Vulpes qiuzhudingi is believed to be the ancestor of which small fox native to the Northern Hemisphere?
Vulpes qiuzhudingi:  The species is believed to be the ancestor of "Vulpes lagopus", the modern Arctic fox, which would support the "Out of Tibet" theory: namely, that a number of current arctic species trace their ancestry to species originally from the Tibetan Plateau. Arctic fox: The Arctic fox ("Vulpes lagopus"), also known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Arctic tundra biome.
Arctic fox