Researchers have found fossilized teeth of the gorilla dating to 10 million years ago and which is supposed to be the earliest ever discovered. The new species (Chororapithecus abyssinicus) from Ethiopia, reported on ‘A new species of great ape from the late Miocene epoch in Ethiopia’, helps to fill in a huge gap in the fossil record. The last common ancestor of humans and gorillas might have lived at least 2 million years earlier than previously thought, have been found in Africa.
Ethiopian and Japanese researchers who were in the team have based its conclusion on just nine teeth from at least three individuals of the species, which were discovered in the desert scrubland of Afar about 170 kilometres east of Addis Ababa.
Gen Suwa of the University of Tokyo Museum, Japan, who led the study says the teeth, eight molars and a canine, are collectively indistinguishable from modern gorilla subspecies in size, proportion and scan-revealed internal structure. The team argues that the divergence date of gorilla’s from the human lineage is not about 8 million years ago as previously surmised (S. Kumar et al. Proc. Natl Acad. Sci. USA102, 18842–18847; 2005), but on the basis of the age of the new species it is “greater than 10 to 11 million years ago”.
This new discovery could prompt discussions on the divergence of hominin lines from chimps, previously pegged at about 6 million years ago. According to Suwa some researchers have argued that “Chororapithecus abyssinicus suggests, once again, that Africa was the place of origin of both humans and modern African apes not Eurasia.”
But Jay Kelley a palaeoanthropologist, who was not involved in the study, says more fossils, analysis and debate will be needed to determine whether the specimen is ancestral to hominids. For now, he would be “very cautious” about using the specimen to realign divergence dates between hominins and gorillas–chimps.