Caviomorpha is the rodent infraorder or parvorder that unites all New World hystricognaths. It is supported by both fossil and

molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

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 (giant hutias) and extant families of chinchilla rats, hutias, guinea pigs and the

capybara The capybaraAlso called capivara (in Brazil), capiguara (in Bolivia), chigüire, chigüiro, or fercho (in Colombia and Venezuela), carpincho (in Argentina, Paraguay and Uruguay) and ronsoco (in Peru). or greater capybara (''Hydrochoerus hydro ...

chinchilla Chinchillas are either of two species (''Chinchilla chinchilla'' and ''Chinchilla lanigera'') of crepuscular rodents of the parvorder Caviomorpha. They are slightly larger and more robust than ground squirrels, and are native to the Andes mount ...

s and viscachas, tuco-tucos, agoutis, pacas, pacaranas, spiny rats, New World porcupines, coypu and octodonts (Vassallo and Antenucci, 2015).

Origin

The first known rodent

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

in South America are represented by the three taxa ''Cachiyacuy contamanensis'', ''C. kummeli'', and ''Canaanimys maquiensis'', as well as teeth from ''Eobranisamys'' sp. (Dasyproctidae) and ''Eospina'' sp., the latter two found also in the Santa Rosa fauna from the late Eocene or early

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

. By the late

, all superfamilies and most families of caviomorphs are present in the fossil record. During this time, South America was isolated from all other continents. Several hypotheses have been proposed as to how hystricognath rodents colonized this island continent. Most require that a small group of these rodents traveled across ocean bodies atop a raft of mangroves or driftwood. The most common hypothesis suggests that the ancestor to all modern caviomorphs rafted across the Atlantic Ocean (then narrower) from Africa (Lavocat, 1969; Huchon and Douzery, 2000). This is supported by molecular results, which suggest that the

Phiomorpha The rodent parvorder or infraorder Phiomorpha comprises several living and extinct families found wholly or largely in Africa. Along with Anomaluromorpha and perhaps the extinct Zegdoumyidae, it represents one of the few early colonizations of ...

(as restricted to Bathyergidae, Petromuridae, and Thryonomyidae) are sister taxa to the Caviomorpha. In fact, until the discovery of the Laotian rock rat, all modern hystricognath families were restricted to South America, Africa, or had a range that included Africa ( Hystricidae). New World monkeys appear to have colonized South America from Africa at a similar time. Caviomorphs went on to colonize the West Indies as far as the Bahamas, reaching the Greater Antilles by the early Oligocene. This is commonly viewed as another example of oceanic dispersal, although a role for a possible land bridge has also been considered.

Diversity

Caviomorph rodents underwent an explosive diversification upon arrival into South America. They managed to outcompete other animals in rodent-like niches such as certain South American marsupials. Retaining predominantly herbivorous diets, they expanded their sizes to encompass a range from

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...

-sized echimyids to the

bison Bison are large bovines in the genus ''Bison'' (Greek: "wild ox" (bison)) within the tribe Bovini. Two extant and numerous extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'', found only in North Ame ...

-sized '' Phoberomys''. Their ecologies included burrowing gopher-like forms such as tuco-tucos, arboreal forms such as porcupines and certain spiny rats, running forms such as

mara Mara or MARA may refer to: Animals * Mara (mammal), a species of the cavy family *Mara the Lioness, in the movie ''Born Free'' Arts and entertainment Fictional characters * Mara (''Doctor Who''), an evil being in two ''Doctor Who'' serials *Mara, ...

s, and aquatic forms such as the

and nutria (Vassallo and Antenucci, 2015). Habitats include grasslands (maras), high mountains ( chinchillas and chinchilla rats), forest edges ( prehensile-tailed porcupines) and dense tropical forests ( pacas and

acouchi The acouchis (genus ''Myoprocta'') are rodents belonging to the family Dasyproctidae from the Amazon basin. They are generally smaller than agoutis and have very short tails (5 to 7 cm), while agoutis lack tails. For this reason the acouchis ...

s). Although many species of caviomorphs have migrated into Central America since the

Great American Interchange The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange and the Great American Faunal Interchange, was an important late Cenozoic paleozoogeographic biotic interchange event in which lan ...

