Three human species 'co-existed two million years ago'
9 August 2012 Last updated at 15:08 BST
Scientists in Kenya believe they have made another step forward in their quest to find out how humans evolved.
Three fossils unearthed in a part of Kenya known as the "cradle of mankind" have given researchers an almost complete face of an early human.
They think they can confirm their theory that there are two additional pre-human species besides the one that eventually led to modern humans.
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