Date of this Version
Journal of Mammalogy (November 1971) 52(4).
The species Oryzomys dimidiatus was originally named and described by Thomas (Annals of the Museum of Natural History, series 7, 15: 584-591, 1905) as a member of the genus Nectomys on the basis of a single specimen from the Rio Escondido, 7 miles below Rama, Nicaragua (approximately 1 km. S and 8½ km. E Ranla, 20 m, Zelaya), obtained by W. G. Palmer on November 5, 1904. Although there has been speculation on the relationships of this taxon (currently regarded as the only member of the subgenus Micronectmays, genus Oryzomys--see Hershkovitz, Journal of Mammalogy, 51: 789-794, 1970, for review), the holotype has remained the only known specimen.
A second individual (University of Kansas Museum of Natural History, no. 106607) assignable to this species was taken on July 26, 1966 by R. W. Turner at El Recreo, 25 m, Zelaya, Nicaragua, approximately 15 kilometers to the west of the type locality. This rat, a young adult male, was trapped in a stand of cane, 8 to 10 feet tall, along the south bank of the Rio Mico. The cane was nearly impenetrable excepting for two paths through it to the river, and it was along these paths that traps were set, baited with rolled oats. In addition to O . dimidiatus, other small mammals taken at this place included Oryzomys caliginosus, O. fulvescens, O. palustris, Sigmodon hispidus, and one Sylvilagus brasiliensis that was shot along the edge of the cane.