The third species of the most mysterious and rarest amongst all flying squirrels has been discovered in China's Yunnan Province.
The species that belong to genus Biswamoyopterus, comprised two large (1.4-1.8 kg) species endemic to southern Asia: the Namdapha flying squirrel (India) and the Laotian giant flying squirrel (Lao PDR).
Each is only known from a single specimen discovered in 1981 and 2013, respectively, according to the study published in the journal of ZooKeys.
In 2018, a specimen identifiable as Biswamoyopterus was unexpectedly found in the collections of the Kunming Institute of Zoology (KIZ), Chinese Academy of Sciences by in-house expert Quan Li. It had been collected from Mount Gaoligong in Yunnan Province, Southwest China.
Initially, the individual was considered to belong to the "missing" Namdapha flying squirrel: a species considered as critically endangered due to hunting and habitat loss. However, a closer look at the specimen from KIZ made it clear that the squirrel exhibited a colouration, as well as skull and teeth anatomy, distinct from any of the previously known species in the genus.
After the survey, the researchers successfully obtained another specimen and, additionally, recorded observations of two other flying squirrels. As a result, they included a third member to the enigmatic genus: Biswamoyopterus gaoligongensis, also referred to as the Mount Gaoligong flying squirrel.
"The morphological features of B. gaoligongensis are closer to the critically endangered and missing Namdapha flying squirrel, but is still readily identifiable as a distinct species," explained the lead author, Quan Li.
"The new species was discovered in the ''blank area'' spanning 1,250 km between the isolated habitats of the two known species, which suggests that the genus is much more widespread than previously thought. There is still hope for new Biswamoyopterus populations to be discovered in between or right next to the already known localities," he said.
As for the conservation status of the newly described species, the researchers note that it inhabits low-altitude forests which are in close proximity to nearby human settlements. Thereby, they are vulnerable to anthropogenic threats, such as agricultural reclamation and poaching.
"Therefore, there is an urgent need to study the ecology, distribution, and conservation status of this rare and very beautiful genus," concluded the lead author.