They have been discovered in Poland

Jan 7, 2010 08:17 GMT  ·  By
The tetrapods that left tracks at the Poland quarry were probably two-meter-long, crocodile-looking beasts
   The tetrapods that left tracks at the Poland quarry were probably two-meter-long, crocodile-looking beasts

Evolutionary biologists say that, as the early life of the Earth evolved, the oceans were the main social scene around. This was until some species decided that the competition was too steep, and wanted to try something different. So they did, and some of them started living in shallow waters near shorelines, making occasional and short incursions on land. They were still tied to the waters, however, and could not survive on the ground for long. Eventually, over millions of years, they adapted to their new climate, and began to walk the land, leaving prints as they did. The oldest such fossilized records of the earliest walkers on the planet have been recently found in Poland, the BBC News reports.

According to the investigators who have had a chance to look at the fossils and analyze the data, the tracks appear to have been made more than 397 million years ago. They were discovered in a disused quarry in southeastern Poland, and belong to a yet-unknown creature. In addition to its own historic value, the new fossils also shed doubt on established anthropological knowledge, in the sense that land-walking animals apparently appeared millions of years before scientists estimated they did. The tracks are so faithful, that even the impressions left by the toes of the creature were preserved in hard rock.

“This place has yielded what I consider to be some of the most exciting fossils I've ever encountered in my career as a paleontologist. [They are] fossil of footprints that give us the earliest record of how our very distant ancestors moved out of the water and moved on to the land and took their first steps,” expert Per Ahlberg says. He is a member of the research team that studied the fossils, and is based at the Uppsala University, in Sweden. The group that made the discovery says that the Zachelmie Quarry, which is located in the Holy Cross Mountains, is a treasure trove of similar tracks, belonging to different animals, spread out over the planet's ancient history.

“The discovery of undoubted track ways from the earliest period of the Eifelian – that is 379 million years ago – pushes back the divergence between fishes and the four-legged vertebrates by about 18 million years, if not probably more. I suspect that now we can push the divergence back to the Emsian stage, maybe 400 million years ago. That's surprising, but this is what the fossil evidence tells us,” independent researcher Dr. Philippe Janvier, from the National Museum of Natural History, in Paris, France, adds. He reveals that the new prints hint at the fact that the early tetrapods – four-legged animals – might have lived in coral lagoons, and not in swamps and marshes as first thought.