Scientists have identified the earliest known animal in the geological record.
It's a 558-million-year-old oval-shaped creature that may have borne a superficial resemblance to a segmented jellyfish.Researchers found specimens of the creature, known as Dickinsonia, that were so well preserved they still contained molecules of cholesterol.
This fat is a hallmark of animal life, the team reports in the journal Science.
Dickinsonia belongs to a group of life forms known as the Ediacaran biota. They were the first complex multi-cellular organisms to appear on Earth.
But they have been extremely difficult to classify, and their position on the tree of life has been one of the greatest mysteries in palaeontology.
Different teams of scientists have variously classified them as lichens, fungi, protozoans, evolutionary dead-ends and even as an intermediate stage between plants and animals.
The new analysis of a specimen found in north-west Russia places Dickinsoniafirmly within the animal kingdom.
Read more here: BBC