An inconvenient fossil
In 2007, a team of paleoanthropologists announced a discovery from the Chorora Formation in Ethiopia's Afar region: nine fossil teeth. The teeth belonged to a previously unknown extinct ape, which they named Chororapithecus abyssinicus. "Chorora" refers to the geological formation where they were found, and "abyssinicus" references Abyssinia, the former name of Ethiopia. The fossils—eight molars and one canine—were found at the Beticha locality and belonged to at least three different individuals.
Initial analysis showed the teeth were remarkably similar in size and shape to those of modern gorillas. The molars possessed the high shearing crests adapted for a diet of fibrous vegetation, like stems and leaves, which is characteristic of gorillas. Based on these features, the researchers proposed that Chororapithecus was an early member of the gorilla lineage (tribe Gorillini). The discovery was significant because, at the time, the fossil record for great apes in Africa between 12 and 8 million years ago was almost completely empty. This gap led some scientists to hypothesize that the ancestors of modern African apes had evolved in Eurasia—where many ape fossils from that period are found—and later migrated back to Africa. Chororapithecus provided direct fossil evidence of a great ape lineage living in Africa during this period.