When David A. Grimaldi, an entomologist at the American Museum of Natural History in New York, gazed into a 92-million-year-old piece of amber that had been donated to the museum about 6 months before, he saw something rather unexpected. "But I knew exactly what it was," he adds.
It was the fossil of a primitive ant. The surprise is that the species of ant must be 40 million years older than any others of its subfamily, Grimaldi and his museum colleague Donat Agosti report in the December 15 Proceedings of the National Academy of Sciences. The finding forces researchers to reevaluate their ideas about the early evolution of these tiny insects.