Panama fossils geologically key

Scientists in Panama have unearthed hundreds of animal fossils dating back 20 million years, which could shed more light on how and when the American continent became connected.

Geologists from the Smithsonian Institution, which has a permanent base in Panama, said engineers digging to widen the Panama Canal have uncovered more than 500 fossils, including teeth and bones of rodents and crocodiles that lived before a land bridge linked North and South America.

Scientists believe the South American and Caribbean tectonic plates collided about 15 million years ago, causing volcanic activity that eventually formed a thin strip of land linking the Americas and separating the Pacific and Atlantic oceans.