Tuesday, April 2, 2024

Homo Longi Might Be Denisovans

A March 30, 2024 report in the Guardian, a British newspaper, reports that scientists have linked bones classified as Homo Longi in China to the Denisovan archaic hominin species which is known by its genetics but has left very few fossil remains. DNA found in context with the Chinese fossils and proteins in the fossils which don't have surviving DNA themselves, support the Homo Longi - Denisovan connection. 

Denisovans are a sister species to Neanderthals and modern humans who overlapped temporally and geographically with both, since modern humans outside of Africa have some Neanderthal admixture, and many humans in Asia and Oceania have Denisovan admixture (with Papuans, Aboriginal Australians and negrito people from the Philippines having the most Denisovan admixture).

This article seems to be associated with a recent journal publication. If anyone can find it, please post relevant information in the comments.

An artist's reconstruction of the Homo Longi individual is shown below:

[R]ecently scientists have pinpointed a strong candidate for the species to which the Denisovans might have belonged. This is Homo longi – or “Dragon man” – from Harbin in north-east China. This key fossil is made up of an almost complete skull with a braincase as big as a modern human’s and a flat face with delicate cheekbones. Dating suggests it is at least 150,000 years old.

“We now believe that the Denisovans were members of the Homo longi species,” said Prof Xijun Ni of the Chinese Academy of Sciences in Beijing, last week. “The latter is ­characterised by a broad nose, thick brow ridges over its eyes and large tooth sockets.” . . .
In addition, evidence to ­support the Denisovan-Homo longi link has also been traced to the Tibetan ­plateau, where scientists began studying a jawbone initially found in a remote cave 3,000 metres (10,000ft) above sea level by a Buddhist monk, who kept it as a relic.

The bone was found not to come from a modern human. But only when researchers began to study the cave where the jawbone had been originally discovered did they find its ­sediments were rich in Denisovan DNA. In addition, it was found the fossil itself contained proteins that indicated Denisovan origins.

“It was the first time a Denisovan fossil find had been made outside Sibera and that was very important,” said Janet Kelso of the Max Planck Institute of Evolutionary Anthropology in Leipzig, Germany. “Equally intriguing was the fact that the jawbone has teeth that are similar to the teeth found in Homo longi. So I think the evidence suggests a link between the cranium and Denisovans”

This view was backed by Prof Chris Stringer of the Natural History Museum in London. “The evidence supports the idea that Denisovans were members of Homo longi but we are still short of absolute proof. Nevertheless, that will come with time, I believe.”

A big problem for researchers has been the fact that no DNA has yet been found in Chinese fossils such as Homo longi, added Stringer. “Their genes have not survived the ­passing of time. However, using the ­techniques of proteomics may ­provide key new data. These focus on a fossil’s ­proteins, which survive for far longer than its DNA and could tell us much more about the species.”

No comments: