Adult and juvenile fossil specimens of Isostylomys laurdillardi, a giant rodent that lived in South America between 9 and 6.8 million years ago (Miocene epoch), have been found by paleontologists, raising questions about classification within the rodent family Dinomyidae. Isostylomys laurdillardi. Image credit: Andres Rinderknecht et al. Dr. Andres Rinderknecht of the Museo Nacional de Historia Natural in Uruguay and his colleagues describe the new...