A mysterious species of ancient human has been discovered in a cave in southern Siberia.
Nicknamed X-Woman, scientists say the human lived alongside our ancestors tens of thousands of years ago.
The discovery, which could rewrite mankind's family tree, was made after analysis of DNA from a fossilised finger bone.

This skull was fashioned from a skull and jaw found in the remains of 17 pre-humans (nine adults, three youths and five children) which were discovered in the Afar Region of Ethiopia in 1975. They are believed to have lived 3.2million years ago

Meet 'Mrs Ples' who was unearthed in Sterkfontein, South Africa in 1947. Her whole skull was found and it is believed she lived 2.5million years ago. Sediment traces found on the inside of her skull indicate to scientists that she died by falling into a chalk pit

The skull of this male adult was found on the western shore of Lake Turkana in Kenya in 1985. He is believed to have lived in 2.5million years ago. The shape of the mouth indicates that he had a strong bite and that he could chew sinewy plants

This species of sub-human - Homo rudolfensis - was found in Koobi Fora, Kenya, in 1972. The adult male is believed to have lived about 1.8million years ago. He used stone axes ate meat and plants and lived on the wooded edge of Lake Turkana in Eastern Africa

Researchers shaped this skull on the basis of this discovery of 'Zinj' in 1959. The adult male lived 1.8million years ago in the Olduvai Gorge of Tanzania. He would have fed himself on seeds, plants and roots which he dug out with bones

The near-complete skeleton of 'Turkana Boy', a male adolescent aged about 13, was found in Nariokotome, Kenya, in 1984. He lived 1.6million years ago. His teeth and skull bear a close resemblance to discoveries in Asia of homo erectus

Experts are often forced to resort to educated guesswork to fill in the gaps in research to come up with images of human ancestors.
Each new discovery means paleoanthropologists have to rethink the origins of man's ancestors.
The previously held concept of primitive man - characterised by a large brain and the ability to manufacture tools - has had to be changed by researchers.
European natives of primitive man, homo heidelbergensis, are believed to have been able to make perfect javelins from wood 400,000 years ago and are also thought to have had the ability to plan for the future.
Neanderthals are also now thought to have had far more culture and craft skills than earlier research indicated.