A small deermouse from Coronados Island in the Gulf of California, Mexico. Its back is dark with a cinnamon wash, its underside is white, and its long tail is sparsely furred.
The upperparts are plumbeous-black with a cinnamon wash, and the underparts are white. The tail is long and sparsely haired, with a faint two-tone boundary over roughly the basal two-thirds.
In a 1994 survey on Coronados Island, 20 mice were captured in one night, mostly on the sand spit and a few among rocks. A later island survey commonly captured them in rocky areas, stony ground and canyons, less often on scrub and salt-tolerant plains, and none in coastal dunes.
An extinction-risk assessment has not been added yet.