article_snippet.sent: The continents of North and South America came together much earlier than previously thought, according to researchers who found evidence in rock deposits from ancient rivers in Colombia of the land bridge that connected the long-isolated landmasses.
article_snippet.sent: The continents of North and South America are linked at Panama, but there has been a debate about when this land bridge first appeared, with most experts placing this land bridge formation at about 3 million years ago.
article_snippet.sent: The new study, published on Thursday in the journal Science, presents evidence that the Panama land bridge formed at least 10 million years earlier.
article_snippet.sent: Smithsonian scientists are debating when this happened.
highlights_snippet.sent: Researchers had previously believed continents connected 3m years ago .
  