distinctive in the well-developed ridges along the margins of the interorbital region, the short interparietal bone (part of the roof of the braincase), and the long nasal bones. In 1937, Bole described another species of Panamanian Oryzomys, Oryzomys azuerensis from Paracoté, Veraguas Province. It is a brown form, lacking the reddish tones of nearby populations, and has a broad skull with a short rostrum (front part) and ridges on the interorbital region like those of gatunensis. Although Goldman recommended to him that gatunensis and azuerensis both be treated as subspecies of couesi, Bole described azuerensis as a species because it did not seem intermediate between the geographically closest forms, gatunensis and couesi, and was separated by a large gap from the nearest known populations of O. couesi in northwestern Costa Rica and southeastern Nicaragua. In a 1966 review of Panamanian mammals, Charles Handley reduced both gatunensis and azuerensis to subspecies of the marsh rice rat (in which O. couesi was included at the time), and when O. couesi was reinstated as a separate species these forms went with it. Specimens from near the type locality of azuerensis differ by about 7% in their Cytb sequences from other O. couesi, which suggests that they may represent a separate species. However, Hanson and colleagues did not reinstate azuerensis as a species, because they could not examine samples of gatunensis. Oryzomys couesi was first reported from Colombia in 1987, when Philip Hershkovitz reported on its occurrence at Montería in Córdoba Department, northwestern Colombia. The Colombian specimen is ochraceous in color throughout and according to Hershkovitz almost identical to specimens from Guatemala, but distinctive in that the upper lip is white. He suggested that O. couesi may also be discovered in the Pacific lowlands of the Chocó in western Colombia. Common names Several common names have been proposed for Oryzomys couesi and the synonyms currently associated with it. Eliot in 1905 and Goldman in 1918 gave separate common names for each of the species and subspecies they recognized. Many authors have used "Coues' Rice Rat" or some variation thereof for O. couesi, but "Coues' Oryzomys" has also been used. Description Oryzomys couesi is a medium-sized to large rat with coarse fur that is buff to reddish above, becoming paler towards the sides and cheeks and darker on the rump and face. The underparts are white to buff. The fur is shorter, brighter, and more