World’s oldest heart found in prehistoric fish

World’s oldest heart found in prehistoric fish

Gogo fish 2 game

Artist’s impression of Gogo fish

Researchers have found a 380 million year old heart preserved inside a prehistoric fish fossil.

They say that the specimen captures an important moment in the evolution of the blood-pumping organ found in all vertebrate animals, including humans.

The heart belonged to a fish called the Gogo, which is now extinct.

The “jaw-dropping” discovery, published in the journal Science, was made in Western Australia.

The lead scientist, Professor Kate Trinajstic from Curtin University in Perth told BBC News about the moment she and her colleagues realized they had made the biggest discovery of their lives.

“We were crowded around the computer and we recognized that we had a heart and we couldn’t believe it! It was really exciting,” she said.

Fossil fish

The fish are perfectly preserved in boulders found in the Kimberley region of Western Australia

Fossils are usually made of bones rather than soft tissue – but at this Kimberley site, known as the Gogo rock formation – many of the fish’s internal organs have been preserved by minerals, including the liver, stomach , the intestine and the heart.

“This is a crucial moment in our own evolution,” said Professor Trinajstic.

“It shows the body plan that we changed very early, and we see this for the first time in these fossils.”

Her colleague, Professor John Long from Flinders University in Adelaide, described the discovery as a “quick, fake discovery”.

“We didn’t know anything about the soft organs of animals this old, until now,” he said.

A comparison between Gogo fish and the human heart

The heart of the Gogo fish had two chambers, one above the other, which grew into the human heart

The Gogo fish is the first of a class of prehistoric fish known as placoderms. These were the first fish to have jaws and teeth. Before them, fish were no bigger than 30cm, but placoderms could grow up to 29.5 feet (9m) long.

Placoderms were the planet’s main life form for 60 million years, which was more than 100 million years before the first dinosaurs walked the Earth.

Scans of the Gogo fish fossil revealed that its heart was more complex than expected for these primitive fish. There were two chambers, one on top of the other, similar to the structure of the human heart.

The researchers suggest that this made the animal’s heart more efficient and was the critical step that changed it from a slow-moving fish to a fast-moving predator.

Scan with heart

The researchers scanned inside the boulders to discover a liver, stomach, intestines and heart, shown in red

“This was the way they could up the ante and be a voracious predator,” said Professor Long.

The other important observation was that the heart was much larger in the front of the body than those of more primitive fish.

This position is thought to have had something to do with the development of the Gogo fish’s neck and made room for the development of the lung further down the evolutionary line.

Gogo fish skeleton

Gogo fish head fossils with large eye sockets

Dr Zerina Johanson of the Natural History Museum, London, who is a world leader in placoderms, and who is independent of Professor Trinajstic’s team, described the research as “a very important discovery” which helps to explain why which is the human body as it is. today.

“Many of the things you see are still in our own bodies; jaws and teeth, for example. We have the first appearance of the front and back fins, which eventually evolved into our arms and feet.

“There are many things going on in these placoderms that we see evolving for ourselves today such as the neck, the shape and arrangement of the heart and its position in the body.”

The discovery completes an important step in the evolution of life on Earth, according to Dr Martin Brazeau, a placoderm expert at Imperial College London, who is also independent of the Australian research team.

“It’s really exciting to see this result,” he told BBC News.

“The fish that my colleagues and I are studying are part of our evolution. This is part of the evolution of humans and other animals that live on land and the fish that live in the sea today.”

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