Hydrochoerinae is a subfamily of

Caviidae Caviidae, the cavy family (biology), family, is composed of rodents native to South America and includes the domestic guinea pig, wild cavies, and the largest living rodent, the capybara. They are found across South America in open areas from mo ...

, consisting of two living genera, ''

Hydrochoerus The genus ''Hydrochoerus'' contains two living and three extinct species of rodents from South America, the Caribbean island of Grenada, California and Panama. Capybaras are the largest living rodents in the world. The genus name is derived from ...

'', the

capybara The capybara or greater capybara (''Hydrochoerus hydrochaeris'') is the largest living rodent, native to South America. It is a member of the genus '' Hydrochoerus''. The only other extant member is the lesser capybara (''Hydrochoerus isthmi ...

s, 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.McKenna, Malcolm C., and Bell, Susan K. 1997. ''Classification of Mammals Above the Species Level.'' Columbia University Press, New York, 631 pp. Recent

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies recognize a close relationship between ''Hydrochoerus'' and ''Kerodon'', supporting placement of both genera in a subfamily of

. 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''.

References

Cavies Mammal subfamilies Taxa named by John Edward Gray {{rodent-stub