Calomys callidus (Thomas, 1916) . Ann. Mag. Nat. Hist., ser. 8, 17:182.

TYPE LOCALITY: Argentina, Corrientes Prov., Goya, 600 ft .

DISTRIBUTION: EC Argentina and E Paraguay.

COMMENTS: Diagnosed as a subspecies of C. venustus and recognized as such (e.g., Cabrera, 1961) until Hershkovitz (1962) placed it in synonymy with C. callosus callosus . Specific status of callidus affirmed by Corti et al. (1987), who summarized its distribution and karyotypic discrimination.