Latest news with #fossils
Yahoo
20 hours ago
- Science
- Yahoo
The Rocks Beneath Your Feet Are Younger Than Your Parents and Made of Your Trash
Here's what you'll learn when you read this story: The rock cycle naturally takes thousands to millions of years, but scientists just identified a new form of rock that cements in under four decades. Researchers believe the natural cements found in industrial waste react with the ocean, leading to rapid cementation. Experts were able to estimate the cementation timeline using modern objects found in the rock, some of which include a zipper, a King Charles V coin, and a soda tab. Fossils are amazing; not only can they spark inspiration for iconic movie franchises (I'm looking at you, Jurassic Park), but they more importantly also provide accurate timestamps that help researchers piece together history from across millennia. Incredibly, scientists are starting to find examples of a new kind of fossil—well, sort of. Researchers from the University of Glasgow found modern society's detritus, including things like soda tabs, cemented inside a new form of rock. Published in the journal Geology, the study reconsiders everything we know about the rock cycle and how humans affect it. Typically, rocks take thousands to millions of years to form, with processes like heating, compaction, and melting producing different types of rock over long periods of time. The recent study, however, found that the anthropoclastic rock cycle is forming rocks in just 35 years rather than hundreds. Researchers realized this when they were studying slag deposits—or byproducts from industrial production—at Derwent Howe in West Cumbria. The region was formerly home to steel and iron-making plants, and scientists noticed irregular formations in the coastal cliffs, leading them to investigate 13 different sites in the area. Using methods including electron microscopy, X-ray diffraction, and Raman spectroscopy (chemical analysis), the team determined the slag is made of 'natural cements' like calcite, goethite, and brucite. They explain in the study that the rapid cementation is likely a reaction between the waste and the sea water. Researchers were able to pinpoint just how rapid this new rock formation is by using the 'anthropogenic material'—or, more simply put, modern junk—they found hiding inside the rock. 'We found both a King George V coin from 1934 and an aluminium can tab with a design that we realised couldn't have been manufactured before 1989 embedded in the material,' John MacDonald, co-author of the study, explained in a press release. 'This gives us a maximum time frame of 35 years for this rock formation, well within the course of a single human lifetime.' Other discoveries include a zipper, copper wire, and even a tire. 'This is an example in microcosm of how all the activity we're undertaking at the Earth's surface will eventually end up in the geological record as rock,' MacDonald continued, 'but this process is happening with remarkable, unprecedented speed.' Researchers also expressed the environmental concerns the new rock form poses. The study suggests that we don't have as much time to dispose of loose waste material as we previously believed—and it only gets worse after it hardens. According to experts, excess anthropoclastic rocks could affect life both above and below the water's surface, especially as coastal ecosystems change with rising sea levels. 'What's remarkable here is that we've found these human-made materials being incorporated into natural systems and becoming lithified—essentially turning into rock—over the course of decades instead,' co-author Amanda Owen said in the release. 'It challenges our understanding of how a rock is formed, and suggests that the waste material we've produced in creating the modern world is going to have an irreversible impact on our future.' While this isn't the first time the anthropoclastic rock cycle was recorded, it is the first time researchers could put a definitive timeline on the process. The team explained in the release that the effects of anthropoclastic rock aren't currently included in models of erosion and land management, which are crucial parts of combating climate change. In the future, the researchers hope to study more deposits throughout Europe and further understand the rapid anthropoclastic rock cycle. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
CNN
20 hours ago
- Science
- CNN
‘Dragon Man' DNA revelation puts a face to a mysterious group of ancient humans
Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. CNN — An enigmatic skull recovered from the bottom of a well in northeastern China in 2018 sparked intrigue when it didn't match any previously known species of prehistoric human. Now, scientists say they have found evidence of where the fossil fits, and it could be a key piece in another cryptic evolutionary puzzle. After several failed attempts, the researchers managed to extract genetic material from the fossilized cranium — nicknamed Dragon Man — linking it to an enigmatic group of early humans known as Denisovans. A dozen or so Denisovan fossilized bone fragments had previously been found and identified using ancient DNA. But the specimens' small size offered little idea of what this shadowy population of ancient hominins looked like, and the group has never been assigned an official scientific name. Scientists typically consider skulls, with telltale bumps and ridges, the best type of fossilized remains to understand the form or appearance of an extinct hominin species. The new findings, if confirmed, could effectively put a face to the Denisovan name. 'I really feel that we have cleared up some of the mystery surrounding this population,' said Qiaomei Fu, a professor at the Institute of Paleontology and Paleoanthropology, part of the Chinese Academy of Sciences in Beijing, and lead author of the new research. 'After 15 years, we know the first Denisovan skull.' Denisovans were first discovered in 2010 by a team that included Fu — who was then a young researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany — from ancient DNA contained in a pinkie fossil found in Denisova Cave in the Altai Mountains of Russia. Additional remains unearthed in the cave, from which the group gets its name, and elsewhere in Asia continue to add to the still-incomplete picture. The new research, described in two scientific papers published Wednesday, is 'definitely going to be among, if not the, biggest paleoanthropology papers of the year,' and will spur debate in the field 'for quite some time,' said Ryan McRae, a paleoanthropologist at the Smithsonian National Museum of Natural History in Washington, DC, who was not involved in the studies. The findings could help fill in gaps about a time when Homo sapiens weren't the only humans roaming the planet — and teach scientists more about modern humans. Our species once coexisted for tens of thousands of years and interbred with both Denisovans and Neanderthals before the two went extinct. Most humans today carry a genetic legacy of those ancient encounters. Neanderthal fossils have been the subject of study for than a century, but scant details are known about our mysterious Denisovan cousins, and a skull fossil can reveal a great deal. Long in the tooth A laborer in the city of Harbin in northeastern China discovered the Dragon Man skull in 1933. The man, who was constructing a bridge over the Songhua River when that part of the country was under Japanese occupation, took home the specimen and stored it at the bottom of a well for safekeeping. The man never retrieved his treasure, and the cranium, with one tooth still attached in the upper jaw, remained unknown to science for decades until his relatives learned about it before his death. His family donated the fossil to Hebei GEO University, and researchers first described it in a set of studies published in 2021 that found the skull to be at least 146,000 years old. The researchers argued that the fossil merited a new species name given the unique nature of the skull, naming it Homo longi — which is derived from Heilongjiang, or Black Dragon River, the province where the cranium was found. Some experts at the time hypothesized that the skull might be Denisovan, while others have lumped the cranium in with a cache of difficult-to-classify fossils found in China, resulting in intense debate and making molecular data from the fossil particularly valuable. Given the skull's age and backstory, Fu said she knew it would be challenging to extract ancient DNA from the fossil to better understand where it fit in the human family tree. 'There are only bones from 4 sites over 100,000 (years old) in the world that have ancient DNA,' she noted via email. Fu and her colleagues attempted to retrieve ancient DNA from six samples taken from Dragon Man's surviving tooth and the cranium's petrous bone, a dense piece at the base of the skull that's often a rich source of DNA in fossils, without success. The team also tried to retrieve genetic material from the skull's dental calculus — the gunk left on teeth that can over time form a hard layer and preserve DNA from the mouth. From this process, the researchers managed to recover mitochondrial DNA, which is less detailed than nuclear DNA but revealed a link between the sample and the known Denisovan genome, according to one new paper published in the journal Cell. 