Oldest Footprint Ever Discovered on Earth

Experts have found what appears to be the oldest of the footprints that ever marked the soil of the planet, in the remains of a shallow sea in Nevada. Apparently made 570 million years ago by the first animals that evolved legs, this footprint comes to push the walking advent 30 million years further in time.

 

Researchers believe animals emerged from the sea and gradually adapted to life on land, by growing lungs and legs. This particular series of parallel rows of 2-millimeter-across tracks is thought to have its origins set during the Ediacaran period that preceded the Cambrian age, when most of the animals appeared. This changes the prior belief according to which there were only microorganisms and simple multicellular life forms before the Cambrian.

As Professor Loren Babcock from Ohio State University states, “We keep talking about the possibility of more complex animals in the Ediacaran – soft corals, some arthropods, and flatworms – but the evidence has not been totally convincing. But if you find evidence, like we did, of an animal with legs – an animal walking around – then that makes the possibility much more likely.”

 

The footprints were discovered in 2000, during a rock survey in the mountainous region of Goldfield, Nevada. “This was truly an accidental discovery. We came on an outcrop that looked like it crossed the Precambrian-Cambrian boundary, so we stopped to take a look at it. We just sat down and started flipping rocks over. We were there less than an hour when I saw it,” professor Babcock explains. The nature of the animal that left these marks in the soil is still subject to dispute, but Babcock thinks (“reasonably certain – not 100%”) it may have been an centipede or millipede-like arthropod, or a legged kind of worm. This discovery was preceded by the finding of fossil tracks in Canada (dating from the mid-Cambrian, 520 years ago) and by similar ones in China (supposedly produced 540 million years ago).

 

Referring to his own finding, Babcock concludes: “I expect that there will be a lot of skepticism – there should be. But I think it will cause some excitement. And it will probably cause some people to look harder at the rocks they already have. Sometimes it's just a matter of thinking differently about the same specimen.”