World’s oldest heart preserved in 380-million-year-old armored fish
Ars Technica » Scientific Method 2022-09-21
Researchers have discovered a 380-million-year-old heart—the oldest ever found—alongside a separate fossilized stomach, intestine, and liver in an ancient jawed fish, shedding new light on the evolution of our own bodies. Credit: Alice Clement/Curtin University
A team of Australian scientists has discovered the world's oldest heart, part of the fossilized remains of an armored fish that died some 380 million years ago. The fish also had a fossilized stomach, liver, and intestine. All the organs were arranged much like similar organs in modern shark anatomy, according to a recent paper published in the journal Science.
As we've reported previously, most fossils are bone, shells, teeth, and other forms of "hard" tissue, but occasionally fossils are discovered that preserve soft tissues like skin, muscles, organs—or even the occasional eyeball. This can tell scientists much about aspects of the biology, ecology, and evolution of such ancient organisms that skeletons alone can't convey.
For instance, earlier this year, researchers created a highly detailed 3D model of a 365-million-year-old ammonite fossil from the Jurassic period by combining advanced imaging techniques, revealing internal muscles that had never been previously observed. Among other findings, the researchers observed paired muscles extending from the ammonite's body, which they surmise the animal used to retract itself further into its shell to avoid predators.