Scientists Date the Split between Old World Monkeys and Apes
In a new discovery of two fossils from the East African rift, scientists were able to find the oldest evidence of when Old World monkeys and apes separated. The research team from Ohio University believes that the two new fossils belonged to the two major groups of primates, which are the hominoids and the cercopithecoids. The hominoids are made up of apes and humans, and the cercopithecoids are made up of Old World monkeys that include baboons and macaques. These different groups of primates have been documented to split a long time ago, but this finding is the first one to be able to provide the new date of the split at nearly 25 million years ago.
The two fossils that were found specifically in the Rukwa Rift Basin of Tanzania are the hominoid, Rukwapithecus fleaglei and the cercopithecoid, Nsungwepithecus gunnelli. The scientists grouped these two primates based on teeth and jaw pieces. These findings were significant because not a lot of fossils have been discovered to exist at that particular time.
"The late Oligocene is among the least sampled intervals in primary evolutionary history, and the Rukwa field area provides a first glimpse of the animals that were alive at that time from Africa south of the equator," the leader of the paleontological team, Nancy Stevens explained. Stevens is an associate professor of paleontology from the University's Heritage College of Osteopathic Medicine. The Oligocene time period dates from 34 to 23 millions years ago when these primates were believed to be thriving. Research into this time period has been limited due to the lack of fossils that contained evidence of existence during that specific time.
"The rift setting provides an advantage in that it preserves datable materials together with these important primate fossils," She added. The research team was able to determine the age of the fossils by dating the minerals of the rocks within the region. The team used a MicroCT scanner to recreate a three-dimensional viewpoint of the fossils and used these images to compare the specimens to several other fossils.
These findings help provide a better understanding of when these two primates actually diverged. The U.S. National Science Foundation, the Leakey Foundation and the National Geographic Society funded the study. It was published in Nature.