A new species of orangutan has been discovered and it is already endangered.
The Tapanuli orangutan has been found living in the forests of North Sumatra in Indonesia, but there are only 800 of the mammals left, leading scientists to fear that the new species could be both discovered and become extinct in their lifetimes.
Tapanuli orangutans were originally considered to be part of the Sumatran orangutan population, but the discovery that it is actually part of a separate species means it is the most endangered of all the great apes.
The realisation that a new species of orangutan had been discovered came about after Pongo tapanuliensis bones were discovered and its skull was found to be "potentially unique".
Subsequent tests showed that it had larger canine teeth than those of other orangutans.
Researchers then conducted the largest ever genomic analysis, which involved a comparison of genomic features such as DNA sequence, structural variation and gene expression, on wild orangutans and found evidence pointing to a third species.
Anton Nurcahyo, a PhD student from the Australian National University, who worked on the study told how researchers "were completely surprised to find that the skull is quite different in some characteristics from orangutan skulls we had seen before."
He added: "It has a smaller skull, but larger canine teeth than other orangutan species."
It was only in 1996 that orangutans were found to not be one single species, but two: Bornean and Sumatran.
The latest research published in Current Biology has now widened that to three.
Dr Maja Mattle-Greminger, of the University of Zurich, who led the genomic analysis along with Dr Alexander Nater, said: "For quite some time, we had been working on genomic data to investigate the genetic structure and evolutionary history of all existing orangutan populations.
"One consistent result was that we identified three very old evolutionary lineages among all orangutans, despite only having two species currently described".
The discovery promoted Dr Nater to carry out extensive computer modelling to reconstruct the population history of orangutans in the region.
His analysis suggested the Tapanuli orangutans, found in the Batang Toru forest area of the island, may have been isolated from other Sumatran populations for at least 10-20,000 years.
Professor Serge Wich, of Liverpool John Moores University, who provided ecological expertise to the study, said: "It is incredibly exciting that a new orangutan species has been described and it's a wonderful addition to Indonesia's high biodiversity.
"At the same time the low number of Tapanuli orangutans in the wild indicates that there can be no complacency in terms of its conservation.
"If steps are not taken quickly to reduce current and future threats to conserve every last remaining bit of forest, we may see the discovery and extinction of a great ape species within our lifetime."