'Mitochondrial DNA is only a small portion of the total genome but can tell us a lot. The limitations lie in its relatively small size compared to nuclear DNA and in the fact that it is only inherited from the matrilineal side, not both biological parents,' McRae said. 'Therefore, without nuclear DNA a case could be made that this individual is a hybrid with a Denisovan mother, but I think that scenario is rather less likely than this fossil belonging to a full Denisovan,' he added. Mounting evidence The team additionally recovered protein fragments from the petrous bone samples, the analysis of which also suggested the Dragon Man skull belonged to a Denisovan population, according to a separate paper published Wednesday in the journal Science. Together, 'these papers increase the impact of establishing the Harbin cranium as a Denisovan,' Fu said. The molecular data provided by the two papers is potentially very important, said anthropologist Chris Stringer, research leader in human origins at London's Natural History Museum. 'I have been collaborating with Chinese scientists on new morphological analyses of human fossils, including Harbin,' he said. 'Combined with our studies, this work makes it increasingly likely that Harbin is the most complete fossil of a Denisovan found so far.' However, Xijun Ni, a professor at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing who, along with Stringer, worked on the initial Dragon Man research but not the latest studies, said that he is cautious about the outcome of the two papers because some of the DNA extraction methods used were 'experimental.' Ni also said he finds it strange that DNA was obtained from surface dental calculus but not inside the tooth and petrous bone, given that the calculus appeared to be more exposed to potential contamination. Nonetheless, he added that he thinks it is likely the skull and other fossils identified as Denisovan are from the same human species. The goal in using a new extraction approach was to recover as much genetic material as possible, Fu explained, adding that the dense crystalline structure of dental calculus may help prevent the host DNA from being lost. The protein signatures Fu and her team recovered indicated 'a Denisovan attribution, with other attributions very unlikely,' said Frido Welker, an associate professor of biomolecular paleoanthropology at the University of Copenhagen's Globe Institute in Denmark. Welker has recovered Denisovan proteins from other candidate fossils but was not involved in this research. 'With the Harbin cranium now linked to Denisovans based on molecular evidence, a larger portion of the hominin fossil record can be compared reliably to a known Denisovan specimen based on morphology,' he said. A name and a face for Denisovans With the Dragon Man skull now linked to Denisovans based on molecular evidence, it will be easier for paleoanthropologists to classify other potential Denisovan remains from China and elsewhere. McRae, Ni and Stringer all said they thought it was likely that Homo longi would become the official species name for Denisovans, although other names have been proposed. 'Renaming the entire suite of Denisovan evidence as Homo longi is a bit of a step, but one that has good standing since the scientific name Homo longi was technically the first to be, now, tied to Denisovan fossils,' McRae said. However, he added that he doubts the informal name of Denisovan is going anywhere anytime soon, suggesting it might become shorthand for the species, as Neanderthal is to Homo neanderthalensis. The findings also make it possible to say a little more about what Denisovans might have looked like, assuming the Dragon Man skull belonged to a typical individual. According to McRae, the ancient human would have had very strong brow ridges, brains 'on par in size to Neanderthals and modern humans' but larger teeth than both cousins. Overall, Denisovans would have had a blocky and robust-looking appearance. 'As with the famous image of a Neanderthal dressed in modern attire, they would most likely still be recognizable as 'human,'' McRae said. 'They are still our more mysterious cousin, just slightly less so than before,' he added. 'There is still a lot of work to be done to figure out exactly who the Denisovans were and how they are related to us and other hominins.'
