Scientists have discovered the world’s oldest heart in a 380 million-year-old fossil of a loose fish.
Researchers from Curtin University in Australia found the heart to be “beautifully preserved” along with a separate fossilized stomach, intestines and liver, with the organs positioned similar to the anatomy of a shark.
The hope is that this discovery can shed light on how creatures, including humans, evolved.
This muscular organ comes from a fossilized fish with jaws that swam in the waters during the Devonian period, between 419 million and 359 million years ago.
According to the scientists, the results published in the journal Scienceswe suggest that the organs come from the body of a fish of the arthropod family – an extinct group of armored fish that had an anatomy similar to that of the modern shark.
Principal researcher Professor Kate Tringstik described their find as “remarkable” because it is very rare to find well-preserved soft tissues of ancient species.
Professor Tringstik said: “As a paleontologist who has studied fossils for more than 20 years, I was truly amazed to find a beautifully preserved 3D heart of a 380 million year old ancestor.
“Evolution is often thought of as a series of small steps, but these ancient fossils suggest there was a greater leap between jawless and jawless vertebrates.
“These fish literally have their hearts in their mouths and under their gills – just like today’s sharks.”
Researchers have found fossils in the Gogo Formation in the Kimberley region of Western Australia, a coral reef that preserves unique animals and plants from the late Devonian period.
Based on the discoveries, the researchers created 3D models of jawed fish, which showed that the heart consists of two chambers, and the smaller chamber sits on top.
Professor Trinagistic said their findings offer a “unique window” into how the head and neck region begins to evolve to accommodate the jaws.
She said, “For the first time, we could see all the organs together in a primitive fish with a primitive jaw, and we were especially surprised to learn that they weren’t completely different from us.
“However, there was one fundamental difference – the liver was large and enabled the fish to stay afloat, just like sharks today.
“Some bony fish today, such as the lungfish and the birch fish, have lungs that developed from swimming bladders, but it was significant that we found no evidence of lungs in any of the extinct armored fish we examined, suggesting that they evolved independently in fish osteophytes at a later time.”
Professor John Long, of Flinders University, who was a co-author of the study, called the find “truly the stuff of a paleontologist’s dreams.”
He added, “Gogo has given us the world’s first, from the origins of the genus to the oldest vertebrate core, and is now one of the world’s most important fossil sites.
“It is time to seriously consider the site as a World Heritage Site.”
Additional Reports by PA