Akodon spegazzinii Thomas, 1897 . Ann. Mag. Nat. Hist., ser. 6, 20:216.

TYPE LOCALITY: Argentina, Salta Prov., lower Rio Cachi .

DISTRIBUTION: E Andean slopes, 400 to 1000 m, of NW Argentina.

SYNONYMS: alterus, tucumanensis.

COMMENTS: Subgenus Akodon . Karyology and morphometries reviewed, as A. boliviensis tucumanensis, by Barquez et al. (1980). Myers et al. (1990) segregated spegazzinii, with tucumanensis as a subspecies, as a species distinct from A. boliviensis . Significance of marginal genetic and morphologic divergence of alterus evaluated by Blaustein et al. (1992).