Oryzomys chapmani Thomas, 1898 . Ann. Mag. Nat. Hist., ser. 7, 1:179.

TYPE LOCALITY: Mexico, Veracruz, Jalapa, 4400 ft .

DISTRIBUTION: Cloud forest elevations of Cordillera Oriental (Tamaulipas to Veracruz), Sistema Montanosa (N Oaxaca), and Sierra Madre del Sur (S Oaxaca and Guerrero), Mexico.

SYNONYMS: caudatus, dilutior, guerrerensis, huastecae.

COMMENTS: Relegated to a subspecies of O. alfaroi by Goldman (1918). Goodwin (1969) recognized caudatus as distinct from O. alfaroi in N Oaxaca, but, as earlier arranged by Merriam (1901), O. chapmani has priority for this Mexican species. We view O. saturatior as the vicariant relative of O. chapmani (revision in progress). Karyotype reported, as O. caudatus, by Haiduk et al. (1979).