for National Geographic News
A newly found species small enough to fit in the palm of a hand is North America's oldest known primate, according to a new study.
Christopher Beard, a paleontologist at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, recently discovered fossils of the 55-million-year-old creature on the Gulf Coastal Plain of Mississippi.
"They are very, very primitive relatives of living primates called tarsiers, which live today in Southeast Asia," Beard said.
But the layer of rock in which the new fossils were found raises the controversial possibility that primates appeared in North America before their close relatives showed up in Europe, as previous studies had suggested, Beard added.
A paper on the find appears this week in the journal Proceedings of the National Academy of Sciences.
(The research was sponsored in part by a grant from the National Geographic Society's Committee for Research and Exploration. National Geographic News is owned by the National Geographic Society.)
Land Bridge Crossing
The discovery suggests that Teilhardina primates migrated to North America across the Bering land bridge from Asia, Beard said. Then the creatures proceeded to Europe across an Atlantic land bridge that emerged thousands of years later.
Previous research had suggested the primates reached the Americas via a westward route instead, from Asia through Europe. But that path was submerged at the time the primates show up in ancient Mississippi, Beard said.
At that time, the world was undergoing an ancient global warming event known as the Paleocene-Eocene Thermal Maximum, or PETM. Many scientists believe the PETM is analogous to what the world is experiencing today due to human-caused increases in greenhouse gases such as carbon dioxide.
Unlike today, however, there were no polar ice caps. In fact, sea levels were falling as Earth's shifting landmasses opened up huge ocean basins. (Related: "Volcanic Activity Triggered Deadly Prehistoric Warming" [April 26, 2007].)
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