Calomys callosus (Rengger, 1830) . Naturg. Saugeth. Paraguay, p. 231.

TYPE LOCALITY: Paraguay, Villa Pilar Dept., Rio Paraguay, opposite mouth of Rio Bermejo .

DISTRIBUTION: E. and S. W. Brazil; Bolivia; Paraguay; N. Argentina.

COMMENT: Includes venustus and expulsus; see Hershkovitz, 1962, Fieldiana Zool., 46:171- 174. Formerly included fecundus (see Pearson and Patton, 1976, J. Mammal., 57:343) and muriculus (see Williams and Mares, 1978, Ann. Carnegie Mus., 47(9): 197, 200, 214). AL included muriculus in callosus .

ISIS NUMBER: 5301410008006001001 as C. callosus .

5301410008006003001 as C. expulsus.

5301410008006010001 as C. venustus.