Tooth of `Peking Man’ found again after 90 years

It took 90 years but the Museum of Evolution in Uppsala finally located a tooth of `Peking Man’ that had been stored away in a box since it was excavated in China in the 1920s.

Swedish palaeontologists had been digging for fossils with Chinese colleagues from 1914 onwards and a large number of the finds were sent in boxes from China to Sweden for further processing. But some of the boxes were never opened.

Scientists had excavated remains of the heavy-jawed humanoid called Peking Man during the 1920s and 1930s in limestone caves at a place known as Dragon Bone Hill, about 40 kilometres outside Beijing.

Discovery of the skulls, teeth and bones – dated to between 250,000 and 500,000 years ago – amazed the scientists who had been trying for years to find the "missing link" between modern humans and apes as had been postulated in Charles Darwin's theory of evolution.

Back in Uppsala, scientific leader of the Swedish palaeontologists Professor Carl Wiman started documenting the pieces of bone from China and many went on display in the museum that he had built to house them.

But Wiman did not manage to work through all the boxes before he died and his research was discontinued after his death. As a result, 40 big boxes of fossils remained unopened and were stored away.

Staff members started to unpack the boxes in 2011 when Swedish researchers Martin Kundrat, Jan Ove Ebbestad and Per Ahlberg collaborated with representatives from the Beijing Institute of Vertebrate Palaeontology and Palaeoanthropology to examine the contents.

That was when they discovered a canine tooth from Peking Man and finally the analysis has been written up in Acta Anthropologica Sinica, a Chinese journal published by the Institute of Vertebrate Paleontology and Paleoanthropology.

One of the greatest paleontological discoveries of the 20th century was finding the fossils of Peking Man, Homo erectus, in a 500,000-year-old cave in Zhoukoudian near Beijing. The first examples of this pre-human being were two teeth found in the 1920s by Otto Zdansky from Uppsala University. They are now housed in the Museum of Evolution in Uppsala, together with a third tooth discovered later among some fossil material sent to Sweden.

The discovery of Peking Man caused a world sensation. In 1927 the excavation in Zhoukoudian was taken over by Wenhao Weng from China’s Geological Survey and Davidson Black from Canada. Under their guidance, rich material of skulls and other bones were found, but then the entire collection of unique fossils disappeared during the chaos of World War II and has never been retrieved.

"The lost material of Peking Man remains one of the greatest and most painful mysteries for paleontology," Ahlberg said.

The only pieces of Peking Man in Chinese collections today are five teeth and some parts of a skull found in the 1950s and 1960s. The Museum of Evolution has three teeth from the original excavations in the 1920s, and these are regarded as the crown jewels of the collection. These have now been joined by the latest discovered tooth.

Ahlberg, a professor of evolutionary developmental biology at Uppsala, told University World News that the tooth was not only from the Zhoukoudian district, but also from excavations that were undertaken at the beginning of “the classical period” between 1920 and 1930.

“As is well known, almost all material from this excavation period (except the original Uppsala teeth) was lost in 1941, and has never been recovered,” he said. “After the war, Chinese scientists continued to excavate Zhoukoudian and found some new fossils in the deeper layers. But this new tooth is most probably the last fossil from the 'classical’ Peking Man excavations that will ever be found.”

Ahlberg said that with today’s technology, a canine tooth that had not been handled could reveal so much more than in the past, including what the pre-humans ate.

“We can see many details that tell us about the life of the owner of the tooth, which is relatively small, indicating that it belonged to a woman. The tooth is also rather worn, so the person must have been rather old when she died.

“Also, parts of the tooth enamel have been broken off, probably indicating that the person had bitten down on something really hard, like a bone or a nut. We should probably now be talking about a 'Peking Woman’ and not a 'Peking Man’.”

Professor Liu Wu, from the Chinese Academy of Sciences, said the canine tooth was fractured but otherwise well-preserved. “This is an extremely important find. It is the only canine tooth in existence. It can yield important information about how Homo erectus lived in China,” he said.

When the tooth is examined further, looking at possible microscopic mineral granules from plant remains, it may be possible to decide what the pre-human ate. Combining this with other material in the unopened boxes, the scientists hope to be able to reconstruct some of the plant and animal life that existed in ‘Peking Man’s’ environment.

* Peking Man, or Sinanthropus pekinensis, was not a single individual, but a species of Homo erectus who were very similar to modern humans, having a large brain, and similar skull and bone sizes. They had heavy brows and large, chinless jaws and lived between 750,000 and 200,000 years ago.