days ago, Australian researchers found a 380 million-year-old heart on an ancient jawed fish fossil. Screenshot
Australian researchers found a 380 million-year-old heart in an ancient jaw fish fossil, as well as individual stomach, intestine and liver fossils. This is the oldest heart ever discovered. The study shows that the organ locations in the body of this turtle, which flourished and now extinct during the Devonian period 419.2 million years ago to 358.9 million years ago, have similar anatomical structures to modern sharks, which provides important clues for studying human own evolution. The results of the related research of
were published in Science on September 15.
These fossils were found in the Gogo group in the Kimberley region of western Australia, which was originally a huge coral reef. The discovery is remarkable, said Kate Trinajstic, the corresponding author of the study and principal investigator at Curtin University’s School of Molecular and Life Sciences and the Western Australia Museum. Soft tissues in ancient species are rarely preserved and are even rarer in three-dimensional preservation, so the discovery is remarkable.
"Evolution is often considered a series of small steps, but these ancient fossils show a bigger leap between jawless and jawed vertebrates. The hearts of these fish are in their mouths and under their gills, just like today's sharks," Trinajstic said.
This study demonstrates for the first time a 3D model of a complex S-shaped heart. The model consists of two chambers, with smaller chambers located on top. These characteristics are advanced in early vertebrates, providing a unique window into how the head and neck areas begin to change to adapt to the jaw, which is also a critical stage in the evolution of the human body.
However, Trinajstic pointed out that a key difference is that the fish has a large liver and can keep the fish buoyant, just like today's sharks. But the lungs of some bone fish, such as lung fish and birch fish, evolved from the fish bladder. "Importantly, we have no evidence of lungs found in any extinct turtles, suggesting that they later evolved independently in bone fish."
With the help of the Australian Nuclear Science and Technology Organization and the French European Synchrotron Radiation Facility, the researchers used neutron beams and synchrotron X-rays to scan fossil specimens still embedded in limestone condensates and constructed a three-dimensional image of the soft tissue inside the specimen based on different densities of minerals deposited by bacteria and surrounding rock matrix.
In addition to the muscles and embryos found previously, this new discovery of mineralized organs has made the Gogo group turtle the most fully understood animal of all jaw stem vertebrates and elucidates its evolutionary transition to existing jaw stem vertebrates (mammals including humans). "The soft organs found in these ancient fish are indeed something paleontologists dream of, and there is no doubt that these fossils are the best preserved fossils in the world in this era. They show the great value of Gogo Group fossils in understanding the long evolution of human beings. The Gogo Group is one of the most important fossil sites in the world, from sexual origins to the oldest vertebrate hearts, creating many world firsts for us." Another co-author of
, Per, professor at Uppsala University in Sweden, said. "What really special about Gogo's fossil fish is that their soft tissue is preserved in three-dimensional space. Most examples of soft tissue preservation are found in flat fossils, where the soft tissue anatomy is just a point on the rock. We are very lucky because modern scanning technology allows us to study these fragile soft tissues without destroying them, which was impossible decades ago."
(Source: The Paper)
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