The world's oldest animal dating back 558 million years has been unearthed in Russia this week (September 19).<br /><br />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.<br /><br />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.<br /><br />Scientists have described the game-changing discovery as the 'Holy Grail' of palaeontology.
