Professor Lee Berger kisses a replica of the skull of a Homo Naledi , a newly discovered human ancestor during the unveiling of the discovery on September 10, 2015 in Maropeng. A new species of human ancestor, Homo naledi, estimated at about 2.5 to 2.8 million years old was discovered at the 'Cradle of Humankind', about 50 kilometres northwest of Johannesburg. At about 5 feet tall and only 100 or so pounds, and with a brain only about the size of an average orange, H. naledi is a startling combination of australopith-like and human-like features that, until now, was entirely unknown to science, researchers said. AFP PHOTO/STEFAN HEUNIS        (Photo credit should read STEFAN HEUNIS/AFP/Getty Images)