19 August 2016
Long ago, one great ocean flowed between North and South America. When the narrow Isthmus of Panama joined the continents about 3 million years ago, it also separated the Atlantic from the Pacific Ocean. If this took place millions of years earlier, as recently asserted by some, the implications for both land and sea life would be revolutionary. Aaron O'Dea, staff scientist at the Smithsonian Tropical Research Institute (STRI), and colleagues writing in Science Advances firmly set the date at 2.8 million years ago.
"Recent scientific publications proposing the isolation of the two oceans between 23 to 6 million years ago rocked the generally held model of the continental connection to its foundations," said Jeremy Jackson, emeritus staff scientist at the Smithsonian. "O'Dea and his team set out to reevaluate in unprecedented, rigorous detail, all of the available lines of evidence--geologic, oceanographic, genetic and ecological data and the analyses that bear on the question of when the Isthmus formed."