Oryzomys albiventer
It differs from neighboring Oryzomys populations in size and measurements and is a large, brightly colored species with a long tail and robust skull and molars.Hall argued that O. couesi was the same species as the marsh rice rat (O. palustris) of the United States, and listed albiventer as a subspecies of the latter.[14] They confirmed that Eliot's molestus was based on a large example of O. abiventer,[9] but left the status of the three forms Goldman had associated with albiventer—crinitus, aztecus, and regillus—open, noting that there was no convincing evidence that these represented the same species as O. albiventer.[16] O. albiventer is part of the genus Oryzomys, which currently includes about eight species distributed from the eastern United States (O. palustris) into northwestern South America (O. gorgasi).[2] Many aspects of the systematics of the O. couesi section remain unclear and it is likely that the current classification underestimates the true diversity of the group.[24] O. albiventer occurs at about 1,200 to 1,800 m (3,900 to 5,900 ft) elevation in northern Michoacán, southern Guanajuato, and central and eastern Jalisco,[9] mostly in the area around Lake Chapala.