Hydrochoerinae is a subfamily of
Caviidae, consisting of two living genera, ''
Hydrochoerus
The genus ''Hydrochoerus'' contains two living and two 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 th ...
'', 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.
[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 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''.
References
Cavies
Mammal subfamilies
Taxa named by John Edward Gray
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