Tres Marias Deer Mouse

Peromyscus madrensis Merriam

Peromyscus madrensis Merriam, 1898a:16.—Carleton, 1977:41.

Peromyscus boylei madrensis.—Osgood, 1909:152.

Peromyscus boylii madrensis.—Miller and Kellogg, 1955:495.—Hall and Kelson, 1959:635.

HOLOTYPE.—USNM 89223, adult male, skin and skull from Maria Madre Island, Tres Marias Islands, Nayarit. Holotype examined.

GENERAL DISTRIBUTION.—Confined to the Tres Marias Islands, about 50 miles off the coast of Nayarit.

DISTRIBUTION IN NAYARIT.—Maria Madre Island, Maria Magdalena Island, Maria Cleofas Island, and San Juanito Island.

DIAGNOSIS.—A species of the Peromyscus boylii species group, subgenus Peromyscus, distinguished by its large skull and relatively small toothrow and auditory bullae; dentition relatively simple; tail long, indistinctly bicolored, and with terminal one-third as dark below as above; hind feet large (24–28 mm) and pinnae relatively small (17–20 mm); phallus comparatively small with dorsal lappets weakly developed and no ventral lappet; karyotype with four pairs of biarmed autosomes (2n=48; FN=54).

TAXONOMIC