| Isthmomys | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Cricetidae |
| Subfamily: | Neotominae |
| Tribe: | Reithrodontomyini |
| Genus: | Isthmomys Hooper & Musser, 1964 |
| Type species | |
| Megadontomys flavidus [1] | |
| Species | |
Isthmomys is a genus of rodent in the family Cricetidae, belonging to the tribe Reithrodontomyini. Species are:
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).
The Neotominae are a subfamily of the family Cricetidae. They consist of four tribes, 16 genera, and many species of New World rats and mice, predominantly found in North America. Among them are the well-known deer mice, white-footed mice, packrats, and grasshopper mice.
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.
Vesper mice are rodents belonging to the genus Calomys. They are widely distributed in South America. Some species are notable as the vectors of Argentinian hemorrhagic fever and Bolivian hemorrhagic fever.
The aquatic rat, Ecuador fish-eating rat, fish-eating rat or Ecuadoran ichthyomyine is a South American species of semiaquatic rodent in the family Cricetidae. It is the only species in the genus Anotomys. This species is currently considered endangered. It is thought to be nocturnal and feeds on aquatic arthropods and insects. It is found in small ranges along the Andes.
The yellow isthmus rat is a species of rodent in the family Cricetidae. It is found only in Panama. It was discovered by W. W. Brown Jr. on the southern slope of Volcan de Chiriqui. He found it common in the upland forest from 1000 to 1500m, but no specimens were taken above or below these elevations. Museum records specify two isolated populations in western Panama, one at Cerro Colorado where R. Pine et al. collected in 1980 and at Cerro Hoya on the Azuero Peninsula by C. Handley in 1962. The presence of I. flavidus or a closely allied form in Costa Rica is probable, however, no specimens have been reported. There are no currently known fossil records of Isthmomys.
The Mount Pirri isthmus rat is a species of rodent in the family Cricetidae.
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.
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.
Nephelomys devius, also known as the Talamancan oryzomys, Boquete rice rat, Chiriqui rice rat, or montane rice rat, is a species of rodent in the genus Nephelomys of family Cricetidae. It is found in cloud forest in the highlands of Costa Rica and western Panama.
Nephelomys keaysi, also known as Keays's oryzomys or Keays's rice rat, is a species of rodent in the genus Nephelomys of family Cricetidae. It is found from southeastern Peru to northern Bolivia on the eastern slope of the Andes in Yungas humid forest at altitudes of 1000 to 2600 m. Although its continued existence is not in serious danger and it is listed as "least concern", destruction of its habitat may pose a threat to some populations.
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.
The Tres Marías island mouse or Tres Marías deer mouse is a species of rodent in the family Cricetidae. It is found only on the Islas Marías off the west coast of Mexico. When last assessed, it was common on María Cleofás Island, but rare or absent on the other, more disturbed, islands.
Nephelomys pirrensis, also known as the Mount Pirre rice rat, is a species of rodent in the genus Nephelomys of family Cricetidae. Its type locality is at Mount Pirri or Pirre in eastern Panama, at an altitude of 4,500 feet (1,400 m), and it has also been recorded on Mount Tacarcuna.
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.
In rodent anatomy, the zygomatic plate is a bony plate derived from the flattened front part of the zygomatic arch (cheekbone). At the back, it connects to the front (maxillary) root of the zygomatic arch, and at the top it is connected to the rest of the skull via the antorbital bridge. It is part of the maxillary bone, or upper jaw, which also contains the upper cheekteeth. Primitively, rodents have a nearly horizontal zygomatic plate. In association with specializations in zygomasseteric system, several distinct morphologies have developed across the order.
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.
In mammals, ungual tufts are tufts of hairs at the base of claws of the forefeet and hindfeet. Their presence has been used as a character in cladistic studies of the Cricetidae, a large family of rodents.
Louise H. Emmons is an American zoologist who studies tropical rainforest mammals, especially rodents. She has conducted fieldwork in Gabon, Sabah (Borneo), Peru, and Bolivia. Her best known work is the field guide, Neotropical Rainforest Mammals: A Field Guide, first published in 1990, with a second edition in 1997.
 | This 'further reading' section may need cleanup.(May 2022) |