Did Primates Arrive in North America Before They Arrived in Europe?

That is the question raised by the discovery of a new species of Teilhardina (you can go here to learn more about Teilhardina). The new species, Teilhardina magnoliana, was discovered in Mississippi and is written up in PNAS (unfortunately, it is not open access, so if someone could send me a copy I would appreciate it). National Geographic also has a story on it. From National Geographic:

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.

The article has its critics. One is Philip Gingerich who has suggested in the past that primates arrived from Europe. According to Gingerich:

Gingerich’s study was based largely on comparison of carbon isotope signatures from the fossil beds where the ancient primates were found in Europe, Asia, and Wyoming. Scientists use the signatures to identify and date events within the PETM.
Beard acknowledges that his study lacks an appropriate carbon isotope signature.
Gingerich said the missing data makes Beard’s claims impossible to validate.
Sea level rose and fell several times during the PETM, making geologic markings difficult to interpret, Gingerich added.
“We’re talking about events here that could be separated by as little as 10 or 15 or 20 thousand years,” he said.

Update: I have the paper now, a big thanks to everyone who sent a copy!