 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.