Earliest animal footprints found in China

  • Earliest animal footprints found in China

Earliest animal footprints found in China

This remarkable discovery is hailed in a study, published yesterday in the journal Science Advances by a research team from Virginia Tech University in the USA and the Nanjing Institute of Geology and Palaeontology (NIGP) of the Chinese Academy of Sciences.

The 550-million-year-old tracks measure only a few millimetres in width, and consist of two rows of imprints arranged in what the researchers describe as a "poorly organised series or repeated groups", which could be due to variations in gait, pace, or interactions with the surface of what was once an ancient riverbed. That's hundreds of millions of years before dinosaurs started roaming Earth, about 245 million years ago.

The characteristics of the trackways indicated that they were produced by bilaterian animals with paired appendages that raised the animal body above the water-sediment interface.

However, this creature - which provides the earliest evidence of an animal with legs - would have existed around 10 million years before then.

Researchers believe they may have been a type of arthropod - the family of animals with jointed limbs that includes insects and crustaceans, or something akin to a legged worm.

Until now, there had been no evidence of limbed creatures prior to the Cambrian Explosion, say the researchers from Virginia Tech in the US. 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.

But these new fossils date back to the Ediacaran Period, which lasted between 635 and 541million years ago. Until the current discovery, however, no fossil record of animal appendages had been found in the Ediacaran Period. Take that, rest of the pre-Cambrian life forms!

"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.

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 animal appears to have paused from time to time, since the trackways appear to be connected to burrows that may have been dug into the sediment, "perhaps to mine oxygen and food", said the report.

The researchers speculate that the same creature left both the tracks and the burrows, suggesting an animal that scurried and tunneled its way across the ground.