Scientists in Australia have found perfectly preserved fossilized hearts and other internal organs of ancient “armored” fish. This discovery allows us to understand the evolution of the body of vertebrates, including humans, Reuters reports.

Australian researchers believe they have discovered the oldest heart ever found, 380 million years old, informs DPA/PA Media, writes Agerpres.

The muscular organ comes from a fossilized jawed fish that lived in the Devonian period, between 419 and 359 million years ago.

Along with the “perfectly preserved” heart, the researchers also discovered a stomach, intestines and liver, all fossilized.

According to scientists, the results, published in the journal Science, indicate that the organs come from the body of a fish from the Arthrodir family, an extinct group of “armored” fish with an anatomy similar to a modern shark.

It is hoped that this discovery will bring new information about the evolution of living things, including humans.

The opening is “great”

Lead researcher Kate Trynastick of Curtin University in Australia called the discovery “remarkable” because it is very rare to find soft tissues of ancient species in such a good state of preservation.

“As a paleontologist who has been studying fossils for over 20 years, I was truly amazed to find a three-dimensional and beautifully preserved heart from an ancestor from 380 million years ago,” said Trinaistik.

“Evolution is often thought of as a series of small steps, but these ancient fossils provide evidence of a larger leap from jawless to jawed vertebrates. These fish literally have their hearts in their mouths and under their gills – just like modern sharks,” she said.

What the heart of a fish that lived almost 400 million years ago looks like

Based on the discovery, the researchers created 3D models of the jawed fish, which showed that the heart consists of two chambers, the smaller of which is located at the top.

Trinstadic said the findings provide a “unique window” into how the head and neck region began to evolve to make way for the jaws.

“For the first time we can see all the organs together in a primitive jawed fish, and we were particularly surprised to learn that they are not very different from us,” she said.

“However, there was a significant difference – the liver was large and allowed the fish to swim, as in the case of modern sharks,” Trinaistach said.

“Some of today’s bony fishes, such as dipnoi and armadillos, have lungs that evolved from swim bladders, but importantly, we have found no evidence of lungs in any of the extinct armadillos that I have studied, suggesting that they evolved independently into bony fish later,” the researcher clarified.

The fossils were discovered in the Gogo Formation in the Kimberley region of Western Australia, a reef that preserves unique Late Devonian fauna and flora.