Langurs are a group of leaf-eating monkeys that are found across south east Asia.
The newly described animal is known for its distinctive spectacle-like eye patches and greyish-coloured fur.
Early explorers to Burma collected the monkey specimens, which had never been examined in detail.
The researchers extracted DNA and measured physical features such as tail and ear length, which they compared with those of wild populations.
This revealed a new species, the Popa langur, which is found only in patches of forest in the centre of the country. Most live in a wildlife sanctuary park on the slopes of the sacred pilgrimage site of Mount Popa.
Describing the species scientifically will help in its conservation, said Frank Momberg of the conservation group Fauna & Flora International.
He told BBC News: “The Popa langur, just newly described, is already critically endangered and facing extinction so it’s absolutely critical to protect the remaining population and to engage with local communities as well as private sector stakeholders to safeguard its future.”
There are only 200 to 250 animals of the new species, which live in four isolated populations.
In the last decade or so, Myanmar has opened up to international collaborations with scientists, which has led to the discovery of species new to science.