By examining the molecular remains of what the animals ate, the researchers were able to confirm the slug-like organism, known as Kimberella, had a mouth and a gut and digested food the same way modern animals do.
"Our findings suggest that the animals of the Ediacara biota, which lived on Earth prior to the 'Cambrian Explosion' of modern animal life, were a mixed bag of outright weirdos, such as Dickinsonia, and more advanced animals like Kimberella that already had some physiological properties similar to humans and other present-day animals," lead author Dr Ilya Bobrovskiy, from GFZ-Potsdam in Germany, said.
Both Kimberella and Dickinsonia, which have a structure and symmetry unlike anything that exists today, are part of the Ediacara biota family that lived on Earth about 20 million years prior to the Cambrian Explosion -- a major event that forever changed the course of evolution of all life on Earth.
"Ediacara biota really are the oldest fossils large enough to be visible with your naked eyes, and they are the origin of us and all animals that exist today.
Nearly all fossils that came before the Ediacara biota were single-celled and microscopic in size," Professor Brocks said.
Cholesterol is the hallmark of animals and it's how, back in 2018, the ANU team was able to confirm that Ediacara biota are among our earliest known ancestors.
The molecules contained tell-tale signatures that helped the researchers decipher what the animals ate in the lead up to their death.
"Kimberella knew exactly which sterols were good for it and had an advanced fine-tuned gut to filter out all the rest.
Dr Bobrovskiy retrieved both the Kimberella and Dickinsonia fossils from steep cliffs near the White Sea in Russia a remote part of the world home to bears and mosquitoes in 2018
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