A fossil found in an ancient organism that was one of the earliest vertebrate species on our planet has been discovered to contain an amazing surprise.
A 380 million year-old fossilized armored fish was found by paleontologists. They discovered a mineralized, three-dimensionally preserved heart.
This is an amazing find. These soft tissues are very rare in fossil records, and tend to decay before fossilization can occur. Three-dimensional soft tissue is even rarer.
It gets even better. Researchers were able to examine the fossil’s anatomy in 3D using scans. The fossil’s remarkable preservation allows for the identification of details such as an atrium and ventricle, as well an outflow tract.
The heart of an ancient fish was an S-shaped organ consisting of two chambers. The smaller chamber was on top of its larger counterpart. This organ was far more advanced than paleontologists believed it would be and could give vital information about evolution of the neck and head region and how they changed to accommodate jaws. Say it.
“As an expert paleontologist and a researcher in fossils, I was truly surprised to find a beautifully preserved 3D heart in a 380m-year-old ancestor.” says palaeontologist Kate TrinajsticCurtin University, Australia
Although evolution is often regarded as a series or small steps, these ancient fossils show that there was a much larger leap between jawless and jawed vertebrates. These fish literally have their hearts in their mouths and under their gills – just like sharks today.”
The fossil is from the Gogo Formation, located in the northernmost corner Western Australia. This area was home to the fossils of 419.2 million and 358.9million years ago during Devonian. A vast reef that is alive with life. Now, it’s a fossil bed classified as a Lagerstätte – so exceptional that sometimes even soft tissues have been preserved.
The fossil was left behind by an animal that belonged to an extinct species of armored fishing fishes, called arthrodires. These animals thrived For approximately 50 million years The Devonian, before it was wiped out by a major global event at the end of that period.
This specimen is made up of a chunk of limestone rock with some strangely biographical features. Once, it would have been difficult to analyse without destroying the stone.
It’s no longer necessary to crack open fossils in order to discover what’s inside.
“What is really remarkable about Gogo fishes are their soft tissues that they preserve in three dimensions.” says paleontologist Per AhlbergUppsala University, Sweden
“Most cases for soft-tissue preservation are found within flattened fossils. This is where the soft anatomy can barely be seen. It is also very lucky that we have modern scanning techniques that allow us to study fragile soft tissues without having to destroy them. This project would have been impossible just a few decades ago.
The team worked with scientists from the Australian Nuclear Science and Technology Organisation and European Synchrotron Radiation Facility to map the various mineral densities within the fossil. They used synchrotron Xray imaging and neutron beams to do this. These densities not only showed the Conserved bones of the arthrodire, but other less robust features – a spectacular heart, as well as a stomach, intestine and liver.
The presence of other organs allowed the team the opportunity to study the anatomy of the fish.
“For the very first time, we could see all the organs together within a primitive jawed Fish, and it was especially surprising to find that they were not as different from us.” Trinajstic says.
“However, there was one critical difference – the liver was large and enabled the fish to remain buoyant, just like sharks today. Today’s bony fish, such as lungfish or birchers, have lungs that evolved form swim bladders. However it is significant that we did not find evidence of lungs in any extinct armored fishes that we examined. This suggests that they may have evolved later in their own time.
The Gogo Formation contained fossils that were previously excavated. This allowed paleontologists the opportunity to reconstruct and understand the Gogo Formation. MusculatureGogo arthrodires. The formation also revealed arthrodire embryos.
This new specimen suggests there may be more treasures in Australia’s outback.
“These soft organs found in ancient fishes are truly the stuff that palaeontologists have been dreaming about. These fossils are, without doubt, the best preserved fossils anywhere in the world for their age.” says paleontologist John LongFlinders University, Australia
They are a testament to the importance of the Gogo fossils in understanding the major steps in our distant evolutionary history. Gogo is a world-first fossil site, containing everything from the origins and evolution of sex to the oldest known vertebrate heart. It is one of the most important in the world. It’s high time that this site is given international heritage status.
The research was published in Science.