Sustainability Times
2 days ago
- Science
- Sustainability Times
'I Seen Predatory Horse With Razor Teeth': Scientists Unveil 86-Million-Year-Old T. Rex Ancestor That Redefines Dinosaur Evolution
IN A NUTSHELL 🦖 Khankhuuluu mongoliensis is an 86-million-year-old dinosaur species discovered in Mongolia, providing new insights into tyrannosaur evolution. is an 86-million-year-old dinosaur species discovered in Mongolia, providing new insights into tyrannosaur evolution. 📜 The fossils fill a crucial gap in the evolutionary timeline, linking smaller ancestors to the giant Tyrannosaurus rex . . 🐎 This medium-sized predator, roughly the size of a horse, relied on speed and agility rather than bone-crunching power. 🔍 The study, led by researchers at the University of Calgary, highlights the dynamic evolution of tyrannosaurs over millions of years. In a remarkable discovery, paleontologists have unearthed a new piece in the evolutionary puzzle of the Tyrannosaurus rex. A recent study has brought to light a medium-sized predator that roamed the Earth 86 million years ago, offering fresh insights into the lineage of these iconic dinosaurs. This creature, identified from fossils found in Mongolia, fills a crucial gap in our understanding of how the mighty T. rex evolved from its smaller ancestors. The species, named Khankhuuluu mongoliensis, or 'the dragon prince,' provides a fascinating glimpse into the past, allowing us to trace the fascinating journey from small predators to the apex predators we know today. The Discovery of Khankhuuluu Mongoliensis The discovery of Khankhuuluu mongoliensis marks a significant milestone in paleontological research. Originally unearthed in the 1970s in the Bayanshiree Formation of southeastern Mongolia, these fossils were initially misclassified. It wasn't until researchers Jared Voris and Dr. Darla Zelenitsky from the University of Calgary revisited the site in 2023 that the true nature of these fossils was uncovered. The team noted the distinctive features of the remains, particularly the hollow snout bone, which pointed clearly to an early member of the tyrannosaur family. This species, roughly the size of a horse, weighed around 1,653 pounds and measured 13 feet in length. Its discovery provides a new understanding of the evolutionary sequence leading to the Tyrant Lizard King, the T. rex. The name Khankhuuluu, translating to 'the dragon prince,' is a nod to its role as a precursor to one of the most iconic predators in history. This Prehistoric Armored Fish From 465 Million Years Ago Could Be the Key to Understanding Why Our Teeth Still Hurt The Missing Evolutionary Gap For years, the evolutionary path of tyrannosaurs from small creatures to the colossal T. rex remained a mystery, with significant gaps in the fossil record. These dinosaurs began their journey around 150 million years ago during the Jurassic period as modest-sized tyrannosaurids. It was only in the late Cretaceous period that they grew into the giants we are familiar with today. The newly identified fossils of Khankhuuluu mongoliensis are crucial in filling this gap. They offer a rare glimpse into a transitional phase, illustrating how these dinosaurs evolved from smaller predators to become the dominant force in their ecosystems. The discovery of these fossils not only enhances our understanding of tyrannosaur evolution but also highlights the dynamic changes that occurred during their ascent to dominance. '8,000 Dinosaur Bones Found': Canada's Fossil Graveyard Reveals One of the Most Terrifying Prehistoric Mass Death Sites Ever Unearthed Physical Characteristics and Lifestyle Khankhuuluu mongoliensis, with its lean build and significant size, was an adept hunter. Unlike its massive descendants, this species had a long, shallow skull, indicating it lacked the ability to crunch bones like the T. rex. Instead, it relied on speed and agility, similar to modern-day mesopredators like coyotes, to hunt and capture prey. The presence of tiny, rudimentary horns on its head suggests that these features might have played a role in mating rituals or intimidation displays. Over time, these features evolved into the more prominent horns seen in later tyrannosaurs such as Albertosaurus. The creature's unique combination of features underscores the diversity and adaptability of the tyrannosaur lineage, providing a deeper understanding of the evolutionary pressures that shaped these formidable predators. 