Three new extinct monkeys that lived in what is now Peru approximately 36 million years ago have been discovered by a team of paleontologists led by Dr Kenneth Campbell of the Natural History Museum of Los Angeles County. The characteristics of the teeth of these early monkeys provide the first evidence that South American monkeys actually have an African ancestry.
This is an artist rendering of what South America’s oldest known monkey, Perupithecus ucayaliensis, might have looked like; it was about the size of a squirrel, but with a longer tail, and probably weighed less than 250 grams. Image credit: Jorge González.
Until now, the oldest fossil records of New World monkeys – monkeys found in South America and Central America – have come from Salla, Bolivia and date to 26 million years ago (Late Oligocene epoch).
The new fossils indicate that monkeys first arrived in South America at least 36 million years ago.
South America was an island continent for millions of years. Geographically isolated from Africa as a result of plate tectonics more than 65 million years ago, this continent witnessed the evolution of many unfamiliar groups of animals and plants.
From time to time, animals more familiar to us today managed to arrive to this island landmass, their remains appearing abruptly in the fossil record.
Yet, the earliest phases of the evolutionary history of monkeys in South America have remained cloaked in mystery.
Long thought to have managed a long transatlantic journey from Africa, evidence for this hypothesis was difficult to support without fossil data.
Dr Campbell and his co-authors discovered the first of the new fossils in 2010, but because it was so strange to South America, it took an additional two years to realize that it was from a primitive monkey.
Mounting evidence came as a result of further efforts to identify tiny fossils associated with the first find.
Dr Campbell, who is a corresponding author of the paper published in the journal Nature, said these fossils push back the colonization of South America by monkeys by at least 10 million years.
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Mariano Bond et al. Eocene primates of South America and the African origins of New World monkeys. Nature, published online February 04, 2015; doi: 10.1038/nature14120
