Scientists find 540-million-year-old animal footprints

Earliest animal footprints found in China – study

'Earliest animal fossil footprints discovered in China'

The paleontological team found two rows of footprints that represent not only the earliest footprints ever found but also the earliest known record of an animal with legs.

These trackways, preserved near burrows, were discovered in Dengying Formation - a rich fossil preserve in China's south - and constitute the first evidence confirming that an ancient group of animals called bilateria actually pre-dates the Cambrian explosion. However, Xiao said they are uncertain if the creature belonged to the arthropod family or whether it has many or two legs.

Multicellular life got its start in the Early Ediacaran Period about 635 million years ago, perhaps buoyed by the melting of "Snowball Earth".

Until the current discovery, however, no fossil record of animal appendages had been found in that period.

Researchers on the study came from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences, and Virginia Tech in the United States.

The study is published June 6 in the journal Science Advances.

The shape of the tracks suggest they were made by bilaterian animals with pairs of legs and a raised body. As the Inquisitr previously reported, up until that historic event, which lasted for 20-25 million years and gave rise to most of the major animal groups on the planet, animal life on Earth was limited to simpler, single-celled or multicellular organisms.

"Previously identified footprints are between 540 and 530 million years old".

Professor Shuhai Xiao, a geobiologist at Virginia Tech University, told The Guardian: "Animals use their appendages to move around, to build their homes, to fight, to feed, and sometimes to help mate".

The Ediacaran was the period immediately before the Cambrian Explosion (541 million to 510 million years ago), a time when life underwent rapid diversification.

"If an animal makes footprints, the footprints are depressions on the sediment surface, and the depressions are filled with sediments from the overlying layer".

The trackways were also connected to the burrows which just strengthened the hypothesis that they were left by animals who dug burrows in the sediment for food.

"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)", he added.

'Arthropods and annelids, or their ancestors, are possibilities.

Animals with bilaterally paired appengages are assumed to have appeared during the Cambrian Explosion, but now their ancestry may be traceable to even further back in history.

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