Prehistoric monkey teeth found in Panama rewrite simian migration

​Panama City: Seven little monkey teeth 21 million years old found during work on the Panama Canal are ripping up scientific theories on simian migration.

The fossils, found by US and Latin American researchers who wrote up the discovery in this week's edition of Nature, suggest that so-called New World monkeys -- ones that made it across the Atlantic from Africa to South America -- made it to North America 18 million years earlier than previously thought.

They are "the first evidence of a monkey on the North American continent before the isthmus of Panama connected it to South America 3.5 million years ago," the Panama-based Smithsonian Tropical Research Institute (STRI) said in a statement.

Scientists once thought that 200 kilometers (140 miles) of sea that separated North and South America in the Miocene era was a barrier to all mammal migration, and that monkeys only moved from South America to North America when Panama rose from an island-dotted sea and linked the two.