'This Thing Shouldn't Exist': Scientists Stunned as Humanity Witnesses This Deep-Sea Monster Alive for the First Time Ever Implications for Tyrannosaur Research The discovery of Khankhuuluu mongoliensis has profound implications for the study of tyrannosaurs. By bridging a critical gap in the fossil record, it allows scientists to trace the evolutionary trajectory of these dinosaurs with greater accuracy. This newfound knowledge not only enriches our understanding of tyrannosaur evolution but also offers broader insights into the ecological dynamics of prehistoric times. Researchers continue to study the fossils to uncover more about the lifestyle and environment of this fascinating creature. The ongoing analysis of its physical characteristics and the ecological context in which it lived promises to shed light on the evolutionary adaptations that enabled tyrannosaurs to thrive and diversify into some of the largest land predators in history. The discovery of Khankhuuluu mongoliensis opens new avenues for research and invites us to ponder the incredible journey of evolution. As we continue to uncover the mysteries of these ancient creatures, what other secrets might the past hold about the rise of the world's most fearsome predators? Our author used artificial intelligence to enhance this article. Did you like it? 4.5/5 (21)
CNN
2 days ago
- Science
- CNN
A skull found in a well defied classification. Now it could help unravel an evolutionary mystery
An enigmatic skull recovered from the bottom of a well in northeastern China in 2018 sparked intrigue when it didn't match any previously known species of prehistoric human. Now, scientists say they have found evidence of where the fossil fits, and it could be a key piece in another cryptic evolutionary puzzle. After several failed attempts, the researchers managed to extract genetic material from the fossilized cranium — nicknamed Dragon Man — linking it to an enigmatic group of early humans known as Denisovans. A dozen or so Denisovan fossilized bone fragments had previously been found and identified using ancient DNA. But the specimens' small size offered little idea of what this shadowy population of ancient hominins looked like, and the group has never been assigned an official scientific name. Scientists typically consider skulls, with telltale bumps and ridges, the best type of fossilized remains to understand the form or appearance of an extinct hominin species. The new findings, if confirmed, could effectively put a face to the Denisovan name. 'I really feel that we have cleared up some of the mystery surrounding this population,' said Qiaomei Fu, a professor at the Institute of Paleontology and Paleoanthropology, part of the Chinese Academy of Sciences in Beijing, and lead author of the new research. 'After 15 years, we know the first Denisovan skull.' Denisovans were first discovered in 2010 by a team that included Fu — who was then a young researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany — from ancient DNA contained in a pinkie fossil found in Denisova Cave in the Altai Mountains of Russia. Additional remains unearthed in the cave, from which the group gets its name, and elsewhere in Asia continue to add to the still-incomplete picture. The new research, described in two scientific papers published Wednesday, is 'definitely going to be among, if not the, biggest paleoanthropology papers of the year,' and will spur debate in the field 'for quite some time,' said Ryan McRae, a paleoanthropologist at the Smithsonian National Museum of Natural History in Washington, DC, who was not involved in the studies. The findings could help fill in gaps about a time when Homo sapiens weren't the only humans roaming the planet — and teach scientists more about modern humans. Our species once coexisted for tens of thousands of years and interbred with both Denisovans and Neanderthals before the two went extinct. Most humans today carry a genetic legacy of those ancient encounters. Neanderthal fossils have been the subject of study for than a century, but scant details are known about our mysterious Denisovan cousins, and a skull fossil can reveal a great deal. A laborer in the city of Harbin in northeastern China discovered the Dragon Man skull in 1933. The man, who was constructing a bridge over the Songhua River when that part of the country was under Japanese occupation, took home the specimen and stored it at the bottom of a well for safekeeping. The man never retrieved his treasure, and the cranium, with one tooth still attached in the upper jaw, remained unknown to science for decades until his relatives learned about it before his death. His family donated the fossil to Hebei GEO University, and researchers first described it in a set of studies published in 2021 that found the skull to be at least 146,000 years old. The researchers argued that the fossil merited a new species name given the unique nature of the skull, naming it Homo longi — which is derived from Heilongjiang, or Black Dragon River, the province where the cranium was found. Some experts at the time hypothesized that the skull might be Denisovan, while others have lumped the cranium in with a cache of difficult-to-classify fossils found in China, resulting in intense debate and making molecular data from the fossil particularly valuable. Given the skull's age and backstory, Fu said she knew it would be challenging to extract ancient DNA from the fossil to better understand where it fit in the human family tree. 