In a study published in Zoological Research, scientists described the species for the first time. The Popa langur (Trachypithecus popa) is a type of langur, or leaf-eating monkey, with a black face and white circles around the eyes, according to BBC News. But there are only 200 to 250 of the animals left in the wild, and they live in four isolated populations.

"Sadly this is a bittersweet discovery due to the limited number of individuals left in the wild and fragmented populations," Roberto Portela Miguez, a study coauthor and the senior curator at the London Natural History Museum, said, as CNN reported.

The Popa langur was discovered in a surprising way, according to an AFP article published in The Guardian. A genetic analysis of a more-than 100 year old specimen held at London's Natural History Museum revealed that it was a distinct species. The museum specimen matched more recent bones gathered in the field in Myanmar. The monkeys were filmed for the first time in 2018.

"Monkeys are one of the most iconic groups of mammals, and these specimens have been in the collections for over a hundred years," Miguez said in a museum press release. "But we didn't have the tools or the expertise to do this work before. It is thanks to this collaboration with multiple international colleagues and latest sequencing techniques that we manage to bring this species to light."

The research was a collaboration between the museum, Flora & Fauna International, and the German Primate Centre.

There are more than 20 species of langur in the world, according to AFP, and several are already endangered. The Popa langur takes its name from Myanmar's Mount Popa, a pilgrimage site that is home to the species' largest population, CNN reported. That population has more than 100 individuals.

Luckily, Mount Popa is already home to a wildlife sanctuary, but Miguez said that hunting and deforestation still occur there.

Overall, habitat loss is the greatest threat to the new species, which once lived throughout Myanmar.

"Hunting is a big problem but the bigger threat is the habitat is almost gone and it is reduced, fragmented and isolated due to human encroachment, " Christian Roos of the German Primate Centre told BBC News.

However, the scientists said that the discovery of the new species will help with its conservation.

"The hope is that by giving this species the scientific status and notoriety it merits, there will be even more concerted efforts in protecting this area and the few other remaining populations," Miguez said in the museum release. "At least whatever decisions are made in the future when it comes to things like how the parks are managed, those [will] be from a more informed point of view as we now know of the distinctiveness of the population of langurs that is actually there."

Past history gives reason for hope, Flora & Fauna International pointed out. A decade ago, the organization discovered the Myanmar snub-nosed monkey and realized there were only 260 to 330 of the animals left. But they worked with the Myanmar government and local communities to help the species. The Myanmar government just declared its mountain forest habitat a protected area this year.

"It is hoped that by engaging with communities, and with business interests whose areas of operation overlap with the Popa langur's limestone habitat, we will pave the way for appropriate action to protect this particular primate in perpetuity," the conservation organization wrote.