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A bizarre sea beast with a circular mouth full of jagged teeth sparked a prehistoric “ arms race ” when it evolved eyes, new research has revealed.
Radiodonts stalked the oceans over 500 million years ago and are one of the first types of animals to emerge on planet Earth.
Now, a new study has revealed how their large eyes give them an advantage when hunting for food, forcing their prey to adapt or die, and fueling an evolutionary surge.
While other animals at the time also had eyes, the eyes of the radiodonts were particularly sophisticated, giving them the advantage in dimly lit areas of the ocean.
Radiodonta stalked the oceans over 500 million years ago and is one of the first types of animals to emerge on planet Earth
John Paterson of the University of New England, the study’s lead author, said it was this “arms race” that gave birth to the diversity of life we see today.
He said: ‘The radiodonts are really weird because they look like a mixture of different animal parts stuck together.
“The head has a pair of large, spiny appendages for capturing prey, a circular mouth with serrated teeth, and a large pair of eyes.
“The rest of the body looks like that of a squid, with a series of swimming flaps along both sides of the body.
He continued, “These are some of the first animals to appear in the history of the planet.
“ Because they are so well equipped for hunting, especially with their excellent vision, they would have put a lot of pressure on their prey, especially when it came to long term survival.
“Prey species therefore had to adapt and evolve in response to this pressure, otherwise they would have had to face extinction.
“This so-called ‘arms race’ was a constant evolutionary battle between predators and prey over time, with predators adapting better ‘weapons’ and prey improving their defenses.”
He added: “It is possible that this arms race is largely responsible for the diversity of life we see today.
Dr Paterson and his team came to their conclusions after examining shale fossils from Emu Bay on Kangaroo Island, South Australia
“Once animals began to eat each other over 500 million years ago, it triggered an expanding web of complex ecological interactions that undoubtedly resulted in the evolution of new species over time. .
Dr Paterson and his team came to their conclusions after examining shale fossils from Emu Bay on Kangaroo Island, South Australia.
Until recently, relatively little was known about the eyes of radiodont, but the discovery of bigger and better eye specimens paved the way for a breakthrough.
Their large eyes gave them an advantage when hunting for food, forcing their prey to adapt or die, and fueling an evolutionary push.
One eye sample contained 28,000 jaw-dropping lenses – a number only insects like the dragonfly could rival.
Dr Paterson said: “We have shown that radiodonts have some of the largest and most complex eyes in the history of animal life.
“Not only did they have sharp vision, they were also able to see at different levels of light in the ocean.
Radiodonts had some of the largest and most complex eyes in the history of animal life, giving them sharp vision as well as the ability to see at different levels of light in the ocean.
Some were over a meter long at a time when most life forms were aquatic plants and multicellular organisms
“This includes the dark depths of the twilight zone – down to 1,000 meters – where the sunlight has all but disappeared.
He added: “Radiodonts represent some of the oldest and most primitive arthropods in existence.
“Maybe without them we wouldn’t see the immense diversity of arthropods alive today, including insects, spiders, crustaceans and centipedes.
John Paterson of the University of New England, the study’s lead author, said it was this ‘arms race’ that gave rise to the diversity of life we see today. hui.
The oldest radiodont fossils date back to around 518 million years ago, and – although it is not known exactly when they died out – the creatures appear to have survived until 400 million years ago.
A varied order of predators, their size ranged from over two meters long to just a few inches.
“There are now many known species and it became quite clear that they had varied diets,” said Dr Paterson.
“ Some would have been the great white sharks of their time – that is, top predators that ate large prey.
“However, other species probably ate tiny plankton.
“Interestingly, the largest radiodonts in existence are the ones that allegedly ate these tiny organisms, which is similar to the diet of some of today’s giant whales.
“Being quite large, it is possible that some have had a considerable lifespan, perhaps on the scale of several decades, but this is speculative.
Dr Paterson and his colleagues, Gregory Edgecombe and Diego García-Bellido, published their findings in the journal Science Advances.
WHAT WAS THE “CAMBRIAN EXPLOSION”?
Scientists have long hypothesized that a large oxygen surge during the “Cambrian explosion” was the key to the development of many animal species.
The Cambrian Explosion, around 541 million years ago, was a time when a wide variety of animals burst onto the evolutionary scene.
Before about 580 million years ago, most organisms were simple, made up of single cells sometimes organized in colonies.
Over the next 70 or 80 million years, the pace of evolution accelerated and the diversity of life began to resemble that of today.
It ended with the Cambrian-Ordovician extinction event, about 488 million years ago.
A recent study has linked the historic increase in oxygen responsible for the formation of animal life on Earth to fossil fuels. Pictured: This black shale, formed 450 million years ago, contains fossils of trilobites and organic matter that helped support them in oxygen
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