Described in 1981, the genus Biswamoyopterus is regarded as the most mysterious and rarest amongst all flying squirrels. It comprises 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.
Click here for original story, New species of flying squirrel from Southwest China added to the rarest and ‘most wanted’
Source: Phys.org