When scientists came face to face with China’s Dragon Man fossil for the first time
- Ni Xijun says he knew something was different as soon as he held the skull in his hands
- But another important aspect of their work has been buried by controversy, he says
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As Ni and fellow scientist Ji Qiang at Hebei GEO University began to carefully peel back the layers of plastic around the fossil, Ni’s emotions went from exhilaration to perplexed stillness, he said.
“How could this be? You can say I was shocked but really there was no word I could use to describe how I felt,” said Ni from the Chinese Academy of Sciences.
“How could such a massive skull with such distinctive facial features be so perfectly preserved?
“I just stood there in stillness as I came face to face with it, so captivated that I almost forgot to breathe. It felt like those giant eyes that were once alive were trying to tell me something as I continued to stare at it.”
Ni and Ji were looking at one of the world’s most exquisitely preserved specimens of an archaic human.
Ni said the emotions subsided and “things became full-on technical” for him as soon as he laid hands on the skull for the first time.
“It was very heavy. This human was nothing like what we have studied before. As we got into the anatomical structure, we were able to determine quite early on that it was a mosaic of primitive and derived traits,” he said.
The skull had thick brow ridges, large deep-set eye sockets and flat cheekbones. It would have belonged to a male of no more than 50 with a round fat nose and broad mouth. His brain would have been roughly the same size as that of a modern human.
After months of study, the researchers put the find in a new category of its own Homo longi, or Dragon Man, adding a new branch to humanity’s ancient family tree.
The skull was reportedly unearthed by a bridge construction worker near the Songhua River in Harbin during the Japanese invasion of the country. It was passed by the labourer to another labourer who decided to protect it from the Japanese forces by burying it in a well, where it stayed for 85 years. The labourer divulged the secret shortly before his death and his family exhumed the fossil.
It was eventually donated to Hebei GEO University.
After analysing the chemical composition of the fossil and geological features of the region where it was believed to have been found, the researchers determined that Dragon Man had lived in a densely forested environment at least 146,000 years ago and survived on a diet of fish, mammals, fruit and vegetables.
Ni said that as part of their study, they created a database of more than 600 features from nearly 100 other skull and jawbone specimens and ran more than 3 trillion calculations to plot in the human family tree.
In three peer-reviewed papers published last month, they concluded that the Harbin skull represented a new human species, a separate human lineage in East Asia.
It was a bold move.
“To name a new human species after the Harbin fossil remained quite a controversial issue even within our research team,” Ni said.
Chris Stringer, a physical anthropologist at London’s Natural History Museum and co-author of two of the three papers, agreed that the find warranted a distinct species name but preferred Homo daliensis, grouping the skull with another found in Dali county in the northwest province of Shaanxi in 1978.
“Technically, there are adequate distinctive features to name it a new species as proposed by Ji but Stringer felt it might be too bold of a move,” Ni said.
“I too have struggled between the arguments when penning the papers but we went ahead with naming it a separate species as it actually requires us to make more assumptions about the interactions between different groups of humans that lived in the region if we were to go ahead with a sublineage.
“When it comes to science, the fewer assumptions the better to answer the unresolved problems [of human evolution].”
Other scientists not involved in the studies argued that the Harbin fossil could be Denisovan, an extinct species of archaic human that ranged across Asia. But Ni said this argument remained a speculation, given that only fragments of Denisovan fossils have been found and so no one knew what they looked like.
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Ni said the controversy over the naming had buried another major contribution of their research – the massive database of the human family tree and their mathematical analysis, which they released online.
“I believe this will have a profound impact on future research by offering more scientific and rational approaches to look at the complex evolution of humans,” he said.
“We want to raise more awareness of using modern scientific approaches to solve problems. Those who disagree with us can take a look at our data and do their own analysis. This might result in different conclusions and that would be even better for the advancement of science.”
Ni said the three papers published were preliminary studies of the Harbin fossil and further investigation into the DNA and anatomical structure of the skull would follow.
“We will run more combined analysis with morphological data and molecular data. This is one of our edges that separates us from most other paleoanthropologists,” he said.
But Ni said he was wary of the damage that DNA analysis might inflict on the fossil.
“We wish to keep the fossil intact as much as possible although most molecular biologists would much rather crush the skull to pieces so that they could run as many analyses as possible. I think we will go ahead but we want to ensure minimal damage to its structure,” Ni said.
More geological studies would also have to be done near the Songhua River to narrow down the search area before the team could go into try to find more remains like the Harbin fossil.
“We still have a long way to go in plotting the derived process of human evolution in the past 3 million years,” Ni said.
