Oligoryzomys is a genus of rodents in the tribe Oryzomyini of family Cricetidae. Many species are known as pygmy rice rats or colilargos. The genus is found from Mexico to Tierra del Fuego and includes approximately 17 species.
The genus Neacomys, also known as bristly mice because of their spiny fur, includes several species of rodents in the tribe Oryzomyini of family Cricetidae. It is most closely related to Oligoryzomys, Oreoryzomys, and Microryzomys. Neacomys species are mainly found in the Amazon basin, but N. pictus occurs in Panama and N. tenuipes in montane Colombia.
Handleyomys fuscatus, also known as the dusky-footed Handley's mouse or dusky-footed montane mouse, is a species of rodent in the tribe Oryzomyini of family Cricetidae. It was previously placed in the genus Aepeomys, but it is closely similar to Handleyomys intectus, and accordingly both species were placed in the new genus Handleyomys in 2002. It is found only in Colombia.
Microryzomys altissimus, also known as the Páramo colilargo or highland small rice rat, is a species of rodent in the genus Microryzomys of family Cricetidae. It is found in Colombia, Ecuador, and Peru, but the Colombian segment may be a separate species.
Microryzomys minutus, also known as the montane colilargo or the forest small rice rat, is a species of rodent in the genus Microryzomys of family Cricetidae. It is found in Bolivia, Colombia, Ecuador, Peru, and Venezuela, but these populations may represent more than one species.
Nephelomys albigularis, also known as the white-throated oryzomys or Tomes's rice rat, is a species of rodent in the genus Nephelomys of family Cricetidae. Described in 1860, it was the first Nephelomys species to be discovered. It was originally described in the defunct genus Hesperomys as Hesperomys albigularis and considered related to the much smaller H. longicaudatus. By 1894, it was placed in Oryzomys, as Oryzomys albigularis, and associated with what is now Nephelomys meridensis. In the early 1960s, the scope of the species was considerably expanded to include most of the species that are now in Nephelomys, as well as a single name, boliviae, that is currently a synonym of Euryoryzomys nitidus. From 1976 on, several of these were reinstated as separate species.
Oreoryzomys balneator, also known as the Peruvian rice rat or Ecuadoran oryzomys, is a species of rodent in the tribe Oryzomyini of family Cricetidae. It is found in Ecuador and northern Peru in cloud forest at elevations from 1500 to 1800 m. It is the only species in the genus Oreoryzomys, which was included in Oryzomys until 2006. The genus name Oreoryzomys is a combination of ορος the Greek word for "mountain" with the old genus name Oryzomys and refers to the mountainous habitat of O. balneator. Recent research suggests that O. balneator is not closely related to Oryzomys, but instead is probably related to Microryzomys within a clade also including Neacomys and Oligoryzomys.
Mindomys hammondi, also known as Hammond's rice rat or Hammond's oryzomys, is an endangered species of rodent in the tribe Oryzomyini of family Cricetidae. Formerly considered to be related with Nectomys, Sigmodontomys, Megalomys, or Oryzomys, it is now placed in then genus Mindomys, but its relationships remain obscure; some evidence supports a placement near Oecomys or as a basal member of Oryzomyini.
Eremoryzomys polius, also known as the gray rice rat or the Marañon oryzomys, is a rodent species in the tribe Oryzomyini of the family Cricetidae. Discovered in 1912 and first described in 1913 by Wilfred Osgood, it was 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 or to any other oryzomyine then known, so that it is now placed in its own genus, Eremoryzomys. The Brazilian genus Drymoreomys, named in 2011, is probably the closest relative of Eremoryzomys. Eremoryzomys has a limited distribution in the dry upper valley of the Marañón River in central Peru, but may yet contain more than one species.
Transandinomys talamancae is a rodent in the family Cricetidae that occurs from Costa Rica to southwestern Ecuador and northern Venezuela. Its habitat consists of lowland forests up to 1,500 m (5,000 ft) above sea level. With a body mass of 38 to 74 g, it is a medium-sized rice rat. The fur is soft and is reddish to brownish on the upperparts and white to buff on the underparts. The tail is dark brown above and lighter below and the ears and feet are long. The vibrissae (whiskers) are very long. In the skull, the rostrum is long and the braincase is low. The number of chromosomes varies from 34 to 54.
