Peromyscus nasutus J. A. Allen 1891

Peromyscus nasutus J. A. Allen 1891, Bull. Am. Mus . Nat. Hist., 3: 229.

Type Locality: USA, Colorado, Larimer Co., Estes Park.

Vernacular Names: Northern Rock Deermouse.

Synonyms: Peromyscus griseus Benson 1932; Peromyscus penicillatus Mearns 1896 .

Distribution: C Colorado and SE Utah, south through New Mexico and Trans-Pecos Texas, USA, to NW Coahuila, México.

Conservation: IUCN – Lower Risk (lc).

Discussion: P. truei species group. Considered a distinct species (Osgood, 1909) until synonymized under P. difficilis by Hoffmeister and de la Torre (1961). Separated as a sibling species of P. difficilis by Zimmerman et al. (1975, 1978), as also recognized by Carleton (1989); however, the weak genic divergence persuaded Janecek (1990) to retain nasutus within P. difficilis . DeWalt et al. (1993 b) also uncovered low levels of genetic divergence among attwateri, difficilis, and nasutus (e.g., less than P. gratus versus P. truei) but retained them as species, as did Tiemann-Boege et al. (2000) based on a broader survey of cytochrome b sequences among members of the boylii and truei species groups. Also see remarks under P. difficilis . Includes penicillatus, which Osgood (1909) had misclassified under P. boylii (see Diersing, 1976); distributional records in the Davis Mtns, W Texas, reviewed by Bradley et al. (1999 b).