A remote population of frizzy-haired orangutans on the Indonesian island of Sumatra seems to be a new species of primate, scientists say.

But the newest member of the family tree of advanced animals that include humans may not be around much longer. Their numbers are so small, and their habitat so fragmented, that they are in danger of going extinct, say the scientists who studied them.

A study published Thursday in the journal Current Biology said there are no more than 800 of the primates, which researchers named Pongo tapanuliensis, making it the most endangered great ape species.

The researchers say the population is highly vulnerable and its habitat is facing further pressure from development.

“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,” they said.

It’s the first great ape species to be proposed by scientists in nearly 90 years. Previously, science has recognized six great ape species: Sumatran and Bornean orangutans, eastern and western gorillas, chimpanzees and bonobos.

The research is based on analysis of the skeleton of an adult male killed in a conflict with villagers, a genetic study indicating the population’s evolutionary split from other orangutans occurred about 3.4 million years ago, and analysis since 2006 of behavioral and habitat differences.

The primates are confined to a range of about 425 square miles in the Batang Toru forest in the Tapanuli districts of Northern Sumatra. Historically, the population has probably been isolated from Sumatran orangutans further north for 10,000 to 20,000 years.