Caviidae
Caviidae, the cavy 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 moist savanna to thorn forests or scrub desert. This family of rodents has fewer members than most other rodent families, with 19 species in 6 genera in 3 subfamilies.
Hypogeomys
Hypogeomys is a genus of rodents in the family Nesomyidae, found in Madagascar. There is one extant species, the Malagasy giant rat ("Hypogeomys antimena"), currently an endangered species with a restricted range. There is also another species known from subfossils from a few thousand years ago, "Hypogeomys australis". "H. antinema" measures , making it the largest rodent in Madagascar, while "H. australis" seems to have been slightly larger.