Fossil evidence suggests humans, gorillas split as far back as 10 million years ago
Researchers say the new evidence also suggests early man originated in Africa and not Eurasia, as some believe.
Their findings suggest that the fossilized teeth represent the oldest mammalian fossils found south of the Sahara desert area, which, the team claims, adds credence to the theory that apes and thus humans originated in Africa, not Eurasia as some have claimed.
'Since few great ape fossils have been found in Africa so far, some scientists have forcefully suggested that the ancestors of African apes and humans must have emerged in Eurasia,' said senior author Gen Suwa, a paleoanthropologist at the University of Tokyo.
Researchers are hopeful that these findings could help resolve the controversy of where and when the human lineage first evolved.
'The palaeobiological record of 12 million to 7 million years ago is crucial to the elucidation of African ape and human origins, but few fossil assemblages of this period have been reported from sub-Saharan Africa,' reads the study published in the journal Nature.
The strongest evidence they have is that genetics reveal a common lineage between great apes and humans, which has pushed researchers to find clues about when the separation actually occurred.
If looking at genetics, it suggest humans split from chimps as early as 5 million years ago and with gorillas about 7 to 8 million years ago.
But archaeologists have been puzzled by these numbers, because these dates do not match their findings.
Suwa and his team returned focused on the Chorora Formation, the oldest sediments from the Afar rift on record, because it has produced evidences of some of the earliest known hominins – human and related species dating back to the split.
In 2007, the team discovered nine fossil that belonged to an extinct species of gorilla they called Chororapithecus abyssinicus.
'They exhibit a gorilla-sized dentition that combines distinct shearing crests with thick enamel on its ‘functional’ side cusps,' Suwa wrote about the first discovery of the teeth in 2007 published in the journal Nature.
Visualization of the enamel–dentine junction by micro-computed tomography reveals shearing crest features that partly resemble the modern gorilla condition.'
Suwa and his colleagues analyzed the surrounding volcanic rock and once-magnetized particles of the sediment above and below fossils from the Chorora Formation and dated that Chororapithecus probably roamed the earth 8 million years ago.
'Until now, no mammalian fossils south of the Sahara have been securely date to 8 million to 9 million years ago,' said Suwa.
'Any and all fossils from this crucial time period of Africa would help unravel the story of human origins and emergence. These are the first such fossils.'
Because Chororapithecus is suggested to be 8 million years old, researchers say 'the actual gorilla-human split must have been up to several million years before that.'
Author: Stacy Liberatore | Source: Dailymail [February 12, 2016]