Paleontologists Uncover Oldest Ever Completely Intact Fossilized Heart

by Amy Myers

This week, paleontologists have made an incredible discovery of a fossilized heart that links us to our oldest jawed relatives, and the estimated age of the fossil is enough to have our jaws on the ground.

The fossilized heart itself is a pretty amazing discovery, considering the fact that soft tissue just doesn’t preserve as well as hard tissue like bones. Sure, we’ve seen plenty of skulls of prehistoric fish, reptiles and birds. But rarely do we have the chance to study the vital organs of these ancient creatures. That’s why this 380-million-year-old, three-dimensional heart is such a vital discovery for researchers.

According to Reuters, the fossil belongs to an underwater creature called a placoderm, a prehistoric fish that is now extinct.  Kate Trinajstic, lead author and paleontologist at Curtin University in Australia, explained that these are our earliest relatives with jaws. These placoderms existed roughly 416 million to 359 million years ago.

Understandably, researchers are celebrating their fish fossil.

It’s “a mind-boggling, jaw-dropping discovery,” John Long, a paleontologist at Flinders University in Australia and co-author of the paper, told BBC News. “We have never known anything about the soft organs of animals this old, until now.” 

See the fossilized organ here.

380-Million-Year-Old Fossilized Heart Resembles Features of Present-Day Sharks

While these fish are ancestors of humans, they also lend similarities to fellow gilled animals. Trinajstic shared that there was one distinct feature of the heart that was strikingly familiar.

“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,” Trinajstic shared. “However, there was one critical difference—the liver was large and enabled the fish to remain buoyant, just like sharks today.”

For paleontologists, the discovery of the fossilized heart helps fill in some of the building blocks of our evolution.

“Here we are, right at the beginning of the jawed vertebrates, and that step’s already there,” Trinajstic said.

Zerina Johanson of London’s Natural History Museum agreed, “There are many things going on in these placoderms that we see evolving to ourselves today such as the neck, the shape and arrangement of the heart and its position in the body.”

Trinajstic, Johanson and Long are just a couple of the many scientists that are enraptured by the organ. José Xavier Neto is one of the paleontologists that helped discover the first-ever fossilized vertebrate heart six years ago.

“It is very exciting indeed,” Neto told Scientific American. “Only six years after our initial discovery, it’s great to see that other groups are also being able to report on fossil hearts. The field is really new, and we really need high-quality data.”