yorkfoto/iStockBy JULIA JACOBO, ABC News

(NEW YORK) -- Scientists have discovered a new species of monkeys in central Myanmar with the help of a 100-year-old tissue sample.

The primate, named Popa langur after the extinct volcano Mount Popa, has been "hiding in plain sight" in central Myanmar, according to the conservation organization Fauna & Flora International. The area of Mount Popa houses the largest population of the species.

The Popa langur is characterized by a dark brown or gray-brown back, with a sharply contrasting gray or whitish abdomen and black hands and feet, according to a new study published in the international scientific journal Zoological Research.

The species was once widespread in the central dry zone of Myanmar, researchers said. Only two populations of the monkeys were thought to have survived, one in Mount Popa and the other in Bago Yoma, but recent fieldwork has led to the discovery of three new populations, the researchers said. Scientists believe there are only about 200 to 250 living Popa langurs, and the species is considered to be critically endangered.

DNA was collected by researchers in the wild by fecal samples. Tissue samples, some a century old, were taken from the natural history museums in London, Leiden, New York and Singapore and used for the genetic analysis of the species, which proved that it had not been uncovered before.

Ten years ago, a team of primatologists lead by Fauna & Flora International discovered the snub-nose monkey in Myanmar. When found, the population of the "sneezing" monkey was between 260 and 330 living animals, but the scientists were able to work with local communities to safeguard the species' future, according to the organization.

The monkeys' survival is threatened by hunting, habitat loss, degradation and fragmentation caused by agricultural encroachment, illegal and unsustainable timber extraction and disturbances caused by collection of non-timber products and free cattle grazing, according to the study.

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