570 million years old

Oldest ‘Footprints’ on Earth Found
LiveScience

Oct. 5) – The oldest-known tracks of a creature apparently using legs have been discovered in rock dated to 570 million years ago in what was once a shallow sea in Nevada.

Scientists think land beasts evolved from ancient creatures that left the sea and evolved lungs and legs. If the new finding is real — the discoverer says will fuel skepticism — it pushes the advent of walking back 30 million years earlier than any previous solid finding.

The aquatic creature left its “footprints” as two parallel rows of small dots, each about 2 millimeters in diameter. Scientists said today that the animal must have stepped lightly onto the soft marine sediment, because its legs only pressed shallow pinpoints into that long-ago sea bed.

The tracks were made during what is called the Ediacaran period, which preceded the Cambrian period, the time when most major groups of animals first evolved. Scientists had once thought only microbes and simple multicellular animals that existed prior to the Cambrian, but that notion is changing, said Ohio State University Professor Loren Babcock.

“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,” Babcock said. “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.”

Soo-Yeun Ahn, a doctoral student at Ohio State, presented the discovery today at a meeting of the Geological Society of America.

Babcock was surveying rocks in the mountains near Goldfield, Nevada, with Hollingsworth in 2000 when he found the tracks.

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