NEWLY IDENTIFIED ORANGUTAN IS WORLD’S MOST ENDANGERED GREAT APE SPECIES
A population of orangutans that lives in a remote part of northern Sumatra, and that was only discovered in 1997, has now been identified as a separate species. With only around 800 individuals known to exist, it’s now also the most threatened of all great ape species.
It was once believed that all orangutans were one species, but since 1996 science has recognised two: the Bornean and Sumatran orangutan (Pongo pygmaeus and Pongo abelli, respectively). The following year, a long-rumoured population of orangutans living in the Batang Toru region of northern Sumatra was seen for the first time, but initially the apes were thought to be of the species P. abelli.
However, close study of an adult skeleton found in 2013 has revealed significant differences in the skull and teeth of the Batang Toru apes, leading to their new classification: Pongo tapanuliensis, or the Tapuli orangutan. Genomic analysis suggests that the species must have split from
P. abelli around 70,000 years ago.
“The Batang Toru orangutans appear to be direct descendants of the initial orangutans that had migrated from mainland Asia, and thus constitute the oldest evolutionary line within the genus Pongo,” said lead author Alexander Nater, from the University of Zurich.
With just 800 individuals known,
P. tapanuliensis goes straight to the top of the endangered great apes league table, not least because large areas of its habitat are threatened by plans to build a hydroelectric dam in the region. The discovery isn’t great news for P. abelli in that regard, either – there are now 800 less of them than was previously believed.
Above: Closer examination of a skeleton found in 2013 has revealed that
P. tapanuliensis is a separate species