240,000-Year-Old Teeth Discovered in China Hint at Previously Unknown Human Ancestor

In the 1970s researchers discovered a set of ancient teeth in China, which they believe originated around 240,000 years ago

Now, under the suspicion they could reveal a previously unknown human ancestor, scientists are taking a closer look at the specimens.

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The four teeth were discovered in the Yanhui Cave, located in Southern China’s Tongzi county, between 1972 and 1983.

Scientists quickly classified the teeth as belonging to Homo erectus, a human ancestor that walked upright dating back 1,8 million years ago.

However, a group of experts from Spain, members of the Centro Nacional de Investigacion Sobre la Evolucion Humana (CENIEH) argue that the intricate set of teeth may have originated from three possible hominids: Hom Erectus, Neanderthals, or possibly a third hybrid, and unknown human ancestor.

Using geometric morphometrical analysis which helps examine the change of shape, Micro-Computed Tomography, as well as 3D imaging, the researchers came to the conclusion we could be looking at an entirely new species of humans.

The experts revealed the teeth originated between 170,000 and 240,000 years ago.

Part of their study involved comparing the teeth to teeth belonging to the same chronological period.

After looking at several comparative samples, scientists were unable to say exactly to what species the teeth belonged to.

As noted by National Geographic, to find out more about the teeth, and pinpoint their origin, scientists analyzed the structure and patterns of the teeth. The samples were also compared to modern-day teeth originating from East Asia, and other regions like West Asia, Africa, and the European Continent.

After comparing the samples, the mystery got even bigger as they discovered that the dentine, didn’t appear to have the same crinkles found in Homo erectus, notes National Geographic.

The researchers instead found that the teeth had much simpler features akin to those found in Neanderthals, but they still weren’t a perfect match. Scientists from CENIEH argue that one explanation may be found if we look at the Denisovans, a mysterious human ancestor that split from the Neanderthals more than 400,000 years ago.

Image Credit: S. Xing.
Image Credit: S. Xing.

But just as the teeth had features akin to Neanderthals, scientists found the teeth had various similarities to Denisovans.

However, they explain that the denture was not located in the same place in the mouth, making it extremely difficult to come to a satisfactory conclusion.

“An abundant amount of genetic information has been collected from the Denisovans but there are very few fossils remains,” researchers from CENIEH explained.

“Therefore, both their physical appearance and their identification in the fossil record remain a mystery,” experts added.

But one of the more satisfactory explanations that may explain the mysterious origin of the teeth is a third, previously unknown human species that existed more than 240,000 years ago.

“More genetic and fossil discoveries would be necessary to evaluate the taxonomy of the non-Erectus populations of the Middle Pleistocene, such as the Tongzi hominids, which could be good candidates for the Denisovan ancestry,” explained Maria Martinon-Torres, one of the co-authors of the study.

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National Geographic / Ancient teeth hint at mysterious human relative