There has long been debate about the matter, but a recent discovery of anthropoid fossils including two previously unidentified species and one known species provides new clues.
The fossils are about 38 million years old and were uncovered in a rock formation in southern Libya. The anthropoids were small, rodent-size creatures that looked similar to larger, modern-day primates, but weighed just 4 to 17 ounces.
“At least one of these anthropoids appears to be clearly related to the older Asian form described in Myanmar,” said Jean-Jacques Jaeger, a paleontologist at the University of Poitiers in France and the study’s lead author. “This indicates that there was migration from Asia.”
But there is another possibility: that the anthropoids originated in Africa and migrated to Asia, and that they have even older ancestors in Africa that have not yet been discovered.
There is no fossil evidence that substantiates this theory today, but more digging is required, Dr. Jaeger said.
“We have to do much more work and we need more information about the older layers in Africa, which we are trying to find in Libya now,” he said.
But if it is the case that the anthropoids originated in Asia and migrated, this movement was key to the proliferation of the subspecies.
“In Asia they may have gone extinct,” Dr. Jaeger said. “The conditions were more difficult, and if this migration didn’t occur, there would not be the rise in anthropoids in the present world.”