Last year, the IUCN classified Bornean orangutans as critically endangered due to a precipitous population decline caused by destruction of their forest habitat for palm oil and pulp wood plantations. Previously, scientists have recognized six great ape species: Sumatran and Bornean orangutans, eastern and western gorillas, chimpanzees and bonobos.
This prompted the researchers to conduct what they called the "largest genomic study of wild orangutans to date", comparing the genes from the recovered orangutan with data collected in the past from other field sites on Sumatra.
Zurich researchers said the new species also has become one of the most endangered as well, with roughly about 800 remaining in the upland forest region of North Sumatra.
Following the discovery of the skeletal material, believed to have come from a Tapanuli orangutan killed in a human-animal conflict in 2013, an global team of researchers set out to understand more about the distant ape relative of humans.
Move over, Bornean and the Sumatran orangutans.
An global team of researchers from 34 institutions, led by anthropologist Alexander Nater of the University of Zurich in Switzerland, pursued two lines of evidence to determine if the ape colony was different enough from the two already acknowledged orangutan species - known as the Bornean and Sumatran - to be defined as a third. The oldest evolutionary line in the genus Pongo is actually found in Tapanuli orangutans, which appear to be direct descendants of the first Sumatran population in the Sunda archipelago.More news: Israeli army offers rare pledge of help to embattled Syrian Golan village
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To verify the morphological and genetic examination, the team employed a complex computer model which revealed that the Tapanuli population must have been isolated from other Sumatran populations of orangutans for least 10,000 to 20,000 years.
Erik Meijaard of the Australian National University said: "Great apes are among the best-studied species in the world".
By the latest estimate, there should be no more than 800 individuals belonging to the new orangutan species. The paper suggests that a mortality rate of even 1 percent per year could drive this newly identified orangutan species to extinction.
"It isn't an everyday event that we find a new species of great ape, so indeed the discovery is very exciting", Michael Krutzen, an anthropologist at the University of Zurich in Switzerland, said in a news release.
A new species of orangutan has been found hidden from the rest of the world in remote jungle in Indonesia.
"It's very worrying", said Prof Wich, "to discover something new and then immediately also realise that we have to focus all of our efforts before we lose it".