Fossil Rodents With Supertough Teeth Found
Newfound species may have lived in world's earliest grassland, study says.
The newfound species, which lived 32 million years ago, are the second oldest ever found in South America after Peruvian mouselike and ratlike animals that date to some 41 million years ago.
The two fossils were found in an unlikely spot: central Chile's Tinguiririca River Valley (map), which is located near a chain of once active volcanoes.
For decades scientists thought fossils couldn't be found in volcanic rock, since it's usually too hot to preserve them. Somehow, though, ancient eruptions in the valley buried and preserved a fossil treasure trove.
"In this rugged terrain, the rock that accumulated from volcanic activity has preserved a record spanning 30 or 40 million years," said study co-author John Flynn, Frick Curator