Science

US, Chinese scientists find oldest animal tracks

US, Chinese scientists find oldest animal tracks

Although it's not clear what animal left these ancient tracks behind - since only the trace fossils (evidence that an animal has been there) were discovered, and not the fossils themselves - the footprints date back 551 million to 541 million years ago, to the Ediacaran Period.

An global 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. They published their findings Wednesday in the journal Science Advances.

This means that the symmetrical creature appeared before the Cambrian Period, Chen noted.

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.

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.

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.




The trackways were found in the Yangtze Gorges area of South China.

"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", Xiao said.

However, until now, no records of such fossils were ever found. Researchers from the Chinese Academy of Sciences' Nanjing Institute of Geology and Palaeontology, together with colleagues from Virginia Tech in the U.S., studied the trackways and burrows that were discovered in a fossil-rich area close to the Yangtze River.

Dr Shuhai Xiao of Virginia Tech said, 'If an animal makes footprints, the footprints are depressions on the sediment surface, and the depressions are filled with sediments from the overlying layer.

Researchers do not know what animals made the footprints but have interpreted the two parallel rows of dots as rows of tracks.

He added: "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)". The team is involved in researching about the tracks and burrows found in the Denying Formation. Maybe they were never preserved.