Dental records show westward shift in early human evolution
An upper molar is the first piece of evidence that shows nearly 2 million years ago, early hominins occupied the western part of Central Africa - the cradle of human evolution.
The findings branch off of a discovery made in the 1950s, when anthropologists unearthed a tooth in Central Africa. At that time, the technology to identify the age of the tooth did not exist. And it wasn't until 2014 when a team of researchers, including an anthropologist from New York University, put a rough number on how old it really was.
This tooth, an upper molar from a young individual, was found in a layer of sediment dating back to the Plio-Pleistocene, about 2.6 to 1.8 million years ago. Talk about ancient bad breath.
Analysis revealed a fascinating consistency in dental enamel thickness and dimensions with molars of early east and southern African hominins, which are classified as a tribe of primates that share defining qualities with human beings, such as walking on two feet and increased brain size.
Until this point, it was believed that early humans stayed in the eastern branch of Central Africa. The results, which were published in the journal PLOS ONE, expanded the range of early hominins significantly farther west, revealing a need for a shift in the search for early hominins.
"While the eastern branch of the Rift Valley is an important place for early human evolution, this find suggests additional results may come from farther west than we once thought," NYU anthropologist Shara Bailey said in a press release.
The East African Rift system runs southward through eastern Africa and consists of two main branches: the main eastern Gregory Rift and the smaller, western Albertine Rift. The larger section is considered the cradle of human evolution, containing sites where hundreds of early hominin fossils have been discovered. Though part of the same system, no discoveries had been in the western Albertine branch.
The dental record lends itself to a refined understanding of early hominin evolution, suggesting that they in fact dispersed to new regions beyond east and south Africa. It also underpins how modern techniques can shed light on old samples, in this case a 60-year-old find. From here on out, researchers might need to keep an eye on hominin halitosis.