A new study has revealed the discovery of 600 million years old fossil in central Guizhou Province of South China, suggesting that complex multi-cellular life existed 60m yrs before skeletal animals appeared on Earth during the Cambrian Explosion.
Geobiologist Shuhai Xiao from Virginia Tech College of Science said that this opened up a new door for them to shine some light on the timing and evolutionary steps that were taken by multicellular organisms that would eventually go on to dominate the Earth in a very visible way.
Xiao added that fossils similar to these have been interpreted as bacteria, single-cell eukaryotes, algae, and transitional forms related to modern animals such as sponges, sea anemones, or bilaterally symmetrical animals, but this paper lets them put aside some of those interpretations.
Xiao and his collaborators looked at phosphorite rocks from the Doushantuo Formation and recovered three-dimensionally preserved multicellular fossils that showed signs of cell-to-cell adhesion, differentiation, and programmed cell death, which are qualities of complex multicellular eukaryotes such as animals and plants.
The discovery sheds light on how and when solo-cells began to cooperate with other cells to make a single, cohesive life form and the complex multicellularity evident in the fossils is inconsistent with the simpler forms such as bacteria and single-celled life typically expected 600 million years ago.
The study is published online in the journal Nature.