“For the first time, we can see all the organs together in a primitive jawed fish, and we were especially surprised to learn that they were not so different from us,” Professor Kate Trinajstic said. Source: Curtin University.
A 380-million-year-old fish heart discovered in Western Australia is believed to be the oldest heart ever found.
The heart was found in exceptional condition along with a fossilised stomach intestine and liver.
Scientists believe it can give them more insight into jawed vertebrates, including humans, and their evolution.
Curtin University-led research is studying the fossil which was collected from the Gogo formation that was once a large reef at the Kimberley region in Western Australia.
The location is known for a rich fossil record preserving reef life, including remnants of tissue as delicate as nerves and embryos with umbilical cords.
The heart belonged to an extinct class of armoured, jawed fish called arthrodires that lived during the Devonian period hundreds of millions of years ago.
It is 250 million years older than the jawed fish heart that previously held the oldest title.
“As a palaeontologist who has studied fossils for more than 20 years, I was truly amazed to find a three-dimensional and beautifully preserved heart in a 380-million-year-old ancestor,” said Professor Kate Trinajstic of Curtin University.
Researchers were surprised from seeing the anatomical resemblance between the ancient fish and modern sharks.
“Evolution is often thought of as a series of small steps, but these ancient fossils suggest there was a larger leap between jawless and jawed vertebrates.
“These fish literally have their hearts in their mouths and under their gills — just like sharks today.”
In their study published in the journal Science, the scientists explained how the complex features of the arthrodire’s S-shaped heart comprising of two chambers, were quite advanced in such early vertebrates.
These features offer a window into how the head and neck region evolved for jaws, a key stage in our own evolution.
Scientists were able to examine the heart in relation to the remains of the fish’s stomach, liver and intestine, which is a rare occurrence.
“Most cases of soft-tissue preservation are found in flattened fossils, where the soft anatomy is little more than a stain on the rock,” said Per Ahlberg, professor at Sweden’s Uppsala University.
“We are also very fortunate in that modern scanning techniques allow us to study these fragile soft tissues without destroying them. A couple of decades ago, the project would have been impossible.”
