The discovery near Lake Turkana in Kenya confirms that a fossil skull found 40 years ago was a different species of early Homo living alongside Homo erectus during the Pleistocene epoch.
That skull, dubbed KNM-ER 1470, missing the teeth and lower jaw but distinguished by a large brain size and long flat face, started a longstanding debate about just how many different relatives of early man lived during that period.
Two new fossils may have settled the debate, the National Geographic Society, which funded the research, said in a release Wednesday.
"For the past 40 years we have looked long and hard in the vast expanse of sediments around Lake Turkana for fossils that confirm the unique features of 1470's face and show us what its teeth and lower jaw would have looked like," Meave Leakey, a National Geographic explorer-in-residence, said. "At last we have some answers."
The new fossils include a face, a remarkably complete lower jaw, and part of a second lower jaw.
"Combined, the three new fossils give a much clearer picture of what 1470 looked like," researcher Fred Spoor said. "As a result, it is now clear that two species of early Homo lived alongside Homo erectus.
"The new fossils will greatly help in unraveling how our branch of human evolution first emerged and flourished almost 2 million years ago."