Something that many anthropologists speculated over for decades has been proven: a third species of human has been confirmed.
The confirmation came after extensive DNA testing of a 30,000 year old fossil. The discovery of a third type of human proves that Neanderthals and modern-day humans were not the only intelligent beings to walk the Earth tens of thousands of years ago.
The new species has been named "Denisovans" and they not only lived with our modern ancestors, but mated with them as well. Denisovans was chosen because the remains of the newly discovered species were found in the Denisova cave located in the Altai mountain range of Siberia during 2008.
Positive identification came from DNA samples extracted from a fragment of finger bone and a tooth. The finger bone belonged to a young girl that scientists dubbed the "X-Woman."
The fossilized tooth is similar to extremely old pre-humans—possibly Homo Erectus—that had been thought to have gone extinct one million years in the past. The tooth, however, opens the door to the possibility that Homo Erectus did not die out but merely evolved into what became the Denisovans.
Analysis revealed the finger fragment came from a five to seven-year-old girl. The remains were discovered next to personal jewelry.
The Denisovan people walked upright but were not thickset like Neanderthals, nor were they quite like Homo Sapiens either. Their distinct genetic pattern made them a third species of Man that lived amongst the other two species as late as the last major Ice Age. According to the researchers' paper published in the journal Nature, the finger and tooth came from two different individuals.
The study had a second breakthrough. The extracted DNA samples of the Denisovan matched DNA extracts present in the present day Melanesian. Melanesia is an island that lies to the east and north of the Australian continent.
The researchers theorize that the Denisovans must have interbred with ancestors of the Asians and the third species may have been widespread throughout the continent. If so, then many Asians carry the genes of the ancient Denisovans.
The idea that amongst some scientists is the hypothesis that a different kind of human might've co-existed in other human species in Eurasia. The discovery lends more credence to that possibility.
The important discovery was described by Professor Chris Stringer of the Natural History Museum in London as "nothing short of sensational." It changes the entire picture of ancient Man, evolution and the "family tree" that's becoming more and more complicated.
The breakthrough research was done by a scientific team at the Max Planck Institute in Leipzig, Germany. The effort was led by Professor Svante Paabo. Commenting on the research, Paabo simply stated: "A species of early human living in Europe evolved."
David Reich from the Harvard Medical School, worked with Svante Paabo on the study. In a BBC interview he said, "It is fascinating to see direct evidence that these archaic species did exist (alongside us) and it's only for the last few tens of thousands of years that is unique in our history that we are alone on this planet and we have no close relatives with us anymore."
The discovery has led some researchers to ask if a fourth species on Man might yet be found.