The modern human lineage originated from the Homo Sapiens in Africa more than 2 million years ago but recent studies have revealed that two extinct human species used to live on the earth along with our ancestors.
From The Huffington Post:
Now fossils between 1.78 million and 1.95 million years old discovered in 2007 and 2009 in northern Kenya suggest that early Homo were quite a diverse bunch, with at least one other extinct human species living at the same time as H. erectus and H. habilis.
“Two species of the genus Homo, our own genus, lived alongside our direct ancestor, Homo erectus, nearly 2 million years ago,” researcher Meave Leakey at the Turkana Basin Institute in Nairobi, Kenya, told LiveScience.
A skull known as KNM-ER 1470 was found in Kenya in 1972 and researchers claimed it belonged to an extinct species they named Homo rudolfensis. A newly-discovered skull that was found 6 miles away from where KNM-ER 1470 was found could signify that both skulls belonged to a species that used to live alongside the Homo Sapiens.
According to Fred Spoor, a researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, the skull has “very flat facial features” and hints at the fact that Africa was “quite a crowded place” over two million years ago.