The world's oldest gorilla fossil has been found in Ethiopia, defying earlier assumptions about ape and human evolution, scientists at the National Museum of Ethiopia announced Wednesday.

Scientists believe the nine teeth unearthed during an excavation near Addis Ababa belong to a newly discovered type of 10-million-year-old gorilla. If their data is correct, the fossil could reveal several newtruths on ape and human evolution.

"We used to believe, based on genetic information, DNA studies and molecular studies, that the splits between chimpanzees and the human line on one side and the gorilla line on the other side … happened around eight million years ago," said paleontologist Berhane Asfaw, who helped unearth the fossil. "But based on this new information, the split had to happen before 10 million years ago. It means that information has to be adjusted in every textbook."

The new species — dubbed Chororapithecus abyssinicus, a combination of the names Chorora, the area where the fossil was found, and Abyssinia, Ethiopia's ancient name — could indicate that the closely related gorillas and chimpanzees diverged as long as 12 million years ago, four million years earlier than previously thought.

Prior to the find, it was also thought that apes originated in Asia. Before Wednesday, the oldest known ape fossils were eight-million-year-old remains found in Pakistan and China. Previously, no gorillas had been found north of Kenya.

The fossil also represents the first discovery of a great ape in Ethiopia.

However, Ethiopia is home to one of the world's best-known fossil finds. The 3.5-million-year-old Australopithecus afarensis, better known as Lucy, which was discovered in Ethiopia in 1974, is widely acknowledged as one of man's earliest ancestors and one of the most complete ancient fossils ever found.

Since they found only teeth, scientists could not say what this newly discovered gorilla might have looked like. However, paleontologists said they were preparing to embark on an expedition to the region to seek more information.

Their findings will be published in Thursday's edition of the scientific journal Nature.

With files from the Associated Press