Onychomys arenicola Mearns, 1896 . Preliminary diagnosis of new mammals from the Mexican border of the U. S., p. 3 (preprint of Proc. U. S. Natl. Mus., 19: 137 - 140).

TYPE LOCALITY: USA, Texas, El Paso Co., 6 mi above El Paso .

DISTRIBUTION: Chihuahuan Desert: SE Arizona, SC New Mexico, and W Texas, USA, south into C Mexico, to Aguascalientes, San Luis Potosi, and W Tamaulipas.

SYNONYMS: canus, surrufus.

COMMENTS: Placed in full synonymy of O. t. torridus by Hollister (1914). Sympatry with O. torridus and karyotypic discrimination reported by Hinesley (1979), who raised O. arenicola to species—also see Baker et al. (1979). Sullivan et al. (1986) and Riddle and Honneycutt (1990) viewed O. leucogaster and O. arenicola as sister taxa. Specimenbased documentation of geographic range and synonymy of species-group taxa provisionally associated here under O. arenicola highly welcomed.