Sigmodontomys alfari J. A. Allen, 1897 . Bull. Am. Mus. Nat. Hist., 9:39.

TYPE LOCALITY: Costa Rica, Limón Prov., Jimenez, 700 ft .

DISTRIBUTION: Lowland forest from E Honduras to Panama; C and W Colombia to NW Venezuela and NW Ecuador.

SYNONYMS: barbacoas, efficax, esmeraldarum, ochraceus, ochrinus, russulus.

COMMENTS: Karyotype reported by Gardner and Patton (1976).