A team of international scientists announced Wednesday the discovery of the oldest-known fossil primate skeleton, Archicebus achilles, uncovered in an ancient lake bed near the modern Yangtze River in China’s Hubei province.
Christopher Beard, curator of vertebrate paleontology at the Carnegie Museum of Natural History, said the fossil’s discovery has profound implications for understanding eras of human evolution that remain shrouded in mystery.
“The oldest fossils that we can find that are specifically human are about a tenth as old as this fossil that we have found today,” Beard said.
Though Archicebus achilles is a long way removed from specific human relatives, Beard said, our common past is important to consider.
“If we want to learn more about humanity, we also need to learn more about our close primate relatives, living and fossil,” he said.
While much is known about human evolution after our divergence from apes, truly understanding the history of our species demands looking back even further to when human lineage diverged from that of tarsier lineage, Beard said.
He and his team believe the 55 million-year-old Archicebus achilles is close to a point of common ancestry for both the human and tarsier branches of the evolutionary tree.
“The scientific question is, how do you turn a very primitive primate that might look something like a lemur into an animal that would look basically like a small monkey?” Beard said. “That’s the basic question we’re trying to address, and this new fossil goes a long way towards telling us that.”
The skeleton’s discovery not only addresses gaps in evolutionary history, but also underscores the role technology plays in research.
“We took the full force of modern science and we threw everything at this fossil,” Beard said. “The main goal is to figure out where does it fit in the evolutionary tree.”
Using high resolution digital imaging, the team built a 3-D image of the fossil. They also compared the skeleton to every other organism it could be compared to using new computer software to process the vast amounts of anatomical and genetic data.
At the end of the nearly five-year process of evaluating the data, Beard said they’ve come as close to the truth as possible in placing Archicebus achilles in the evolutionary tree before tarsiers and humans diverged.
“We went through a lot of cups of coffee,” Beard laughed.