An international team of paleontologists has discovered two ancient species of South American rodents, including the oldest chinchilla, a discovery that substantiates what might be the earliest grasslands in the world. An image shows the fossilized jaw of the oldest chinchillid rodent, Eoviscaccia frassinettii, which is related to the modern chinchilla (M. Ellison / AMNH) The two new species lived near a chain of volcanoes about 32.5 million years...