Highland Small Rice Rat

The Páramo colilargo has a greyish head, buffish upper parts and greyish-buff underparts and there is a clear demarcation between the dorsal and ventral colouring. The tail is dark above and pale below and is usually shorter than 110 mm (4.3 in). The feet have whitish hairs on the upper surface, and the metatarsal pads on the soles are narrow. Compared to the closely related Microryzomys minutus, the skull is wider and more robust, with longer incisive foramina and with longer rows of teeth. The diploid chromosomal count is 2n=57 and FN=58.

This rodent is native to South America where it occurs in the high Andes of Ecuador, Peru and Bolivia. Its altitudinal range is between 2,500 and 4,000 m (8,200 and 13,100 ft). Its range includes the Cordillera Central in Colombia where there is a separate population, and extends through the Cordillera Occidental and Cordillera Oriental of Ecuador, to the Andes of northern Peru, as far south as Junin. Its typical habitat is moist subalpine forest and páramo, a high altitude grassland.