Two nearly complete sets of fossilized animal remains from 130-million-year-old rocks in China are revealing fresh details about the size and dietary habits of ancient mammals. The newly described finds counter the common presumption that such creatures remained small and ecologically suppressed until dinosaurs became extinct about 65 million years ago.
The fossils were unearthed from volcanic ash laid down by an ancient eruption. Many of the entombed animals have been preserved in their original three-dimensional forms, says Jin Meng, a paleontologist at the American Museum of Natural History in New York.
The larger of the two finds, a 1-meter-long mammal dubbed Repenomamus giganticus