The world's oldest animal dating back 558 million years has been unearthed in Russia this week (September 19).

Our earliest ancestor was finally identified after traces of cholesterol were found on it, the blood fat that proves it is an animal, not a plant or other life form.

The fossil looks like a cross between a leaf and a thumbprint. The bizarre marine creature grew to almost four and a half feet long (1.4 metres), and almost as wide.

Scientists have described the game-changing discovery as the 'Holy Grail' of palaeontology.

The world's oldest animal dating back 558 million years has been unearthed in Russia. Our earliest ancestor was finally identified after traces of cholesterol were found on it, the blood fat that proves it is an animal, not a plant or other life form. Scientists have described the game changing discovery as the 'Holy Grail' of palaeontology. The fossil looks like a cross between a leaf and a thumb print. The bizarre marine creature grew to almost four and a half feet long (1.4 metres), and almost as wide.