Earliest animal fossil footprints discovered in China

Earliest animal fossil footprints discovered in China

The fossil tracks offer "some of the earliest known evidence for animal appendages and extend the earliest trace fossil record of animals with appendages from the early Cambrian (485 million to 541 million years ago) to the late Ediacaran Period".

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

Because the footprints are trace fossils, not fossils of the animal itself, it's going to be hard to credit a particular branch of the Tree of Life with the title of "First to Develop Limbs".

The tracks are from the Ediacaran Period, making them the first prints left by animals from that period.

The footprints, belonging to an unknown invertebrate, date back to around 541 million years ago. Those footprints were dated to be between 11,000 and 14,000 years old, making them twice as old as the earliest human civilization.

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.

Professor Shuhai Xiao, senior author of the study and geobiologist at Virginia Tech University, said their findings allow them to understand what species were first to evolve with legs. "The new fossils are probably up to 10 million years older". They observed the trackways, which were not regular, and after analyzing their characteristics, they reached the conclusion that these were formed by bilaterian animals with paired appendages.

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.

Bilaterians are one of the most common body types in the world, now and throughout history, but previous fossil evidence for them only goes back as far as the Cambrian. They are one of the most diverse animal groups in existence today.

The trackways appear to be connected to burrows, suggesting that the animals may have periodically dug into sediments, perhaps to mine oxygen and food.

The researchers don't yet know exactly what animal left these tracks, and unfortunately we may never know.

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

Now, the discovery of the trackways and burrows shows that animals with appendages lived during the Ediacaran period, the researchers said.

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