Oryzomys ratticeps (Hensel, 1873) . Abh. König Akad. Wiss. Berlin, 1872:36 [1873].

TYPE LOCALITY: Brazil, Rio Grande do Sul .

DISTRIBUTION: E Brazil, NE Argentina, and Paraguay.

SYNONYMS: moojeni, paraganus, rex (of Winge, 1887), tropicius.

COMMENTS: Referred to O. buccinatus by Hershkovitz (1959a) but its separate specific status is well-established (Avila-Pires, 1960a; Moojen, 1952).