Rukwapithecus (foreground) and Nsungwepithecus (background). MAURICIO ANTONThe genes of living primates tell us that the ape lineage, which includes humans, diverged from the Old World monkeys such as baboons and macaques during the late Oligocene period, between 25 and 30 million years ago. But fossils from both groups only date back to 20 million years ago. Now, a team of paleontologists have found two new species in Tanzania’s Rukwa Rift Basin that help to fill this gap in the fossil record. Their findings are published in Nature today (May 15).
The first new fossil was unearthed in 2011, when the team found a molar belonging to the oldest known Old World monkey or cercopithecoid, which they named Nsungwepithecus gunnelli. A year later and 15 kilometers away, they found the oldest known remains of a hominoid or “ape”—a jawbone and four teeth belonging to a new species that they dubbed Rukwapithecus fleaglei.
Both species were found in sediments that date to precisely 25.2 million years ago. “As early as [that], we already have forms that significantly diversified from one another,” said Nancy Stevens from Ohio University, who led the study. “That implies that the hominoid-cercopithecoid divergence was well underway.”
“It seems that a good divergence date might be between 26 and 27 million years ago,” said ...
