Scientists say it belonged to a fish known as the Gogo, which is now extinct. Kate Trinajstic from Curtin University in Perth who helped unearth this discovery, says it's one of the biggest discoveries of her and her colleagues life. The heart being preserved was made possible because minerals preserved many of the fish's internal organs, including the liver, stomach, intestine and heart. Trinjastic went on to say that this discovery was a "crucial moment in our own evolution"
Check out the rendering of the Gogo fish might have looked like nearly 400 million years ago