RELATIONSHIPS OF THE ENDANGERED MEXICAN KIT FOX (VULPES MACROTIS ZINSERI) TO NORTH-AMERICAN ARID-LAND FOXES BASED ON MITOCHONDRIAL-DNA SEQUENCE DATA

The Mexican kit fox (Vulpes macrotis zinseri) is an endangered subspec ies that is restricted to the arid plains of the Sierra Madre Mountain s of Mexico. Previous genetic analysis of other arid-land fox populati ons in the U.S. showed that the species is divided into two phylogenet ically distinct taxa; the kit fox occupies the western, and the swift fox, the eastern plains bordering the Rocky Mountains. We analyzed 740 base pairs (bp) of cytochrome b sequence and 350 bp of control region sequence to determine if Mexican kit foxes are genetically distinct a nd to assess their relationship to kit and swift foxes of the U.S. We found two genotypes in 19 foxes from Nuevo Leon and Coahuila, Mexico t hat differed by a single base pair substitution. These genotypes were phylogenetically grouped with those sequences from kit foxes in Arizon a, Utah, and New Mexico but differed from them by 1 to 4 substitutions (0.3 to 1.3%) in control region sequence. Our results suggest that th e Mexican kit foxes are closely associated with populations of the kit fox to the west of the Rocky Mountains and, although they have unique genotypes, Mexican kit foxes have only recently been isolated from th eir conspecifics in the U.S.