"This is the first time that the complete skull of an ape of this age has been found ... it is a highly important fossil and it will certainly put Uganda on the map in terms of the scientific world," Martin Pickford, a paleontologist from the College de France in Paris, told journalists in Kampala.
The fossilised skull belonged to a male Ugandapithecus Major, a remote cousin of today's great apes which roamed the region around 20 million years ago.
The team discovered the remains on July 18 while looking for fossils in the remnants of an extinct volcano in Uganda's remote northeastern Karamoja region.
Preliminary studies of the fossil showed that the tree-climbing herbivore, roughly 10 years old when it died, had a head the size of a chimpanzee?s but a brain the size of a baboon?s, Pickford said.
Brigitte Senut, a professor at the Musee National d?Histoire Naturelle, said that the remains would be taken to Paris to be x-rayed and documented before being returned to Uganda.
"It will be cleaned in France, it will be prepared in France... and then in about one year's time it will be returned to the country," Senut said.
Paleontologists from France have been visiting Uganda on expeditions funded by the French government for the past 25 years, Senut said.
The least developed region in Uganda, the arid plains of Karamoja have in recent years been largely pacified following decades of insecurity linked to armed cattle raiding between nomad communities.