The rodent subfamily Sigmodontinae includes New World rats and mice, with at least 376 species. Many authorities include the Neotominae and Tylomyinae as part of a larger definition of Sigmodontinae. When those genera are included, the species count numbers at least 508. Their distribution includes much of the New World, but the genera are predominantly South American, such as brucies. They invaded South America from Central America as part of the Great American Interchange near the end of the Miocene, about 5 million years ago. Sigmodontines proceeded to diversify explosively in the formerly isolated continent. They inhabit many of the same ecological niches that the Murinae occupy in the Old World.
Transandinomys bolivaris, also known as the long-whiskered rice rat, is a rodent in the genus Transandinomys. 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 Nicaraguan rice rat, is a rodent in the genus Oryzomys of 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 Oryzomys couesi, which occurs in the same region.
Transandinomys talamancae is a rodent in the genus Transandinomys 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.
Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of 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.
Trombiculidae are a family of mites. Chiggers are often confused with jiggers - a type of flea. Several species of Trombiculidae in their larva stage bite their animal or human host and by embedding their mouthparts into the skin causing "intense irritation" or "a wheal, usually with severe itching and dermatitis",
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.
Oecomys sydandersoni is an arboreal species of rodent in the genus Oecomys. It lives in forest patches in a small area in eastern Bolivia. It is a medium-sized species, weighing about 45 g (1.6 oz), with mostly grayish and brownish fur and short and broad hindfeet with well-developed pads.
Hassalstrongylus is a genus of nematode worms that infect mostly muroid rodents from eastern North America to South America. The genus is part of the Nippostrongylinae and related to genera like Stilestrongylus.
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.
Polyplax spinulosa is a sucking louse (Anoplura) from the genus Polyplax. It occurs worldwide and commonly infects its type host, the brown rat, and related species like the black rat, Rattus pyctoris, Rattus nitidus, Rattus argentiventer, Rattus tanezumi, Rattus exulans, and Bandicota indica. It is also occasionally found in other rodents, such as the marsh rice rat in North America.
Amblyomma maculatum is a species of tick in the genus Amblyomma. Immatures usually infest small mammals and birds that dwell on the ground; cotton rats may be particularly favored hosts. Some recorded hosts include:
Euschoengastia peromysci is a mite in the genus Euschoengastia of the family Trombiculidae. Recorded hosts include the cotton mouse and marsh rice rat in Georgia; the northern short-tailed shrew, northern red-backed vole, northern flying squirrel, rock vole, white-footed mouse, and deermouse in Tennessee; and northern red-backed vole, southern bog lemming, masked shrew, and eastern red squirrel in North Carolina, among others.
Euschoengastia setosa is a mite in the genus Euschoengastia of the family Trombiculidae that mostly parasitizes small rodents and lagomorphs. Recorded hosts include marsh rice rat in Georgia; the deermouse in Tennessee; and the eastern red squirrel in North Carolina, among others.
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.
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:
Eutrombicula splendens is a species of chigger. In Florida, it has been found on the marsh rice rat and hispid cotton rat.
Laelaps is a genus of common parasitic mites in the family Laelapidae. Species, with their hosts, include:
