Scientists Find Oldest Footprints On Earth That Date Back Up To 551 Million Years

Hundreds of millions of years ago, ancient creatures started emerging from the ground and learning to walk on a pair of appendages.

These animals are long gone and extinct, but they've made their mark on ancient rocks, making it possible for scientists to piece together the world back then.

Today, a crucial piece of the puzzle emerges as scientists unearthed the oldest known fossil footprints in history, revealing that bilaterian animals existed millions of years earlier than initially thought.

The First Animal That Walked The Earth

In a new study published in the journal Science Advances on Wednesday, June 6, researchers reveal that the newly discovered footprints were found in rocks that were 551 million to 541 million years old. This means that they lived during the Ediacaran Period, which lasted from 635 to 541 million years ago.

Scientists from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences and Virginia Tech reveal in a statement that the footprints were produced by a bilaterian creature with paired appendages that lifted its body above water-sediment surface.

The trackways were reportedly leading to burrows, where researchers say it's possible the animal may have dug for food or oxygen.

These groundbreaking trace fossils were discovered in the Dengying Formation at the Yangtze Gorges region of southern China.

Animals On Foot Go Further Than Thought

Bilaterian animals used to be believed to have appeared in the Cambrian Period — the oldest footprints found used to be just 540 and 530 million years old — but now the fossils suggest that they've existed long before that in the Ediacaran Period.

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.

"Animals use their appendages to move around, to build their homes, to fight, to feed, and sometimes to help mate," he tells The Guardian, pointing out that the resulting movement of sediments may have had an effect on the planet's geochemical cycles and climate.

"It is important to know when the first appendages appeared, and in what animals, because this can tell us when and how animals began to change to the Earth in a particular way."

While the footprints were well-preserved, scientists don't know exactly what animal made the tracks since there were no body fossils found in the site.

"At least three living groups of animals have paired appendages (represented by arthropods, such as bumblebees; annelids, such as bristle worms; and tetrapods, such as humans)," Zhe Chen, coauthor of the study from the Chinese Academy of Sciences, tells AFP as reported by BBC News. "Arthropods and annelids, or their ancestors, are possibilities."