Caviomorpha

Caviomorpha is a major clade of rodents within the infraorder Hystricognathi, comprising most of the New World hystricognaths. The group includes familiar species such as capybaras, guinea pigs, chinchillas, viscachas, agoutis, pacas, spiny rats, and degus, among others. They are distributed mainly in Central and South America, occupying a wide range of habitats from forests and grasslands to arid and high-altitude environments.

Biologically, caviomorphs are defined by features of the hystricognathous jaw and associated dental patterns that distinguish Hystricognathi from other rodents. They display substantial ecological and morphological diversity, ranging from large, herbivorous forms to smaller, gnawing species, and from terrestrial to more aquatic or semi-aquatic lifestyles.

Evolutionary history and biogeography: Caviomorphs are thought to have originated in Africa and reached South America via transatlantic rafting during the early to middle Eocene, around 40 million years ago. After arriving in South America, they underwent rapid diversification, giving rise to the major lineages present today and occupying a wide array of ecological roles. The group’s evolution is studied through fossil records and molecular data, contributing to our understanding of the broader biogeography of New World rodents.