//Monkeys made their way from Africa to South America at least twice

Monkeys made their way from Africa to South America at least twice

Peru

Ancient monkey fossils were found in Peru

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Two lineages of ancient monkey migrated from Africa to South America more than 30 million years ago. But we aren’t sure which ones got there first.

Monkeys originated in Africa and the first group known to have reached South America are thought to have migrated there up to 40 million years ago, when the land masses were probably between 1500 and 2000 kilometres apart, around a quarter of the distance now.

But recent fossil discoveries, including that of fossilised teeth from a second lineage of African monkey, tell a slightly different story.

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Erik Seiffert at the University of Southern California and his colleagues analysed the fossilised teeth, which were originally discovered in Santa Rosa, Peru. “This discovery was just so incredibly fascinating, I was very excited,” says Seiffert.

He and his colleagues analysed four fossilised teeth and discovered that their shape doesn’t match that of the only previously known group of ancient monkeys from South America, called platyrrhines. Instead, the teeth look much more like those of an extinct group of African monkeys called the parapithecids.

“Mammalian teeth are extremely diverse in shape, and so, for palaeontologists, are almost like fingerprints that sometimes allow us to identify species from only a single tooth or even a partial tooth,” says Seiffert.

If they do belong to this group, it will be the first time parapithecid fossils have been discovered in South America, says Seiffert. It suggests that the ancestors of platyrrhine monkeys aren’t the only ones who made the trans-Atlantic voyage, he says.

Both lineages are thought to have crossed the ocean on a large raft of floating vegetation. Fossil dating indicates that the second lineage of monkey made it across the Atlantic Ocean between 35 and 32 million years ago. This time frame coincided with a major drop in sea level that could have helped the animals to migrate by shortening their journey.

The team estimates that two lineages existed alongside each other for 11.5 million years. It isn’t clear which group got there first. The oldest platyrrhine fossil is about 34 million years old, younger than previously thought, and closer to the age of the newly discovered parapithecid fossils, says Seiffert.

“There is no reason to think that platyrrhines arrived earlier than parapithecids,” says Seiffert. “In fact, the two lineages could have come over around the same time.”

Journal reference: Science, DOI: 10.1126/science.aba1135

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