Earliest animal footprints found in China


An worldwide research team discovered the fossil tracks in China dating back to the Ediacaran Period, just before the Cambrian Explosion when life on Earth increased rapidly.

Further, the footprints left behind by its multiple feet suggest that this sea-dwelling animal had paired appendages that raised its body above the ocean floor.

Unfortunately for scientists, the creature that made the footprints did not die nearby and leave an equally well preserved fossil to be studied.

The Cambrian Explosion, around 541 million years ago, was a period when a wide variety of animals burst onto the evolutionary scene.

Animals use their appendages or outgrowths to move around, make their homes, feed, and find mates.

Without a complete fossil record though, any presumptions about the animal's habits or needs are pure speculation. The fossils date back to almost 3.5 billion years ago and are strong evidence of the earliest life that existed on Earth.

An global team of researchers is claiming to have discovered the world's oldest footprints.

The rock layers where the fossils were found date between 551 million and 541 million years ago, suggesting the footprints were made some time between those dates.

As Xiao explains, knowing when the first legged animal appeared on Earth is a crucial detail, considering that the movement of sediments triggered by that first walking creature as it trotted over our planet's surface could have had a major impact on the Earth's geochemical cycles and climate.

The teams consisted of Chinese Academy of Sciences' Nanjing Institute of Geology and Paleontology alongside colleagues from Virginia Tech.

Senior author Shuhai Xiao, who is a geobiologist at the Virginia Tech University, says that the new discovery is a crucial step in identifying the first ever animal that grew a pair of legs. The research was published in Science Advances on June 6, 2018.

They took a close look at the irregular trackways and witnessed two parallel rows of footprints, which appeared to have been arranged in a series or repeated groups.

"They were probably made by millimeter-sized animals with bilateral appendages and can provide important insights into early bilaterian evolution and behaviors".

He also said that arthropods and annelids or their ancestors are possible.

That's largely because Ediacaran life hadn't yet evolved the kinds of hard bones and shells that fossilize easily, so scientists usually have to rely on trace fossils instead - burrows, tracks and other secondary evidence of their existence.