Flying squirrels can be found in most of Earth’s forests, but you probably wouldn’t be able to actually find one—the elusive little mammals are so good at flying under the radar that scientists have a hard time studying them.

That’s why, when Quan Li of the Kunming Institute of Zoology at the Chinese Academy of Sciences spotted a strange-looking squirrel specimen in the institute’s collection last year, he thought it was just a variation of the rare Namdapha flying squirrel, a species in the Biswamoyopterus genus. Upon further investigation, Smithsonian.com reports, he realized the differences were considerable enough that it must be a previously unknown species within the same genus.

The new species (called Biswamoyopterus gaoligongensis, or the Mount Gaoligong flying squirrel, after the region where it was first discovered) has bi-colored ear tufts, a dark brown scrotum, a white belly, and a shorter, wider skull than other close relatives. Like its relatives, the new guy weighs between 3 and 4 pounds, or about the size of a Chihuahua.

Kadoorie Farm & Botanic Garden

Part of the reason that Quan Li first misidentified the squirrel he saw as a Namdapha squirrel is because we don’t know that much about Namdapha squirrels—scientists have only ever spotted one of them, in 1981. It’s critically endangered due to hunting and habitat loss.

To study the new flying squirrel species further, Quan Li and his colleagues traveled to Mount Gaoligong in Yunnan Province in southwest China, where the specimen had been collected before being brought to the institute. There, they were able to obtain another Mount Gaoligong flying squirrel specimen, as well as observe two others.

The area in which the new species was found is within the 777-mile-long region between where the Namdapha squirrel was first observed in 1981 in India, and where a specimen from the Laotian giant flying squirrel (the other known species in the Biswamoyopterus genus) was observed in 2013. This “suggests that the genus is much more widespread than we previously thought,” Quan Li said in a statement announcing the finding.

Quan Li and his team are hoping to discover more squirrels in the area, and soon. Because these squirrels inhabit low-altitude forests near human settlements, they’re extra-susceptible to poaching or habitat destruction.

[h/t Smithsonian.com]