From New Scientist:
Alaskan gateway for first American monkey
* 08 March 2008
IT WAS only the size of a mouse, but it has the distinction of being the first primate to scurry into the New World.
Fossilised teeth of the monkey Teilhardina magnoliana have been found in rocks in Mississippi. They were dated as younger than its Asian relatives, but more ancient than those already found in Europe and North America.
The monkey must have colonised the Americas via Alaska, crossing from Asia via the Bering land bridge 55 million years ago, says Chris Beard of the Carnegie Museum of Natural History in Pittsburgh (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.071080105).
Analysis of the teeth suggests America’s first primate enjoyed a diet of fruit and insects.
Primate evolution: here.
Human Ice Age immigration into North America: here.
Estimates for peopling of Americas getting earlier:
Humans appear to have first entered the Americas
some 22,000 years ago, according to some archaeologists.