'There are only bones from 4 sites over 100,000 (years old) in the world that have ancient DNA,' she noted via email. Fu and her colleagues attempted to retrieve ancient DNA from six samples taken from Dragon Man's surviving tooth and the cranium's petrous bone, a dense piece at the base of the skull that's often a rich source of DNA in fossils, without success. The team also tried to retrieve genetic material from the skull's dental calculus — the gunk left on teeth that can over time form a hard layer and preserve DNA from the mouth. From this process, the researchers managed to recover mitochondrial DNA, which is less detailed than nuclear DNA but revealed a link between the sample and the known Denisovan genome, according to one new paper published in the journal Cell. 'Mitochondrial DNA is only a small portion of the total genome but can tell us a lot. The limitations lie in its relatively small size compared to nuclear DNA and in the fact that it is only inherited from the matrilineal side, not both biological parents,' McCrae said. 'Therefore, without nuclear DNA a case could be made that this individual is a hybrid with a Denisovan mother, but I think that scenario is rather less likely than this fossil belonging to a full Denisovan,' he added. The team additionally recovered protein fragments from the petrous bone samples, the analysis of which also suggested the Dragon Man skull belonged to a Denisovan population, according to a separate paper published Wednesday in the journal Science. Together, 'these papers increase the impact of establishing the Harbin cranium as a Denisovan,' Fu said. The molecular data provided by the two papers is potentially very important, said anthropologist Chris Stringer, research leader in human origins at London's Natural History Museum. 'I have been collaborating with Chinese scientists on new morphological analyses of human fossils, including Harbin,' he said. 'Combined with our studies, this work makes it increasingly likely that Harbin is the most complete fossil of a Denisovan found so far.' However, Xijun Ni, a professor at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing who, along with Stringer, worked on the initial Dragon Man research but not the latest studies, said that he is cautious about the outcome of the two papers because some of the DNA extraction methods used were 'experimental.' Ni also said he finds it strange that DNA was obtained from surface dental calculus but not inside the tooth and petrous bone, given that the calculus appeared to be more exposed to potential contamination. Nonetheless, he added that he thinks it is likely the skull and other fossils identified as Denisovan are from the same human species. The goal in using a new extraction approach was to recover as much genetic material as possible, Fu explained, adding that the dense crystalline structure of dental calculus may help prevent the host DNA from being lost. The protein signatures Fu and her team recovered indicated 'a Denisovan attribution, with other attributions very unlikely,' said Frido Welker, an associate professor of biomolecular paleoanthropology at the University of Copenhagen's Globe Institute in Denmark. Welker has recovered Denisovan proteins from other candidate fossils but was not involved in this research. 'With the Harbin cranium now linked to Denisovans based on molecular evidence, a larger portion of the hominin fossil record can be compared reliably to a known Denisovan specimen based on morphology,' he said. With the Dragon Man skull now linked to Denisovans based on molecular evidence, it will be easier for paleoanthropologists to classify other potential Denisovan remains from China and elsewhere. McRae, Ni and Stringer all said they thought it was likely that Homo longi would become the official species name for Denisovans, although other names have been proposed. 'Renaming the entire suite of Denisovan evidence as Homo longi is a bit of a step, but one that has good standing since the scientific name Homo longi was technically the first to be, now, tied to Denisovan fossils,' McRae said. However, he added that he doubts the informal name of Denisovan is going anywhere anytime soon, suggesting it might become shorthand for the species, as Neanderthal is to Homo neanderthalensis. The findings also make it possible to say a little more about what Denisovans might have looked like, assuming the Dragon Man skull belonged to a typical individual. According to McRae, the ancient human would have had very strong brow ridges, brains 'on par in size to Neanderthals and modern humans' but larger teeth than both cousins. Overall, Denisovans would have had a blocky and robust-looking appearance. 'As with the famous image of a Neanderthal dressed in modern attire, they would most likely still be recognizable as 'human,'' McRae said. 'They are still our more mysterious cousin, just slightly less so than before,' he added. 'There is still a lot of work to be done to figure out exactly who the Denisovans were and how they are related to us and other hominins.'
