Definition of "caviomorph"

Cavies are caviomorphs. Caviomorphs are tailless South American rodents that are characterized by having one pair of mammae (teats), four digits on the forefoot, and three digits on the hind foot, as well as special anatomical features of the head and jaws.

2003, Sharon Lynn Vanderlip, The Guinea Pig Handbook‎, page 11

Platypittamys was a caviomorph that lived in southern South America around 30 million years ago. […] Today caviomorphs are found in South America, but genetic studies show that they are descended from African rodents.

2008, Rebecca Stefoff, The Rodent Order‎, page 21

In beds of Deseadan age caviomorphs are represented by 6 families (9 genera), in the Santacrucian by 7 families (17 genera), and in the Hayquerian by 8 families (21 genera) (Marshall et al. In press b).

2012, Larry G. Marshall, “The Geat American Interchange—An Invasion-Induced Crisis for South American Mammals”, in Matthew Nitecki, editor, Biotic Crises in Ecological and Evolutionary Time, page 192