The Baja pocket mouse has six recognised subspecies.[3] The Montserrat Island pocket mouse (Chaetodipus rudinoris fornicatus) became extinct in 1975 (last sighting).[1][4]
Chaetodipus rudinoris rudinoris
Chaetodipus rudinoris extimus
†Chaetodipus rudinoris fornicatus (Monserrat Island pocket mouse)
^Álvarez-Castañeda, S. T. and Cortés-Calva, P. 2002. Extirpation of Bailey's pocket mouse Chaetodipus baileyi fornicatus (Heteromyidae : Mammalia), from Isla Montserrat, Baja California Sur, Mexico. Western North American Naturalist 62: 496-497.