The BBC reports that the Director of Department of Genetics at the Max Planck Institute for Evolutionary Anthropology, Svante Pääbo has discovered a new type of prehistoric human in a Siberian cave in the Altai mountains: ‘Scientists say an entirely separate type of human identified from bones in Siberia co-existed and interbred with our own species. The ancient humans have been dubbed Denisovans after the caves in Siberia where their remains were found. There is also evidence that this group was widespread in Eurasia. A study in Nature journal shows that Denisovans co-existed with Neanderthals and interbred with our species – perhaps around 50,000 years ago. An international group of researchers sequenced a complete genome from one of the ancient hominins (human-like creatures), based on nuclear DNA extracted from a finger bone’, as related by Pallab Ghosh, the BBC Science Correspondent. Ghosh continues that, ‘[a]ccording to the researchers, this provides confirmation there were at least four distinct types of human in existence when anatomically modern humans (Homo sapiens sapiens) first left their African homeland. Along with modern humans, scientists knew about the Neanderthals and a dwarf human species found on the Indonesian island of Flores nicknamed The Hobbit. To this list, experts must now add the Denisovans. The implications of the finding have been described by Professor Chris Stringer of the Natural History Museum in London as “nothing short of sensational”. Scientists were able to analyse DNA from a tooth and from a finger bone excavated in the Denisova cave in southern Siberia. The individuals belonged to a genetically distinct group of humans that were distantly related to Neanderthals but even more distantly related to us. The finding adds weight to the theory that a different kind of human could have existed in Eurasia at the same time as our species’. Yesterday, the BBC World Service programme Science in Action updated the story: ‘Scientists have sequenced the genome of an ancient hominid female from just the finger-bone found in Denisova cave in southern Siberia. She is nicknamed ‘X Woman’ – thought to have been living in Central Asa around 48,000 and 30,000 years ago. Earlier in the year, analysis of the mitochondrial DNA, which is only inherited down the maternal line, revealed that these ‘Denisovans’ shared a common ancestor with modern humans and Neanderthals about one million years ago, but that it was unlikely to have interbred with our direct ancestors and those of our ancient cousins. Now, having decoded the nuclear DNA and have much more information about this possibly new species’.
So, it turns out that four humanoid beings have at one stage dwelled on this planet: Neanderthals, a dwarf human species (nicknamed Hobbits), Denisovans, and modern humans . . . As such, I had been completely unaware of the dwarf species: ‘Homo floresiensis (“Flores Man”, nicknamed “hobbit”) is a possible species, now extinct, in the genus Homo. The remains were discovered in 2004 on the island of Flores in Indonesia. Partial skeletons of nine individuals have been recovered, including one complete cranium (skull). These remains have been the subject of intense research to determine whether they represent a species distinct from modern humans, and the progress of this scientific controversy has been closely followed by the news media at large. This hominin is remarkable for its small body and brain and for its survival until relatively recent times (possibly as recently as 12,000 years ago). Recovered alongside the skeletal remains were stone tools from archaeological horizons ranging from 94,000 to 13,000 years ago’, as the requisite Wiki entry informs us.
The Observer’s science editor Robin McKie explains that ‘[i]t remains one of the greatest human fossil discoveries of all time. The bones of a race of tiny primitive people, who used stone tools to hunt pony-sized elephants and battle huge Komodo dragons, were discovered on the Indonesian island of Flores in 2004. The team of Australian researchers had been working in a vast limestone cavern, called Liang Bua, in one of the island’s remotest areas, when one scientist ran his trowel against a piece of bone. Carefully the group began scraping away the brown clay in which pieces of a tiny skull, and a little lower jaw, were embedded. This was not any old skull, they quickly realised. Although small, it had special characteristics. In particular, it had adult teeth. “This was no child, but a tiny adult; in fact, one of the smallest adult hominids ever found in the fossil record,” says Mike Morwood, of Australia’s University of Wollongong and a leader of the original Flores expedition team. The pieces of bone were carefully wrapped in newspaper, packed in cardboard boxes and then cradled on the laps of scientists on their journey, by ferry and plane, back to Jakarta. Then the pieces of skull, as well as bones from other skeletons found in Liang Bua, were put together. The end result caused consternation. These remains came from a species that turned out to be only three feet tall and had the brain the size of an orange. Yet it used quite sophisticated stone tools. And that was a real puzzle. How on earth could such individuals have made complex implements and survived for aeons on this remote part of the Malay archipelago? Some simply dismissed the bones as the remains of deformed modern humans with diseases that had caused them to shrink: to them, they were just pathological oddities, it was alleged. Most researchers disagreed, however. The hobbits were the descendants of a race of far larger, ancient humans who had thrived around a million years ago. These people, known as Homo erectus, had become stranded on the island and then had shrunk in an evolutionary response to the island’s limited resources. That is odd enough. However, new evidence suggests the little folk of Flores may be even stranger in origin. According to a growing number of scientists, Homo floresiensis is probably a direct descendant of some of the first apemen to evolve on the African savannah three million years ago. These primitive hominids somehow travelled half a world from their probable birthplace in the Rift Valley to make their homes among the orangutans, giant turtles and rare birds of Indonesia before eventually reaching Flores’.
And now, yet another hominid species has been discovered in the Altai mountains. Dr Richard Green, from the University of California, Santa Cruz, has been investigating the DNA of the newly discovered species. The Daily Mail’s David Derbyshire explains that this ‘new species appears to have been a ‘sister group’ to the Neanderthals and its discovery paints a complicated picture of human evolution and migration out of Africa – the cradle of mankind. Dr Green believes one group of early human ancestors left Africa between 300,000 and 400,000 years ago and quickly split up. One branch evolved into the Neanderthals who spread into Europe, while the other moved east and became Denisovans’.
Derbyshire continues that ‘[a]round 70,000 years there was another wave of migration when modern humans quit Africa. These were our ancestors and they first encountered and interbred with Neanderthals – leaving traces of Neanderthal DNA in the genetic code of all non-Africans alive today. One group of modern humans later came into contact with Denisovans, leaving traces of Denisovan DNA in the humans who settled in Melanesia’. Bence Viola, an anthropologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, adds these insights to the debate: “We don’t think the Denisovans went to Papua New Guinea. We think the Denisovan population inhabited most of eastern Eurasia in the same way that Neanderthals inhabited most of western Eurasia. Our idea is that the ancestors of Melanesians met the Denisovans in Southeast Asia and interbred, and the ancestors of Melanesians then moved on to Papua New Guinea”.
 Pallab Ghosh, “Ancient humans, dubbed ‘Denisovans’, interbred with us” BBC News (22 December 2010).
 Pallab Ghosh, “Ancient humans, dubbed ‘Denisovans’, interbred with us”.
 David Derbyshire, “There were THREE types of ancient humans”.