Temporal range: Rancholabrean (300,000 years before present) – present
Marsh rice rat (Oryzomys palustris)
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Phylum:
Chordata
Class:
Mammalia
Order:
Rodentia
Family:
Cricetidae
Subfamily:
Sigmodontinae
Tribe:
Oryzomyini
Genus:
Oryzomys Baird, 1857
Type species
Mus palustris
Harlan, 1837
Species[1]
Oryzomys albiventer
Oryzomys couesi
Oryzomys dimidiatus
Oryzomys gorgasi
Oryzomys palustris
Oryzomys peninsulae
†Oryzomys antillarum
†Oryzomys nelsoni
Distribution of Oryzomys: dark blue, marsh rice rat (O. palustris); light blue, former distribution of the marsh rice rat; red, O. couesi; pink, O. albiventer; dark green, O. peninsulae; orange, O. nelsoni; light green, O. antillarum; yellow, O. dimidiatus and O. couesi; brown, O. gorgasi.
Synonyms[1]
Hesperomys (Oryzomys) Baird, 1857[2][Note 1]
Oryzomys: Allen, 1890[3][Note 2]
Micronectomys Hershkovitz, 1948[7][Note 3]
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.
Species of Oryzomys are medium-sized rats with long, coarse fur. The upperparts are gray to reddish and the underparts white to buff. The animals have broad feet with reduced or absent ungual tufts of hair around the claws and, in at least some species, with webbing between the toes. The rostrum (front part of the skull) is broad and the braincase is high. Both the marsh rice rat and O. couesi have 56 chromosomes, lack a gall bladder, and have a complex penis (as is characteristic of the Sigmodontinae) with some traits that are rare among oryzomyines; these characteristics are unknown in the other species of this genus.
The habitat includes various kinds of wetlands, such as lakes, marshes, and rivers. Oryzomys species swim well, are active during the night, and eat both plant and animal food. They build woven nests of vegetation. After a gestation period of 21 to 28 days, about four young are born. Species of Oryzomys are infected by numerous parasites and carry at least three hantaviruses, one of which (Bayou virus) also infects humans. Two, maybe three, species have gone extinct over the last two centuries and at least one other is endangered, but the widespread marsh rice rat and O. couesi are not threatened.
^ abcCite error: The named reference CAC116 was invoked but never defined (see the help page).
^Baird, 1857, p. 482, cf. p. 459
^Allen, 1890, p. 187
^Goldman, 1918, p. 11
^Tate, 1932, p. 4
^Coues, 1890, p. 4164
^Hershovitz, 1948, p. 54
^Cite error: The named reference MC1144 was invoked but never defined (see the help page).
Cite error: There are <ref group=Note> tags on this page, but the references will not show without a {{reflist|group=Note}} template (see the help page).
new genera were established for species previously placed in Oryzomys. Species of Oryzomys are medium-sized rats with long, coarse fur. The upperparts...
some of the peripheral forms of the group, such as Oryzomys antillarum from Jamaica and Oryzomys peninsulae from the Baja California Peninsula, have...
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...
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...
Oryzomys antillarum, also known as the Jamaican rice rat, is an extinct rodent of Jamaica. A member of the genus Oryzomys within the family Cricetidae...
and the molars). Oryzomys peninsulae was first collected in 1896 and Oldfield Thomas described it in 1897 as a full species of Oryzomys. It was retained...
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...
Oryzomys albiventer is a rodent in the genus Oryzomys of family Cricetidae from interior western Mexico, in the states of Jalisco, Guanajuato, and Michoacán...
populations may be recognized as a separate species, Oryzomys texensis. The species is part of the genus Oryzomys, which also includes several others occurring...
Oryzomysia oryzomys is a parasitic mite in the genus Oryzomysia of the family Atopomelidae. It has been found on the marsh rice rat (Oryzomys palustris)...
included in the genus Oryzomys. Its taxonomic history has been complex, with the names Oryzomys angouya, Oryzomys buccinatus, and Oryzomys ratticeps in use...
described Oryzomys wavrini as a new species of Oryzomys from Paraguay. In the next decades, it was viewed as an aberrant species of Oryzomys (then used...
rat or Ecuadorian oryzomys (in various spellings) can refer to two species of rice rats: Nephelomys auriventer, Golden-bellied oryzomys Oreoryzomys balneator...
lumped under "Oryzomys capito" (now classified in the genera Hylaeamys, Euryoryzomys, and Transandinomys). They described the new species Oryzomys emmonsae...
times. Until 2006, it was classified in the genus Oryzomys as Oryzomys laticeps. The species Oryzomys seuanezi is now a junior synonym of H. laticeps....
Honduras, Mexico, Nicaragua, and Panama. It was previously included in Oryzomys as Oryzomys alfaroi. Its natural habitats are subtropical and tropical lowland...
allocation of synonyms dates from 1998. It was placed in the genus Oryzomys until 2006, as Oryzomys talamancae, but is not closely related to the type species...
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...
(currently Oligoryzomys longicaudatus). By 1894, it was placed in Oryzomys, as Oryzomys albigularis, and associated with what is now Nephelomys meridensis...
Cricetidae. It is found only in Mexico. It was previously placed in Oryzomys as Oryzomys chapmani, but has been provisionally transferred to the genus Handleyomys...
lowland tropical rainforest. It was formerly placed in the genus Oryzomys, as Oryzomys macconnelli, but in 2006 it was reclassified as the type species...
originally placed in Oryzomys and named Oryzomys polius. In 2006, a cladistic analysis found that it was not closely related to Oryzomys in the strict sense...
known as the elegant oryzomys or elegant rice rat, is a rodent species in the family Cricetidae. Previously it was known as Oryzomys nitidus, but it is...
Hylaeamys megacephalus, also known as Azara's broad-headed oryzomys or the large-headed rice rat, is a species of rodent in the genus Hylaeamys of family...
A variety of parasites have been recorded from the marsh rice rat (Oryzomys palustris), a semiaquatic rodent found in the eastern and southern United States...
Calomys species in Oryzomys, conforming to the more conventional taxonomic arrangement; after that, the species was referred to as Oryzomys anoblepas. Over...
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