The Gobi Desert's own Wikipedia entry states that some geographers and ecologists treat its western area as a separate desert, the Taklamakan, rather than as part of the Gobi itself.
What would resolve this A geomorphological and ecological survey establishing where the Taklamakan's dune sea and dry climate genuinely diverge from the Gobi's cold steppe-desert character, agreed on by the physical geography community.
OpenPhysical geographyGobi Desert (Wikipedia)