Mechuka giant flying squirrel
The Mechuka giant flying squirrel ("Petaurista mechukaensis") is a species of rodent in the family Sciuridae. First described in 2007 from East Himalayan forests at altitudes of in the region of Mechuka of north-central Arunachal Pradesh in India, its taxonomic status and position is not fully resolved. it was originally described as "P. nigra" but has been replaced by "mechukaensis" because it was a primary homonym of "P. nigra" Wang 1981. Taxonomy and appearance. In 2016, it was proposed that "mechukaensis" is the same species as the taxon "nigra", which was described in 1981 from  northwestern Yunnan in China and traditionally has been considered a part of the Indian or red giant flying squirrel. If confirmed and recognized as a distinct species, this means that the correct scientific name for the Mechuka giant flying squirrel is "Petaurista nigra". In a genetic study published in 2006, "nigra" (initially misidentified as "yunanensis") was found to be closely related to "albiventer". The position of "albiventer" is itself disputed; although traditionally considered a subspecies of the red giant flying squirrel, strong evidence points to it being a separate species, which has been followed by several recent authorities. Based on  genetic evidence, "nigra" can be considered a subspecies of "P. albiventer" or a closely related separate species. In 2017, a new subspecies "muzongensis" that is closely associated with "nigra" was described from southeastern Xizang, China, quite near to the border with Arunachal Pradesh, India. These two and "mechukaensis" have ochraceous–buff or orange–buff underparts, becoming deep rufous–chestnut towards the edge of the patagium. The head and upperparts are dark chestnut, darker towards the upper back and head, and the tail is blackish. The taxon "nigra" can be distinguished by the scattered creamy–white guard hairs on its mid  to lower back (largely absent from head and shoulder region), resulting in this region having an overall dark but grizzled appearance unlike "muzongensis" and "mechukaensis". The taxa "muzongensis" and "mechukaensis", which were described close to each other but on separate sides of the China–India border, are extremely similar (if not identical). Based on a small number of specimens, "nigra", "muzongensis" and "mechukaensis" are relatively large, with measurements in the upper range of that reported for the red giant flying squirrel.