Sigmodon (Sigmodon) planifrons Nelson and Goldman 1933

Sigmodon (Sigmodon) planifrons Nelson and Goldman 1933, Proc. Biol. Soc. Wash., 46: 197.

Type Locality: México, Oaxaca State, Juquila, 5000 ft (1524 m).

Vernacular Names: Miahuatlan Cotton Rat.

Synonyms: Sigmodon (Sigmodon) minor Goodwin 1955; Sigmodon (Sigmodon) setzeri Goodwin 1959 .

Distribution: As so far known, limited to Sierra de Miahuatlán, S Oaxaca, México.

Discussion: Subgenus Sigmodon ( S. hispidus species group?). Described as a species but relegated to a subspecies of S. alleni by Baker (1969). As noted by Nelson and Goldman (1933 b), the diminutive size exhibited by the type series, as well as the material and sympatry later reported by Goodwin (1955 b, 1969), suggests that the form is distinct from S. alleni; renewed study of the Oaxacan taxa named by Goodwin (1955 b) will prove critical to much-needed revision of the S. alleni complex (see discussion in Carleton et al., 1999).