The acouchis are rodents belonging to the family Dasyproctidae from the Amazon basin. They are generally smaller than agoutis and have very short tails, while agoutis lack tails. For this reason the acouchis are also called tailed agoutis.
The lowland paca, also known as the spotted paca, is a large rodent found in tropical and sub-tropical America, from east-central Mexico to northern Argentina, and has been introduced to Cuba and Algeria.
The agouti or common agouti is any of several rodent species of the genus Dasyprocta. They are native to Middle America, northern and central South America, and the southern Lesser Antilles. Some species have also been introduced elsewhere in the West Indies. They are related to guinea pigs and look quite similar, but they are larger and have longer legs. The species vary considerably in colour, being brown, reddish, dull orange, greyish, or blackish, but typically with lighter underparts. Their bodies are covered with coarse hair, which is raised when alarmed. They weigh 2.4–6 kg (5.3–13.2 lb) and are 40.5–76 cm (15.9–29.9 in) in length, with short, hairless tails.
Caviomorpha is the rodent infraorder or parvorder that unites all New World hystricognaths. It is supported by both fossil and molecular evidence. The Caviomorpha was for a time considered to be a separate order outside the Rodentia, but is now accepted as a genuine part of the rodents. Caviomorphs include the extinct Heptaxodontidae, the extinct Josephoartigasia monesi and extant families of chinchilla rats, hutias, guinea pigs and the capybara, chinchillas and viscachas, tuco-tucos, agoutis, pacas, pacaranas, spiny rats, New World porcupines, coypu and octodonts.
The Hystricognathi are an infraorder of rodents, distinguished from other rodents by the bone structure of their skulls. The masseter medialis passes partially through a hole below each eye socket and connects to the bone on the opposite side. This, together with their lack of an infraorbital plate and the relative size of the infraorbital foramen, distinguishes hystricognaths from other rodent groups.
The term Hystricomorpha has had many definitions throughout its history. In the broadest sense, it refers to any rodent with a hystricomorphous zygomasseteric system. This includes the Hystricognathi, Ctenodactylidae, Anomaluridae, and Pedetidae. Molecular and morphological results suggest the inclusion of the Anomaluridae and Pedetidae in Hystricomorpha may be suspect. Based on Carleton & Musser 2005, these two families are discussed here as representing a distinct suborder Anomaluromorpha.
The red-rumped agouti, also known as the golden-rumped agouti, orange-rumped agouti or Brazilian agouti, is a species of agouti from the family Dasyproctidae.
The Central American agouti is a species of agouti from the family Dasyproctidae. The main portion of its range is from Chiapas and the Yucatan Peninsula, through Central America, to northwestern Ecuador, Colombia and far western Venezuela. A highly disjunct population is found in southeastern Peru, far southwestern Brazil, Bolivia, western Paraguay and far northwestern Argentina. The disjunct population has been treated as a separate species, the brown agouti, but a major review of the geographic variation is necessary. The Central American agouti has also been introduced to Cuba and the Cayman Islands.
Anomaluromorpha is a clade that unites the anomalures, springhares, and zenkerella. It has alternately been designated as either a suborder or infraorder. Most recently, Carleton & Musser 2005 recognized it as one of five suborders of rodents.
Hydrochoerinae is a subfamily of Caviidae, consisting of two living genera, Hydrochoerus, the capybaras, and Kerodon, the rock cavies. In addition, a number of extinct genera related to capybaras should also be placed in this subfamily. The taxonomy of Hydrochoerinae is confused because, until 2005, living capybaras and their extinct relatives were placed in their own family, Hydrochoeridae. Recent molecular phylogenetic studies recognize a close relationship between Hydrochoerus and Kerodon, supporting placement of both genera in a subfamily of Caviidae. Paleontological classifications have yet to incorporate this new taxonomy, and continue to use Hydrochoeridae for all capybaras, while using Hydrochoerinae for the living genus and its closest fossil relatives such as Neochoerus. The taxonomy of fossil hydrochoerines is also in a state of flux. In recent years, the diversity of fossil hydrochoerines has been substantially reduced. This is largely due to the recognition that capybara molar teeth show strong variation in shape over the life of an individual. In one instance, material once referred to four genera and seven species on the basis of differences in molar shape is now thought to represent differently aged individuals of a single species, Cardiatherium paranense.
The Eocardiidae are an extinct family of caviomorph rodents from South America. The family is probably ancestral to the living family Caviidae, which includes cavies, maras, and capybaras and their relatives. McKenna and Bell (1997) divided eocardiids into two subfamilies, Luantinae for two of the oldest genera and Eocardiinae for remaining genera. Kramarz (2006) has recommended the abandonment of these subfamilies, as the genera placed in Luantinae appear to represent basal eocardiids, rather than a specialized side branch. The latter hypothesis had been proposed by Wood and Patterson (1959).
The Coiban agouti is a species of rodent in the family Dasyproctidae. It is endemic to the island of Coiba (Panama) and resembles the more widespread Central American agouti. It is threatened by habitat loss.
The crested agouti is a species of rodent in the family Dasyproctidae. It is endemic to Guyana and Suriname. Its taxonomic status is uncertain and it may be synonymous with Dasyprocta leporina, leading the IUCN to rate it as Data Deficient.
The Orinoco agouti is a species of rodent in the family Dasyproctidae. It is endemic to Delta Amacuro in Venezuela, where it is found in areas with rainforest or mangroves.
Kalinowski's agouti is a species of rodent in the family Dasyproctidae. It is endemic to southeast Peru. It occurs at elevations of up to 3,080 metres (10,100 ft) asl. It is threatened by habitat loss.
The armored rat is a species of rodent in the family Echimyidae. It is monotypic within the genus Hoplomys. It is found in Latin America, from northern Honduras to northwest Ecuador. It possesses a range of spines on its back and sides of the body.
Cephalomyidae is an extinct family of caviomorph rodents from South America. The specific relationships of the family are uncertain, and affinities to both chinchilloid and cavioid rodents have been supported. Most recently, Kramarz in 2005 performed a phylogenetic analysis supporting a relationship to the Cavioidea, as represented by Eocardiidae, although more recent analyses have placed them among the chinchilloids as relatives of the giant neoepiblemid rodents. McKenna and Bell (1997) questioned the validity of the family, placing the cephalomyid genera then known in Dasyproctidae, but Kramarz (2001) subsequently reasserted the distinctiveness of cephalomyids.
