World-first research at Flinders University shows how fish first learnt how to breathe air and evolved into land animals A perfectly preserved, 380-million-year-old fish fossil discovered from the Kimberley, that shows huge holes on top of the head - the spiracles through which it also breathed air. This fish is on a direct line of evolution leading to land animals (early amphibians) and eventually through reptiles and mammals to humans. The head of the African reed fish, the polypterus, with a probe showing the spiracle on top of the head through which it breathes. A FLINDERS University palaeontologist has found world-first evidence that reveals how the ancient fish that would later evolve into land animals began breathing air. The research, published in the journal Nature Communications today, shows a native African fish called the Polypterus breathes air through large canals on top of its head. Professor John Long said the major evolutionary breakthrough solved the "hundred-year-old mystery that was debated about how these things (fish) breathe." "Some early 19th-century scientists had these wacky ideas that fish just jumped on to the land and started gasping for breath and developing limbs," he said. Until now, we've only had theories about the origins of breathing in the evolution of fish to land animals. After studying the live fish in tanks, Professor Long, who conducted the research along with a team of scientists in the United States, found they were actually breathing through the holes on top of their head, not from their mouths like most other fish species. "People have theorised in the past (but) this is the first evidence showing how fishes first began to breathe air," he said. Then they were on the lineage that would one day evolve to land animals and the rest of the evolution that led to humans. Once the creatures left the water and were established on land, they then started breathing through their noses and mouths like humans do today. "We use this information because it informs us about where we come from as a species," Professor Long said. He said the discovery was a long time coming and the first step in the evolutionary transition of ancient fishes to four-legged animals. "Three-hundred-and-eighty million years ago we've got these strange fossil fishes that had large holes on top of their heads (but) we didn't know what they were for," he said. Our research shows that the transformation actually started happening within the fish themselves while they were in the water. Professor Long undertook the research along with a team based at the Scripps Research Institute in Los Angeles. "It is curiosity-driven research that informs us about our place in the universe," he said.