Sigmodon (Sigmodon) ochrognathus Bailey 1902

Sigmodon (Sigmodon) ochrognathus Bailey 1902, Proc. Biol. Soc. Wash., 15: 115.

Type Locality: USA, Texas, Brewster Co., Chisos Mountains, 8000 ft (2438 m).

Vernacular Names: Yellow-nosed Cotton Rat.

Synonyms: Sigmodon (Sigmodon) baileyi J. A. Allen 1903; Sigmodon (Sigmodon) madrensis Goldman and M. C. Gardner 1947; Sigmodon (Sigmodon) montanus Benson 1940 .

Distribution: SE Arizona, extreme SW New Mexico, and Transpecos, Texas, USA, south to C Durango, México; northern outlier population may persist in Guadalupe Mtns, Transpecos, Texas (see Stangl and Dalquest, 1991).

Conservation: IUCN – Lower Risk (lc).

Discussion: Subgenus Sigmodon, S. hispidus species group. Basal clade within the S. hispidus assemblage according to phylogenetic interpretations of cytochrome b data (Peppers et al., 2002), not with S. fulviventer and kin (Baker, 1969). Findley and Jones (1960) detected no consistent pattern of size and pelage color variation to justify recognition of subspecies, a conclusion sustained by the low genetic distances recorded among populations (Carroll et al., 2002). See Baker and Shump (1978, Mammalian Species, 97).