The Oldest North American Primate: 55 Million Years Old

Today, North America is a land of prairies and oak or coniferous forests. But once, it was a tropical paradise and like any tropical environment, monkeys were present. Now, a research published in "Proceedings of the National Academy of Sciences" describes the earliest-known primate to inhabit North America. The 55.8 million-year-old creature weighed about 28g, measured 7.5cm long and fed on insects and fruits. The team has mainly found teeth of the creature.

"The species likely scampered over a now-vanished land bridge connecting Siberia to Alaska. The tiny immigrant was called Teilhardina magnoliana. For his time, he would have been about the smartest animal around. But that doesn't mean he was thinking deep thoughts. Primates almost always have relatively larger brains than other mammals," said author Christopher Beard, paleontologist of the Carnegie Museum of Natural History, in Pittsburgh.

"It's a small, primitive primate. In some ways, it would have looked more like a teeny, tiny monkey than a small lemur," added Beard.

Still, the first monkeys appeared more than 10 million years later. This animal was not an ancestor of the New World monkeys (like capuchin or howler monkeys), but it was from the group of tarsiers, which today survive only as relicts on islands in Southeast Asia (Philippines, Borneo and Sulawesi) and are mainly nocturnal insectivorous. The look of Yoda, from Star Wars, was inspired by these small creatures.

Related fossils species have been discovered in China, Belgium, France, southern Texas and Wyoming.
"The new species predated the Wyoming one and came from a time period when a route from Asia was the likely path into North America," said Beard.

The Texan fossils are 42 million years old.

Scientists have argued for long how primates passed from Asia into Europe. One hypothesis says they came from Siberia, the opposite one claims they went overland from Europe, passing through Greenland, in a period when the continents were differently positioned. The new fossil teeth were discovered near Meridian, Mississippi, close to the former coastline of the Gulf of Mexico.

They predate any European primate fossils, pointing that the Siberian theory could be the correct one and that the migration could have taken place 10 million years after the dinosaur disappearance. The same Bering land bridge had been used by many migrations in time, in a direction and the other, including dinosaurs, horses, camels, bears, wolves, pandas, bisons, mammoths, rhinoceroses, tapirs, beavers, marmots, squirrels, elk, moose, deer, sheep, goats, frogs, lizards, snakes and even humans, coming from Siberia 30,000 to 12,000 years ago.

"The world was in the middle of a drastic warming period and a dramatic radiation of mammal species. In this ancient, ice-free world, Alaska must have been a tropical paradise," said Beard.