Scientists involved in a groundbreaking new study have found evidence of the most ancient signs of molecular life, revealing that multicellular animals were alive and well 635 million years ago, 100 million years before they were first believed to exist. However, the evidence for this life did not come through bones but instead was found through a very special kind of chemical evidence.
As Inverse reports, international scientists discovered a new biomarker that came from the Animalia kingdom from between 660 and 635 million years ago, which to date is the oldest definitive evidence of animals that have been found.
This biomarker was observed in oils and rocks in India, Oman, and Siberia and is known as 26-methylstigmastane, which is a steroid compound. These days, such a marker is only seen in demosponges, and the new research is proof that these demosponges were living hundreds of millions of years ago, according to first author Alex Zumberge.
“This steroid biomarker is the first evidence that demosponges, and hence multicellular animals, were thriving in ancient seas as far back as 635 million years ago.”
At the present time, demospongia can be counted as the world’s most diverse variety of sponge as there are no less than 8,000 types of these that have been accounted for so far. These invertebrates are richly vivid in color and are able to both asexually and sexually reproduce, leading them to thrive. Even though sponges do have skeletons, these are not usually left behind in terms of fossils that can be discovered. Fortunately for scientists, stable biomarkers are still around to prove their existence 635 million years ago.
Oldest-Ever Evidence of Animal Life Shifts Timeline of Organism Evolution: https://t.co/LmBMhKUaLR— Inverse (@inversedotcom) October 15, 2018
This new study is crucial in that it has determined that 100 million years before the Cambrian explosion 540 million years ago there were multicellular animals that were around. Scientists were once convinced that before this period of time, any organisms that may have existed would almost certainly have been individual-celled creatures that were inherently simple in nature. However, this research has shown that animals similar to today were actually living happily in seas around various regions of the world, and this can now be proven through chemical analysis rather than the study of fossils.
Before this discovery, what was previously believed to be the most ancient animal fossil, which was calculated to be a 558-million-years-old ribbed oval, was found through organic material that had been preserved over hundreds of millions of years. It is now strongly suspected that demosponges of the variety that were recently studied may have even been alive during the Cryogenian period, which dates back from 720 to 635 million years ago.
The new study which demonstrates that multicellular animals existed 635 million years ago has been published in Nature Ecology & Evolution.