【英语时差8,16】化石的发现，填补研究的空白（在线收听）

 Researchers say they have identified animal fossils from twenty-seven-million years ago in what is now Ethiopia. The remains are from the middle of a time called the "missing years" or the "dark period." This is because scientists have so little information about the mammals that lived then. The period began thirty-two-million years ago, ended twenty-four-million years ago, after a land bridge formed with Eurasia. The remains include teeth, skull pieces and other bones. The scientists found them in a farming area about two-thousand meters above sea level, in the highlands of Ethiopia. Satellite pictures helped the researchers decide where to dig. The fossils came from about seventy different digs. The magazine Nature published the findings. The scientists say the fossils come from before large numbers of animals began to arrive in Africa from Europe and Asia. The fossils also show that some animals existed millions of years before scientists had thought. Scientists say they expect more discoveries to come about the mammals that lived during the so-called missing years.