Scientists have discovered the oldest heart in the world in the fossil of a 380-million-year-old maxilla fish.
Researchers at Curtin University in Australia have discovered a “beautifully preserved” heart with a separate fossilized stomach, intestines and liver, with an arrangement of organs similar to the anatomy of a shark.
The hope is that the discovery could shed light on the evolution of creatures, including humans.
The muscular organ is derived from a fossilized, jawed fish that swam in Devonian waters between 419 and 359 million years ago.
According to the researchers, the findings were published in the journal Sciencesuggest that the organs come from the body of a fish in the arthroder family – an extinct group of armored fish with an anatomy similar to that of a modern shark.
The lead researcher, Professor Kate Trinajstic, described their discovery as “remarkable” because it is very rare to find such well-preserved soft tissues of ancient species.
Prof. Trinajstic said: “As a palaeontologist who has been studying fossils for over 20 years, I was really amazed to find a three-dimensional and beautifully preserved heart in an ancestor of 380 million.
“Evolution is often thought of as a series of small steps, but these ancient fossils suggest that there has been a larger jump between jawless and jawless vertebrates.
“These fish literally have a heart in their mouth and under their gills – just like today’s sharks.”
Scientists have found fossils in the Gogo Formation in the Kimberley Region of Western Australia, a reef that preserves unique late Devonian fauna and flora.
Based on these findings, scientists created 3D models of mandibular fish that showed that the heart consists of two chambers, with the smaller one at the top.
Prof. Trinajstic said their findings offer a “unique window” on how the head and neck region began to evolve to accommodate the jaws.
She said, “This is the first time we can see all the organs together in a primitive jawfish, and we were especially surprised to learn that they were not that different from us.
“But there was one critical difference – the liver was large and allowed the fish to stay buoyant like today’s sharks.
“Some of today’s bony fish, such as lungfish and birchers, have lungs that evolved from swim bladders, but it was significant that we found no evidence of lungs in any of the extinct armored fish we studied, suggesting they evolved independently in bone fish on a later date. “
Professor John Long of Flinders University, who co-authored the study, described the discovery as “a palaeontologist’s true dream.”
He added: “Gogo has given us world-wide novelty, from the beginnings of sex to the heart of the oldest vertebrate, and is now one of the most important fossils in the world.
“The time has come for the site to be seriously considered in terms of World Heritage status.”
Additional reporting by PA