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The humble trilobite, the helmet-headed creature that swam in the sea hundreds of millions of years ago, hid an unusual secret – an “excessive eye” unprecedented in the animal kingdom.
Looking at x-ray images, the researchers found that specific species of trilobites – extinct arthropods related to crabs – have their own neural network that processes and transmits hundreds of lenses and signals and many optic nerves. September 30 in the magazine Scientific reports.
To belong to: Why did the trilobites go extinct?
Today’s arthropods, such as dragonflies and mantis shrimp, are known for their powerful compound eyes, which consist of a myriad of eye features called ommatidia, each with its own lens like a disco ball.
But, according to new findings, the family’s trilobites The Vacops had much larger and more complex eyes than their modern arthropod cousins. Each of his eyes (one on the left and one on the right) had hundreds of lenses. These primary lenses, about a millimeter long, were thousands of times the size of conventional arthropods. Beneath them, like a car’s headlight bulbs, are six (or more) structures that resemble a typical compound eye. “So each large bacopedic eye is a high compound eye with 200 compound eyes,” Brigitte Schoenemann, archaeologist at the University of Cologne in Germany, said in an email to LiveScience.
Trilobites are organisms that lived from the early Cambrian Period (521 million years ago) to the late Permian Period (252 million years ago) in marine sites. Some can be predators of aquatic worms, although most are scavengers or plankton eaters. Limestone remains from the Cambrian period are commonly found. But despite their ubiquity in the fossil record, scientists still have questions about their physiology and evolutionary history.
To answer these few questions, the researchers examined dozens of archival photos using image enhancement techniques, interspersed with the latest findings. In the process, they also settled a long-standing scientific debate: They confirmed that a mysterious chain of “fibers” seen in x-ray images 40 years ago were in fact optic nerves connected to the eyes of trilobites. .
“It is always difficult to determine the function of ancient and extinct organisms,” said Nigel Hughes, a trilobite expert at Riverside University in California. In fact, Hughes noted, some particular characteristics of the organism are beyond explanation – for example, there is still debate about the function of the rhino’s long horn-shaped teeth. Smithsonian Institution.
However, the eyes are a little easier to penetrate than the teeth or horns, said Hughes, because visual systems have only one function: vision. “We know it’s a skeletal eye,” he said, so it makes sense that the connecting fibers are nerves. “I think this was discussed very firmly on paper.” Why trilobites might require so much visual force remains a mystery.
The x-ray images themselves were taken by Wilhelm Stormer, a professional radiologist and amateur paleontologist from Siemens. In the 1970s, Stormer installed an X-ray probe on his Volkswagen bus and developed a new method of studying fossils: X-ray paleontology, which made it possible to visualize the hard rock of the site and take its complex fossil images. daytime
While exploring Hansrock List, a fossil quarry far from his home in Munich, Germany, Stormer discovers a world of devastating creatures embedded in rock. To a large extent, these specimens – including the three-lobed rod – are so well preserved that their soft tissues are visible. Stormer and his collaborator, John Bergstrom, described the trilobites as “fiber” fossils attached to their common eyes, which they described in their June 1973 issue. Archeology journal.
To belong to: In pictures: a Cambrian creature feeding on filter
But when Stormer drew the attention of other paleontologists to these findings, “his colleagues in the scientific world ridiculed him,” Scueman said. The wisdom back then was that soft tissues, like nerves, weren’t just fossils. Scheunemann argues that Stormer Gill fibers must be confused with optic nerve tissue, as his critics have argued. However, the radiologist was adamant in his beliefs.
“Stormer believed his theory until his death and filled it with bitterness in 1986,” Schoenemann said. After nearly half a century, Scuyman and his team finally felt their work had been proven successful.
Unfortunately, like Wilhelm Stürmer, we no longer have any trilobite phagocytes – they finally went extinct 358 million years ago. devonian periodWith 75% of life on Earth, said Scheunemann. “But certainly not because of their very developed and cuddly eyes.”
First published in Live Science.
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