Oryzomys nelsoni is an extinct rodent of María Madre Island, Nayarit, Mexico. Within the genus Oryzomys of the family Cricetidae, it may have been most closely related to the mainland species O. albiventer. Since its first description in 1898, most authors have regarded it as a distinct species, but it has also been classified as a mere subspecies of the marsh rice rat (O. palustris).
Oryzomys couesi, also known as Coues's rice rat, is a semiaquatic rodent in the family Cricetidae occurring from southernmost Texas through Mexico and Central America into northwestern Colombia. It is usually found in wet habitats, such as marshes, but also lives in drier forests and shrublands. Weighing about 43 to 82 g, O. couesi is a medium-sized to large rat. The coarse fur is buff to reddish above and white to buff below. The hindfeet show some specializations for life in the water, such as reduced ungual tufts of hair around the digits. It has 56 chromosomes. There is much geographic variation in size, proportions, color, and skull features. Oryzomys couesi is active during the night and builds nests of vegetation that are suspended among reeds about 1 m (3.3 ft) above the ground. It is an excellent swimmer and dives well, but can also climb in vegetation. An omnivore, it eats both plant and animal food, including seeds and insects. It breeds throughout the year; females give birth to about four young after a pregnancy of 21 to 28 days. The species may be infected by several different parasites and by two hantaviruses.
Oryzomys is a genus of semiaquatic rodents in the tribe Oryzomyini living in southern North America and far northern South America. It includes eight species, two of which—the marsh rice rat (O. palustris) of the United States and O. couesi of Mexico and Central America—are widespread; the six others have more restricted distributions. The species have had eventful taxonomic histories, and most species were at one time included in the marsh rice rat; additional species may be recognized in the future. The name Oryzomys was established in 1857 by Spencer Fullerton Baird for the marsh rice rat and was soon applied to over a hundred species of American rodents. Subsequently, the genus gradually became more narrowly defined until its current contents were established in 2006, when ten new genera were established for species previously placed in Oryzomys.
Transandinomys bolivaris, also known as the long-whiskered rice rat, is a rodent in the family Cricetidae. It is found in humid forest from northeastern Honduras to western Ecuador, up to 1,800 m (5,900 ft) above sea level. Since it was first described in 1901 from Ecuador, six scientific names have been introduced for it, but their common identity was not documented until 1998 and the species has long been known under the name Oryzomys bombycinus, described from Panama in 1912. The name Oryzomys bolivaris was used before it was moved to the new genus Transandinomys with Transandinomys talamancae in 2006.
Oryzomys dimidiatus, also known as the Nicaraguan oryzomys, Thomas's rice rat, or the Nicaraguan rice rat, is a rodent in the family Cricetidae. It is known from only three specimens, all collected in southeastern Nicaragua since 1904. Placed in Nectomys upon its discovery, it was later classified in its own subgenus of Oryzomys and finally recognized as closely related to other species now placed in Oryzomys, including the marsh rice rat and Coues' rice rat, which occurs in the same region.
Oryzomys gorgasi, also known as Gorgas's oryzomys or Gorgas's rice rat, is a rodent in the genus Oryzomys of family Cricetidae. First recorded in 1967, it is known from only a few localities, including a freshwater swamp in the lowlands of northwestern Colombia and a mangrove islet in northwestern Venezuela. It reportedly formerly occurred on the island of Curaçao off northwestern Venezuela; this extinct population has been described as a separate species, Oryzomys curasoae, but does not differ morphologically from mainland populations.
The marsh rice rat is a semiaquatic North American rodent in the family Cricetidae. It usually occurs in wetland habitats, such as swamps and salt marshes. It is found mostly in the eastern and southern United States, from New Jersey and Kansas south to Florida and northeasternmost Tamaulipas, Mexico; its range previously extended further west and north, where it may have been a commensal in corn-cultivating communities. Weighing about 40 to 80 g, the marsh rice rat is a medium-sized rodent that resembles the common black and brown rat. The upperparts are generally gray-brown, but are reddish in many Florida populations. The feet show several specializations for life in the water. The skull is large and flattened, and is short at the front.
Oryzomys albiventer is a rodent in the genus Oryzomys of family Cricetidae from interior western Mexico, in the states of Jalisco, Guanajuato, and Michoacán. First described in 1901 as a separate species, it was later lumped under O. couesi and the marsh rice rat (O. palustris) until it was reinstated as a species in 2009. 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. Its range has been much impacted by agricultural development, but isolated populations are thought to persist.
Gigantolaelaps is a genus of mites in the family Laelapidae. It is found in the fur of cricetid rodents, most often from the tribe Oryzomyini, from South America north to the southern United States. They are large (>1 mm) and darkly colored and have a complex life cycle.
Gigantolaelaps mattogrossensis is a mite from the Americas. It has been found on the marsh rice rat, hispid cotton rat, black rat, brown rat, and white-footed mouse in the United States. In Venezuela, it has been recorded from Holochilus brasiliensis, Sigmodon hirsutus, and Marmosa robinsoni. In Argentina, it has been found on Scapteromys aquaticus, Oligoryzomys flavescens, and Holochilus brasiliensis. The North American form was first described as a separate species, Gigantolaelaps cricetidarum, and is still occasionally considered as such.
Androlaelaps fahrenholzi is a species of mite in the genus Androlaelaps of the family Laelapidae. It occurs throughout the contiguous United States, where it has been recorded on the following mammals:
Haemogamasus is a genus of mites in the family Haemogamasidae. In North America, they mostly infect rodents, in addition to other small mammals such as shrews, talpids, and Virginia opossums.
Laelaps manguinhosi is a species of parasitic mite in the family Laelapidae. In the United States, it has been found on the marsh rice rat in Florida, Texas, and South Carolina. Other recorded hosts include the sigmodontine rodents Scapteromys aquaticus, Akodon azarae, Oligoryzomys flavescens, and Holochilus brasiliensis in Argentina and Oryzomys couesi and Handleyomys melanotis in Mexico. In Venezuela, it mainly infects the oryzomyines Holochilus sciureus and Nectomys, but it has also been recorded on a variety of other mammals and even on a bird. A separate subspecies, Laelaps manguinhosi calvescens, has been described from the ichthyomyine rodent Neusticomys venezuelae.
Listrophorus is a genus of parasitic mites in the family Listrophoridae. North American species with their hosts include:
Listrophoridae is a family of mites in the suborder Psoroptidia of the order Sarcoptiformes. The family contains small, long mites specialized for grasping the hairs of mammals. North American genera include:
Prolistrophorus bakeri is a parasitic mite in the genus Prolistrophorus. Together with the Argentine P. hirstianus, it forms the subgenus Beprolistrophorus. P. bakeri has been found on the hispid cotton rat, marsh rice rat, and cotton mouse in Georgia, South Carolina, Texas, and Florida and on Oryzomys couesi in Colima. It was formerly placed in the genus Listrophorus.
Prolistrophorus grassii is a parasitic mite in the genus Prolistrophorus. It was described as Listrophorus grassii in 1954 from the marsh rice rat in Georgia. In 1974, Fain and Hyland placed it in Prolistrophorus and in 1984, Fain and Lukoschus redescribed the species on the basis of collections from the marsh rice rat in Georgia, Alabama, and Florida and the southern bog lemming in Indiana, West Virginia, and Iowa.
Radfordia palustris is a species of mite in the subgenus Hesperomyobia of the genus Radfordia. It has been recorded on the marsh rice rat in Florida, Georgia, and South Carolina.
Laelaps is a genus of common parasitic mites in the family Laelapidae. Species, with their hosts, include:
