had a vision comparable to today’s bees and dragonflies.
The fossilized trident, the formidable arthropod with its fragmented body and sturdy exoskeleton, is found all over the world.
The creatures crawled across the ancient seabed in the Paleozoic Era, which arrived and ended some 252 million years ago during the “great dying” period, an extinction event that wiped out 95% of life on Earth.
The specimen was detailed in the magazine Scientific reports only one to two millimeters tall and has two protruding semi-oval eyes on the back of the head, one of which was fractured.
Using digital microscopes, researchers from Germany and the UK have found that the internal structure is similar to that of modern insects and crustaceans, which see through a small lens hive, each with a separate visual unit that captures a small array of light.
Co-author Brigitte Schoenemann, of the Department of Zoology at the University of Cologne, said: “In this small trilobite, the compound eye resembles today’s bee, dragonfly and many modern day-active crustaceans ( activities during the day).
“So the system seems to be very effective, very old,” she told AFP.
While it was previously known that these double-eyed trebles, older specimens had “slit-in” eyes, “horizon-only” eyes, and had no lenses on the visual unit.
“In this trilobite, the field of vision widens, the eyes also look up partly.
The human eye has a single lens and tens of millions of light-sensitive cells, creating an advanced imaging level.
Schoenemann says that in the compound eye, each visual unit works separately to provide a single pixel, “just like in computer graphics”.
The trilobite studied has only 200 of these, giving it mosaic vision that can help it see “obstacles, shelters” and most importantly predators like ancient cephalopods – nests distant fairy of nautilus and octopus.
By comparison, she says honey bees have several thousand “pixels” of these, while dragonflies have 30,000 per eye.
“So the resolution is different, but the principle is not functional.”
Since each lens in the trilobite’s eye is small (35 micrometres in diameter), the researchers concluded that it lives in shallow, light-flooded waters, like some species of coastal crabs today.
Trilobite mentioned was first discovered in 1846 near Lodenice, Czech Republic.
Schoenemann said the specimen was not unusual, suggesting that further study of the existing fossils could uncover delicate structures that until recently were thought to have disappeared. time.
“I simply like this three-spiked fish with its big head and big eyes. But when I looked through the microscope what I saw was breathtaking,” she said.
“Not long ago, it was thought that in fossils only teeth, bones and those things could be preserved, but there was never the cellular structure. This has obviously changed.”
Three-tailed fish first began to appear in the so-called Cambrian Explosion – an increase in biodiversity more than half a billion years ago – and they inhabited the oceans for about 250 million years.
Dinosaurs appeared later and existed for about 180 million years.
Eye transplant is an ongoing feature of evolution
An insight into a 429 million year old compound eye, Scientific reports (Year 2020). DOI: 10.1038 / s41598-020-69219-0, www.nature.com/articles/s41598-020-69219-0
© 2020 AFP
Quote: Fossilized 429 million-year-old eyes that reflect the vision of modern insects (2020, August 13) retrieved August 14, 2020 from https://phys.org/news/2020-08- million-year-old-eye-view-trilobite -life.html
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