Cavia
Cavia is a genus in the subfamily Caviinae that contains the rodents commonly known as guinea pigs or cavies. The best-known species in this genus is the domestic guinea pig, "Cavia porcellus", a meat animal in South America and a common household pet outside of that continent. Former taxonomic controversy. "Cavia" is classified in order Rodentia, although there was once a minority belief in the scientific community that evidence from mitochondrial DNA and proteins suggested the Hystricognathi might belong to a different evolutionary offshoot, and therefore a different order. If this had been so, it would have been  an example of convergent evolution. However, this uncertainty is largely of historical interest, as abundant molecular genetic evidence now conclusively supports classification of "Cavia" as rodents. This evidence includes draft genome sequences of "Cavia porcellus" and several other rodents. Species. Historically, there has been little consensus in regard to the number of Cavia forms and their taxonomic affiliations. Morphological characters differentiating between Cavia species are limited and levels of inter and intra specific morphologic variation have not been well documented, thus, interpretations have varied and resulted in very different taxonomic conclusions. Three scientists disagreed on the number of species, Tate(1935 ) recognized 11 species, while Cabrera(1961) recognized 7, and Huckinghaus(1961) recognized only 3. Recent scientific compilations have generally followed either Cabrera or Huckinghaus. At least five wild species of guinea pig are recognised, in addition to the domestic form: Some authors also recognise the following additional species: In addition, four fossil species have been identified: