Fossil of Seafaring Monkey Found in North America

A 21-million-year-old monkey fossil was found in Panama, suggesting monkeys made it across the ocean that separated the two continents. The monkey was likely similar to a modern-day capuchin, seen here. Yves Herman/REUTERS

Monkeys don't like staying put. Although they originated in Africa, they somehow made their way across the Atlantic to South America about 26 million years ago, according to New Scientist. Within several million years, they were distributed widely throughout the continent.

But nobody thought they had made it to North America until the Isthmus of Panama formed, which is generally thought to have happened less than 4 million years ago. But researchers have now found the 21-million-year old remains of a monkey in Panama, suggesting that some of these animals had made their way to North America many millions of years before the isthmus formed, according to a study published April 20 in the journal Nature.

"Prior to this discovery, New World monkeys were thought to have evolved in isolation on South America, cut off from North America by a wide seaway," said Jonathan Bloch, the study's first author and a researcher with the University of Florida, in a statement.

Scientists have found fossils of other animals that made it across the ocean separating the continents, which varied in size but was at times thought to be about 100 miles wide. But the new monkey is definitely the oldest example on record. The previous record-holder was a giant sloth, dated to about 8.5 to 9 million years ago.

The monkey fossil, which consists of seven teeth, was unearthed during an expansion of the Panama Canal and then analyzed by researchers from the Smithsonian Tropical Research Institute and elsewhere.

The scientists have named the monkey Panamacebus transitus and placed it in the same family as capuchins and spider monkeys.