CNN
2 days ago
- Science
- CNN
A skull found in a well defied classification. Now it could help unravel an evolutionary mystery
An enigmatic skull recovered from the bottom of a well in northeastern China in 2018 sparked intrigue when it didn't match any previously known species of prehistoric human. Now, scientists say they have found evidence of where the fossil fits, and it could be a key piece in another cryptic evolutionary puzzle. After several failed attempts, the researchers managed to extract genetic material from the fossilized cranium — nicknamed Dragon Man — linking it to an enigmatic group of early humans known as Denisovans. A dozen or so Denisovan fossilized bone fragments had previously been found and identified using ancient DNA. But the specimens' small size offered little idea of what this shadowy population of ancient hominins looked like, and the group has never been assigned an official scientific name. Scientists typically consider skulls, with telltale bumps and ridges, the best type of fossilized remains to understand the form or appearance of an extinct hominin species. The new findings, if confirmed, could effectively put a face to the Denisovan name. 'I really feel that we have cleared up some of the mystery surrounding this population,' said Qiaomei Fu, a professor at the Institute of Paleontology and Paleoanthropology, part of the Chinese Academy of Sciences in Beijing, and lead author of the new research. 'After 15 years, we know the first Denisovan skull.' Denisovans were first discovered in 2010 by a team that included Fu — who was then a young researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany — from ancient DNA contained in a pinkie fossil found in Denisova Cave in the Altai Mountains of Russia. Additional remains unearthed in the cave, from which the group gets its name, and elsewhere in Asia continue to add to the still-incomplete picture. The new research, described in two scientific papers published Wednesday, is 'definitely going to be among, if not the, biggest paleoanthropology papers of the year,' and will spur debate in the field 'for quite some time,' said Ryan McRae, a paleoanthropologist at the Smithsonian National Museum of Natural History in Washington, DC, who was not involved in the studies. The findings could help fill in gaps about a time when Homo sapiens weren't the only humans roaming the planet — and teach scientists more about modern humans. Our species once coexisted for tens of thousands of years and interbred with both Denisovans and Neanderthals before the two went extinct. Most humans today carry a genetic legacy of those ancient encounters. Neanderthal fossils have been the subject of study for than a century, but scant details are known about our mysterious Denisovan cousins, and a skull fossil can reveal a great deal. A laborer in the city of Harbin in northeastern China discovered the Dragon Man skull in 1933. The man, who was constructing a bridge over the Songhua River when that part of the country was under Japanese occupation, took home the specimen and stored it at the bottom of a well for safekeeping. The man never retrieved his treasure, and the cranium, with one tooth still attached in the upper jaw, remained unknown to science for decades until his relatives learned about it before his death. His family donated the fossil to Hebei GEO University, and researchers first described it in a set of studies published in 2021 that found the skull to be at least 146,000 years old. The researchers argued that the fossil merited a new species name given the unique nature of the skull, naming it Homo longi — which is derived from Heilongjiang, or Black Dragon River, the province where the cranium was found. Some experts at the time hypothesized that the skull might be Denisovan, while others have lumped the cranium in with a cache of difficult-to-classify fossils found in China, resulting in intense debate and making molecular data from the fossil particularly valuable. Given the skull's age and backstory, Fu said she knew it would be challenging to extract ancient DNA from the fossil to better understand where it fit in the human family tree. 'There are only bones from 4 sites over 100,000 (years old) in the world that have ancient DNA,' she noted via email. Fu and her colleagues attempted to retrieve ancient DNA from six samples taken from Dragon Man's surviving tooth and the cranium's petrous bone, a dense piece at the base of the skull that's often a rich source of DNA in fossils, without success. The team also tried to retrieve genetic material from the skull's dental calculus — the gunk left on teeth that can over time form a hard layer and preserve DNA from the mouth. From this process, the researchers managed to recover mitochondrial DNA, which is less detailed than nuclear DNA but revealed a link between the sample and the known Denisovan genome, according to one new paper published in the journal Cell. 