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".
For comparison, non-bilateral animals include sponges, corals, jellyfish, and anemones.
Life during the Ediacaran was characterized by algae, lichens, giant protozoans, worms, and various bacteria, but there's still a lot that paleontologists don't know about it. The footprints are present in parallel tracks in the mud.
It is believed most major animals capable of leaving footprints appeared during and after this event, but many have suspected there might be some more ancient fossils that could reveal the evolutionary ancestry of the animals that thrived later.
Still, this discovery means that paleontologists will have to revise their vision of how life developed in Earth's primordial oceans.
Scientists from the Chinese Academy of Sciences' Nanjing Institute of Geology and Paleontology and Virginia Tech have teamed together to find the prints and analyze them.
However, this creature - which provides the earliest evidence of an animal with legs - would have existed around 10 million years before then.
"Previously identified footprints are between 540 and 530 million years old".
These trace fossils represent some of the earliest known evidence of animal appendages and extend the earliest trace fossil record of animals with appendages from the early Cambrian to the late Ediacaran Period. They are one of the most diverse animal groups in existence today.
Still, due to the proximity of the track marks to fossilised burrows discovered nearby, the researchers hypothesise the creature may have exhibited "complex behaviour", such as periodically digging into sediments to mine oxygen and food among its riverbed habitat.
'Arthropods and annelids, or their ancestors, are possibilities. The team is involved in researching about the tracks and burrows found in the Denying Formation. No fossils has been found in the fossil record, and the odds are it never will be found - it was a stroke of luck that the tracks were even preserved.