A complete evaluation of an unusually massive cranium present in Harbin, China has led to the reported discovery of a beforehand unknown species of extinct human, dubbed “Dragon Man.” Relationship again some 146,000 years, the cranium is forcing a re-think of human evolution in Asia throughout the Center Pleistocene, however uncertainties concerning the fossil’s precise age are casting doubt on the findings.
“Personally, I feel the Harbin fossil is without doubt one of the most essential finds to date for the final 500,000 years of human evolution,” Chris Stringer, an anthropologist on the Pure Historical past Museum of London and a contributing member of the investigating crew, mentioned in an e mail.
Certainly, the invention of Homo longi, or Dragon Man, suggests a 3rd human lineage was current in Eurasia throughout the Late Center Pleistocene, along with Homo sapiens and Neanderthals. The mysterious Denisovans had been additionally round right now, however they belong to the Neanderthal lineage. The discovering suggests every of the three lineages skilled their very own evolutionary journeys, and that Asia was an essential area for human evolution, in line with Stringer. Particulars of this discovery had been revealed in the present day in three associated papers, all revealed in The Innovation, a peer-reviewed scientific journal from Cell Press.
The exquisitely preserved Harbin skull is the most important human cranium ever discovered, that includes an array of distinct options that set it aside from each trendy people and Neanderthals. In accordance with the analysis, H. longi is extra intently associated to trendy people than to Neanderthals, which suggests it’s the true sister group to the Homo sapiens lineage, not Neanderthals.
Properly, assuming this interpretation is appropriate. The findings are fascinating and clearly essential, however the researchers have ventured into rocky territory, because the fossil was discovered outdoors of its unique context, making it troublesome to precisely supply and date the specimen.
Cranium in a effectively
The cranium was present in Harbin Metropolis of China’s Heilongjiang province again within the 1930s, however due to the Second World Battle, the Chinese language Communist Revolution, “and plenty of different issues” having to do with the item’s lengthy and complex historical past, the household who discovered the cranium hid it in a effectively, the place it languished for the previous 85 years, in line with Xijun Ni, a co-author on all three papers and a paleoanthropologist on the Chinese language Academy of Sciences. The household, now three generations later, donated the cranium to a public museum in 2018, making the skull “identified to the world,” and permitting scientists to lastly research the outstanding specimen, as Ni defined.
After acquiring the cranium, Qiang Ji, a professor of paleontology of Hebei GEO College, assembled a crew to investigate it. Stringer was requested to take part, and the crew spent the subsequent 18 months engaged on descriptions, comparisons, analyses, and preparations of the three papers. Every paper focuses on a specific ingredient of the analysis, particularly the dating of the specimen, the identification of a new species of Homo, and the updated evolutionary family tree, or phylogenetic evaluation.
“I’ve lengthy suspected that there was a definite species of human in East Asia, and I used to be delighted to be invited to review this splendidly preserved fossil that validated the concept,” mentioned Stringer.
The primary problem was up to now the fossil with no stratigraphic context. Ideally, the sediment wherein an object is discovered is dated, however that was not doable on this case, as the precise spot from which this cranium was sourced is just not identified. As for radiocarbon courting, that solely works for samples youthful than 50,000 years previous, which meant the crew needed to depend on geochemical courting methods, specifically non-destructive X-ray radiation fluorescence, a uncommon earth ingredient evaluation, Uranium-series courting, and a strontium isotopic evaluation.
Information gleaned from these methods had been then in comparison with sediments and mammalian fossils sourced within the Harbin space. This resulted in a fairly vast age constraint for the cranium, with the newest doable date at 146,000 years previous and the oldest at 309,000 years previous. That’s a span of 163,000 years, which isn’t insignificant.
Kira Westaway, a geochronologist at Macquarie College in Australia who wasn’t a part of the brand new analysis, mentioned the worth of the fossil is “indeniable,” however its “significance is tougher to ascertain” provided that the precise origin of the specimen is unknown.
“Homo longi, or ‘Dragon man,’ actually has an inviting identify and a particularly convoluted historical past, which sadly implies that it enters the ranks of attention-grabbing fossils with no safe provenance,” she wrote in an e mail. “The authors have made admirable makes an attempt to patch collectively doable areas and potential stratigraphic layers from which it was discovered, however the precise provenance nonetheless stays unknown.”
To which she added: “If the provenance is required to safe the courting, then they’ll’t use the courting to ascertain the provenance. When coping with human evolution, uncertainty tends to breed doubt. The authors have underestimated the worth of provenance and age when making wide-ranging interpretations of the place the hominin sits within the household tree.”
Ni mentioned it’s “unlucky that the skull misplaced its stratigraphic info,” however he’s wanting ahead to “new applied sciences for getting much more exact provenance and age.”
A brand new species of Homo
That H. longi represents a beforehand unknown Homo species is much less controversial. The cranium, undistorted and almost full, belonged to a person who died across the age of 50. No DNA could possibly be extracted from the skull, forcing the scientists to depend on a bodily examination.
Dragon Man had an infinite cranium, however the mind it as soon as held was related in dimension to that of our personal species. In comparison with us, H. longi had bigger, squarish eye sockets, thick forehead ridges, a large mouth, an expanded nasal area, flat and low cheekbones, and enlarged tooth (particularly the molars). Dragon Man was “huge in dimension,” because the researchers wrote, and in addition fairly totally different from Neanderthals. Taken collectively, these variations had been sufficient to warrant the declaration of a completely new species inside the Homo department.
Stringer mentioned these people had been possible hunter-gatherers.
“From the winter temperatures in Harbin in the present day, it appears like they had been dealing with even harsher chilly than the Neanderthals,” he mentioned. “This most likely required each bodily and cultural diversifications, however we are able to’t say greater than that for the time being, as we don’t have archaeological materials related to the Harbin fossil.”
A surprisingly shut relative
With the brand new species established, the researchers then went concerning the enterprise of reconstructing the human household tree. Fashionable people and Neanderthals are descended from a typical ancestor, however the brand new analysis suggests trendy people and the Harbin people branched off from a typical ancestor extra lately.
“We carried out a complete research of the exterior morphology of the skull, utilizing over 600 traits, and we then used a really highly effective pc to construct timber of relatedness to different fossils,” mentioned Stringer. “After many thousands and thousands of tree-building processes, we arrived on the most parsimonious timber. These recommend that Harbin and another fossils from China kind a 3rd lineage of later people alongside the Neanderthals and H. sapiens.”
Stringer mentioned he was shocked by the phylogeny, wherein H. sapiens had been proven to be extra intently linked to H. longi than to Neanderthals, however that’s what the info confirmed. Ni agreed, saying it’s “statistically probably to imagine that the Homo longi lineage is the sister group of Homo sapiens lineage” based mostly on their outcomes. “The 2 lineages share the newest widespread ancestor,” Ni added, whereas Neanderthals share a typical ancestor with these two lineages that dates additional again in time.
The scientists plan to make all their information publicly obtainable, which suggests their up to date household tree may be examined and evaluated by different teams. Stringer mentioned the phylogenetic tree is “not sure” and that it features as a speculation for testing. Trying forward, the crew will now characterize the inside form of the Harbin skull in additional element.
Extra proof, each archaeological and paleontological, might be required to strengthen the case, however the obvious existence of Dragon Man now raises some fascinating questions. Simply how large had been these historic people, the place and when did they reside, and why did they ultimately go extinct? And the large query: Did they encounter and interbreed with trendy people? This can be a tantalizing chance, as analysis from 2019 suggests the presence of a lacking ancestor in our DNA.
The human origin story, as difficult as it’s, continues to unfold.
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