Pliocene rodents

Castoroides (from Latin castor (beaver) and -oides (like)), or the giant beaver, is an extinct genus of enormous, bear-sized beavers that lived in North America during the Pleistocene. Two species are currently recognized, C. dilophidus in the Southeastern United States and C. ohioensis in most of North America. C. leiseyorum was previously described from the Irvingtonian age but is now regarded as an invalid name. All specimens previously described as C. leiseyorum are considered to belong to C. dilophidus.

Ceratogaulus is an extinct genus of rodents, a member of the extinct fossorial (burrowing) rodent family Mylagaulidae. Ceratogaulus is one of two rodent genera with horns (along with fellow mylagaulid Mylagaulus) and is the smallest known horned mammal. Ceratogaulus lived in North America from the late Miocene to the early Pliocene epochs, 16.3 to 5.3 million years ago. Ceratogaulus (and to a lesser extent Mylagaulus) have sometimes been nicknamed "horned gophers", though they are only distantly related to true gophers.

Josephoartigasia is an extinct genus of enormous dinomyid rodent from the Early Pliocene to Early Pleistocene of Uruguay. Its closest living relative is the pacarana. Josephoartigasia is named after Uruguayan national hero José Artigas. It contains two species: J. magna, described in 1966 based on a left mandible, and J. monesi, described in 2008 based on a nearly complete skull. Both are reported from the San José Member of the Raigón Formation by the Barrancas de San Gregorio along Kiyú beach.