'Vulpes macrotis arsipus' has long been recognized as the desert kit fox sub-species - but in the new account in the updated Third Edition of 'Mammal Species of the World' published late in 2005: Wilson, D. E., and D. M. Reeder (eds). 2005. Mammal Species of the World. Johns Hopkins University Press, 2,142 pp. (available from Johns Hopkins University Press, http://www.press.jhu.edu), there are only two recognized sub-species of the kit fox, Vulpes macrotis mutica (San Joaquin kit fox) and Vulpes macrotis macrotis (all other kit foxes).