, only a single living species, the North American porcupine, has naturally colonized North America north of Mexico (the extinct capybara '' Neochoerus pinckneyi'' also accomplished this feat). The nutria has been introduced into North America and has proven a highly successful

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

there.

Families

*Parvorder Caviomorpha - New World hystricognaths **†'' Luribayomys'' - '' incertae sedis'' **Superfamily Cavioidea *** Caviidae - cavies,

s, and maras *** Ctenomyidae - tuco-tucos *** Cuniculidae - pacas *** Dasyproctidae - agoutis and acouchis *** Dinomyidae - pacarana ***† Eocardiidae ***†''

Guiomys ''Guiomys'' is an extinct genus of cavioid rodent which lived in west central Patagonia of Argentina (Collón Curá Formation), Bolivia (Honda Group) and Peru ( Yahuarango Formation) during the Middle Miocene ( Laventan).

'' ***† Neoepiblemidae ***†'' Scotamys'' **Superfamily

Chinchilloidea 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 ...

*** Abrocomidae - chinchilla rats ***†'' Borikenomys'' - ''incertae sedis'' *** Chinchillidae - chinchillas and viscachas ***† Heptaxodontidae - giant hutias ***†'' Maquiamys'' - ''incertae sedis'' ***†'' Tsaphanomys'' - ''incertae sedis'' ** Superfamily

Erethizontoidea The New World porcupines, family Erethizontidae, are large arboreal rodents, distinguished by their spiny coverings from which they take their name. They inhabit forests and wooded regions across North America, and into northern South America. A ...

***Family Erethizontidae - New World porcupines **Superfamily Octodontoidea ***†'' Caviocricetus'' - ''incertae sedis'' ***†'' Dicolpomys'' - ''incertae sedis'' *** Echimyidae - spiny rats, coypus, and hutias ***†'' Morenella'' - ''incertae sedis'' *** Octodontidae - degus and relatives ***†'' Plateomys'' - ''incertae sedis'' ***†'' Tainotherium'' Turvey, Grady & Rye, 2006 - ''incertae sedis'' Note that some changes to this taxonomy have been suggested by

studies. The Dinomyidae is now thought to belong to the Chinchilloidea rather than the Cavioidea, the Abrocomidae may belong to the Octodontoidea, and the Hydrochaeridae may have evolved from within the Caviidae.

References

Citations

Sources

* Huchon, D. E. J. P. Douzery. 2001. "From the Old World to the New World: A molecular chronicle of the phylogeny and biogeography of hystricognath rodents". Molecular Phylogenetics and Evolution, 20:238-251. * Jenkins, P. D., C. W. Kilpatrick, M. F. Robinson, and R. J. Timmins. 2004. "Morphological and molecular investigations of a new family, genus and species of rodent (Mammalia: Rodentia: Hystricognatha) from Lao PDR". Systematics and Biodiversity, 2:419-454. * Lavocat, R. 1969. "La systématique des rongeurs hystricomorphes et la dérive des continents". C. R. Acad. Sci. Paris Sér. D., 269:1496-1497. * Marivaux, L. M. Vianey-Liaud, and J.-J. Jaeger. 2004. "High-level phylogeny of early Tertiary rodents: dental evidence". Zoological Journal of the Linnean Society, 142:105-134. * McKenna, Malcolm C., and Bell, Susan K. 1997. ''Classification of Mammals Above the Species Level.'' Columbia University Press, New York, 631 pp. * Opazo, J. C. 2005
A molecular timescale for Caviomorph rodents (Mammalia, Hystricognathi)
"Molecular Phylogenetics and Evolution", 37:932-937. * Vassallo, A. I., and C. D. Antenucci. 2015. Biology of Caviomorph Rodents: Diversity and Evolution. Sociedad Argentina para el Estudio de los Mamíferos (SAREM) Series A Mammalogical Research. * Wood, A. E. 1985. The relationships, origin, and dispersal of hystricognath rodents. pp 475–513 in ''Evolutionary relationships among rodents, a multidisciplinary approach'' (W. P. Luckett and J.-R. Hartenberger, eds.). Plenum Press, New York.

Origin

Diversity

Families

References

Citations

Sources

See also