Marsh Rice Rat - Taxonomy

Taxonomy

The marsh rice rat is classified as one of eight species in the genus Oryzomys, which is distributed from the eastern United States (marsh rice rat) into northwestern South America (O. gorgasi). Oryzomys previously included many other species, which were reclassified in various studies culminating in contributions by Marcelo Weksler and coworkers in 2006 that removed more than forty species from the genus. All are placed in the tribe Oryzomyini ("rice rats"), a diverse assemblage of over a hundred species, and on higher taxonomic levels in the subfamily Sigmodontinae of the family Cricetidae, along with hundreds of other species of mainly small rodents, most of which occur in South and Central America. In the United States, the marsh rice rat is the only oryzomyine rodent except for Oryzomys couesi in a small area of southern Texas; the only other sigmodontines present are several species of cotton rats (Sigmodon) in the southern half of the country.