Aegialomys xanthaeolus, also known as the yellowish oryzomys or yellowish rice rat, is a species of rodent in the family Cricetidae. It belongs to the genus Aegialomys in tribe Oryzomyini, which was not recognized as distinct from Oryzomys until 2006. It is found in coastal Ecuador and Peru. Though it is currently the only formally recognized mainland species of Aegialomys, at least one other exists. The specific name is sometimes incorrectly spelled "xantheolus", without the second "a".
Scolomys is a genus of rodent in the tribe Oryzomyini of the family Cricetidae. Some evidence suggests that it is related to Zygodontomys. It is characterized, among other traits, by spiny fur. It contains two species, S. melanops and S. ucayalensis.
Sigmodontomys is a genus of rodent in the tribe Oryzomyini of family Cricetidae. It is related to Nectomys and Melanomys and used to be included in Nectomys. It includes two species, Sigmodontomys alfari and the much rarer Sigmodontomys aphrastus, but whether these are indeed each other's closest relatives is uncertain.
Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of the family Cricetidae. It includes about 120 species in about thirty genera, distributed from the eastern United States to the southernmost parts of South America, including many offshore islands. It is part of the clade Oryzomyalia, which includes most of the South American Sigmodontinae.
Cerradomys maracajuensis, also known as the Maracaju oryzomys, is a rodent species from South America. It is terrestrial and is found in gallery forests in Bolivia, Paraguay and nearby Brazil and Peru. It was first discovered near the Brazilian city of Maracaju.
Carletonomys cailoi is an extinct rodent from the Pleistocene (Ensenadan) of Buenos Aires Province, Argentina. Although known only from a single maxilla with the first molar, its features are so distinctive that it is placed in its own genus, Carletonomys. Discovered in 1998 and formally described in 2008, it is part of a well-defined group of oryzomyine rodents that also includes Holochilus, Noronhomys, Lundomys, and Pseudoryzomys. This group is characterized by progressive semiaquatic specializations and a reduction in the complexity of molar morphology.
Transandinomys is a genus of rodents in the tribe Oryzomyini of family Cricetidae. It includes two species—T. bolivaris and T. talamancae—found in forests from Honduras in Central America south and east to southwestern Ecuador and northwestern Venezuela in northern South America. Until 2006, its members were included in the genus Oryzomys, but phylogenetic analysis showed that they are not closely related to the type species of that genus, and they have therefore been placed in a new genus. They may be most closely related to genera like Hylaeamys and Euryoryzomys, which contain very similar species. Both species of Transandinomys have had eventful taxonomic histories.
Handleyomys is a genus of Central and South American rodents in the tribe Oryzomyini of family Cricetidae. It was first described in 2002 to include two species from the Colombian Andes which were previously included in distinct and unrelated genera, Aepeomys and Oryzomys, but which turned out to be closely related. Later, in 2006, six other species were provisionally added from Oryzomys; these are expected to be placed in new genera in the future.
In anatomy, posterolateral palatal pits are gaps at the sides of the back of the bony palate, near the last molars. Posterolateral palatal pits are present, in various degrees of development, in several members of the rodent family Cricetidae. Many members of the family lack them or have only simple pits, but Arvicolinae and Oryzomyini have more highly developed posterolateral palatal pits. Posterolateral palatal pits are also present in some other rodents, including Glis, Jaculus, Hystrix, Abrocoma, Ctenomys, Chinchilla, and Lagidium.
Drymoreomys is a rodent genus in the tribe Oryzomyini that lives in the Atlantic Forest of Brazil. The single species, D. albimaculatus, is known only from the states of São Paulo and Santa Catarina and was not named until 2011. It lives in the humid forest on the eastern slopes of the Serra do Mar and perhaps reproduces year-round. Although its range is relatively large and includes some protected areas, it is patchy and threatened, and the discoverers recommend that the animal be considered "Near Threatened" on the IUCN Red List. Within Oryzomyini, Drymoreomys appears to be most closely related to Eremoryzomys from the Andes of Peru, a biogeographically unusual relationship, in that the two populations are widely separated and each is adapted to an arid or a moist environment.