'Mitochondrial DNA is only a small portion of the total genome but can tell us a lot. The limitations lie in its relatively small size compared to nuclear DNA and in the fact that it is only inherited from the matrilineal side, not both biological parents,' McCrae said. 'Therefore, without nuclear DNA a case could be made that this individual is a hybrid with a Denisovan mother, but I think that scenario is rather less likely than this fossil belonging to a full Denisovan,' he added. The team additionally recovered protein fragments from the petrous bone samples, the analysis of which also suggested the Dragon Man skull belonged to a Denisovan population, according to a separate paper published Wednesday in the journal Science. Together, 'these papers increase the impact of establishing the Harbin cranium as a Denisovan,' Fu said. The molecular data provided by the two papers is potentially very important, said anthropologist Chris Stringer, research leader in human origins at London's Natural History Museum. 'I have been collaborating with Chinese scientists on new morphological analyses of human fossils, including Harbin,' he said. 'Combined with our studies, this work makes it increasingly likely that Harbin is the most complete fossil of a Denisovan found so far.' However, Xijun Ni, a professor at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing who, along with Stringer, worked on the initial Dragon Man research but not the latest studies, said that he is cautious about the outcome of the two papers because some of the DNA extraction methods used were 'experimental.' Ni also said he finds it strange that DNA was obtained from surface dental calculus but not inside the tooth and petrous bone, given that the calculus appeared to be more exposed to potential contamination. Nonetheless, he added that he thinks it is likely the skull and other fossils identified as Denisovan are from the same human species. The goal in using a new extraction approach was to recover as much genetic material as possible, Fu explained, adding that the dense crystalline structure of dental calculus may help prevent the host DNA from being lost. The protein signatures Fu and her team recovered indicated 'a Denisovan attribution, with other attributions very unlikely,' said Frido Welker, an associate professor of biomolecular paleoanthropology at the University of Copenhagen's Globe Institute in Denmark. Welker has recovered Denisovan proteins from other candidate fossils but was not involved in this research. 'With the Harbin cranium now linked to Denisovans based on molecular evidence, a larger portion of the hominin fossil record can be compared reliably to a known Denisovan specimen based on morphology,' he said. With the Dragon Man skull now linked to Denisovans based on molecular evidence, it will be easier for paleoanthropologists to classify other potential Denisovan remains from China and elsewhere. McRae, Ni and Stringer all said they thought it was likely that Homo longi would become the official species name for Denisovans, although other names have been proposed. 'Renaming the entire suite of Denisovan evidence as Homo longi is a bit of a step, but one that has good standing since the scientific name Homo longi was technically the first to be, now, tied to Denisovan fossils,' McRae said. However, he added that he doubts the informal name of Denisovan is going anywhere anytime soon, suggesting it might become shorthand for the species, as Neanderthal is to Homo neanderthalensis. The findings also make it possible to say a little more about what Denisovans might have looked like, assuming the Dragon Man skull belonged to a typical individual. According to McRae, the ancient human would have had very strong brow ridges, brains 'on par in size to Neanderthals and modern humans' but larger teeth than both cousins. Overall, Denisovans would have had a blocky and robust-looking appearance. 'As with the famous image of a Neanderthal dressed in modern attire, they would most likely still be recognizable as 'human,'' McRae said. 'They are still our more mysterious cousin, just slightly less so than before,' he added. 'There is still a lot of work to be done to figure out exactly who the Denisovans were and how they are related to us and other hominins.'
