Peromyscus madrensis Merriam, 1898 . Proc. Biol. Soc. Washington, 12:16.

TYPE LOCALITY: Mexico, Nayarit, Très Marfas Islands, Marfa Madre Island .

DISTRIBUTION: Très Marfas Islands, Mexico.

COMMENTS: Treated as a subspecies of P. boylii by Osgood (1909) but considered distinct by Carleton (1977); viewed as closely related to P. simulus by Carleton et al. (1982). Perhaps extirpated on Marfa Magdalena Island, where Rattus rattus is now abundant (Carleton et al., 1982; Wilson, 1991). P. boylii species group.