Oryzomys alfaroi (J. A. Allen, 1891) . Bull. Am. Mus. Nat. Hist., 3:214.

TYPE LOCALITY: Costa Rica, Alajuela Prov., San Carlos .

DISTRIBUTION: Lowland to lower montane forests from S Tamaulipas and Oaxaca, Mexico, through Middle America, to W Colombia and Ecuador.

SYNONYMS: agrestis, dariensis, gloriaensis, gracilis, incertus (of J. A. Allen, 1908), intagensis, palatinus, palmirae.

COMMENTS: Goldman (1918) forged a broad definition of the species, expanded more so by Hall and Kelson (1959), which encompassed many forms previously treated as distinct (e.g., Merriam, 1901). We recognize chapmani, rhabdops, and saturatior as species (revision in progress). Oryzomys alfaroi proper may be more closely related to melanotis-rostratus than to the chapmani-saturatior group. Karyotype reported by Haiduk et al. (1979) and Engstrom (1984).