Denisovans

2022 - 5 - 18

Denisovan tooth found in Laos (Cosmos)

Denisovans, the mysterious archaic humans first identified in a cave in Siberia, also lived down under. We know that because indigenous Papuans and Australians ...

But to close the case on whether or not she really was a tropical Denisovan, more of her kind will need to be found. There’s never been a more important time to explain the facts, cherish evidence-based knowledge and to showcase the latest scientific, technological and engineering breakthroughs. Could it be, at last, a remnant of the long-sought southern Denisovan? Instead of scanning the outer cusps, which may be worn or broken, he uses a miniature CT scanner to look at the pristine pattern just underneath the enamel layer, the so-called enamel-dentine junction, or EDJ. The first clue came from a finger bone fragment, one of the middle bones of a pinky, found in a jumble of bone fragments in Denisova Cave near the border of Siberia and China. The pinky bone looked like it came from a human. Jian-Xin Zhao from University of Queensland dated the flowstones above the gravel using a uranium series. But they were for Fabrice Demeter, a paleoanthropologist at the University of Copenhagen and lead author of the new study. Were the baubles in this cement cake all baked in at the same time, or had some fallen in later, perhaps when a tree root pierced the layer? Unlike the cave of monkeys it was not habitable. The forensic analyses all agreed: the layer was intact and had been deposited between 164,000 and 131,000 years ago. Now an international team may have found them in the form of a 160,000–130,000-year-old tooth unearthed from Cobra cave in the remote Annamite mountains of northern Laos. So distinctive was the DNA, that geneticists could pick out traces of it in modern human populations.

Tooth from mysterious human relative adds new wrinkles to their story (National Geographic)

Discovered thousands of miles south of the only other known Denisovan fossils, the molar provides fresh evidence of the enigmatic humans' spread across ...

According to Zanolli, the team is analyzing the oxygen and carbon chemistry of the tooth’s enamel. While the Laotian molar is somewhat similar to those of Neanderthals, that species has never been found as far east as Laos, and genetic data show that Denisovans probably lived in Southeast Asia. Yet researchers didn’t find the proteins needed to place the tooth within a specific branch of the hominin family tree. “People who are working on this field in 30, 40, 50 years with totally new technologies are going to appreciate that," says National Geographic Explorer Kendra Sirak, a Harvard Medical School research associate and ancient DNA expert who wasn’t involved with the new study. The Laotian tooth’s lack of roots or surface wear suggests that it belonged to a child who died before their adult teeth had fully formed, likely between 3.5 and 8.5 years of age. After x-ray scanning the fossil to study its shape, the researchers sampled the tooth’s enamel in search of preserved proteins. “It’s really thanks to him that our team has been able to work in Laos,” says Fabrice Demeter, the study’s co-lead author and a paleoanthropologist at the Lundbeck Foundation GeoGenetics Centre in Copenhagen, Denmark. Demeter and Shackelford have each spent more than a decade working in Laos, recently teaming up with cavers to navigate the steep escarpments. In 2018 they caught wind of Cobra Cave, whose entrance sits atop a rock face more than 110 feet above the surrounding plain. “We’re incredibly flexible—that’s sort of the hallmark of modern humans.” Shortly before her first trip into the cave, Shackelford’s colleague had found a particularly exciting fossil within the cave’s constellations of remains: a wrinkly partial molar more than 130,000 years old. After scrambling up a steep rocky pitch in the Annamite Mountains of Laos, Laura Shackelford was initially underwhelmed.

New Fossil Discovery Suggests Denisovans Lived in Laos 164000 ... (Sci-News.com)

A portrait of a juvenile female Denisovan based on a skeletal profile reconstructed from ancient DNA methylation maps. Image credit: Maayan Harel. The Middle ...

“The tooth from Tam Ngu Hao 2 Cave in Laos provides direct evidence of a most likely Denisovan female individual with associated fauna in mainland Southeast Asia by 164,000-131,000 years ago,” the authors said. “This fossil represents the first discovery of Denisovans in Southeast Asia and shows that Denisovans were in the south at least as far as Laos. This is in agreement with the genetic evidence found in modern day Southeast Asian populations.” Paleoanthropologists have found a permanent lower molar of a young, likely female, hominin individual at the Tam Ngu Hao 2 limestone cave in the Annamite Mountains, Laos. The close morphological affinities with the Xiahe specimen from China indicate that the specimen belongs to the same taxon and most likely represents a Denisovan.

Ancient human tooth discovered in Laos cave may be first ... (ABC News)

What links a tooth found in a cave in the limestone landscapes of Laos to a finger bone and some fossil teeth found in a cave in the remote Altai Mountains ...

The area is a warren of limestone caves, some of which are famous for ancient human fossilised remains. But Tam Ngu Hao 2 was part of a larger network of chambers and tunnels. It was only years later that more of its skeleton came to light. Directly dating the tooth could be possible, but that technique would involve cutting into it, so the team decided to leave it whole and date everything around the precious fossil instead. Archaeologists were clued in on the age of the tooth's owner by its pristineness. The molar did not contain that protein type. But overall, the tooth looked remarkably similar to its counterpart attached to what many believe is a Denisovan jawbone found in a cave in Tibet. The team compared lumps and bumps on the tooth's surface and under the enamel with other teeth of a range of different humans — including Neanderthals, Homo erectus, Denisovans and Homo sapiens — to rule them out (or in). In the absence of usable DNA — the heat and humidity of the tropics degrades genetic material quickly — they analysed more robust proteins in the tooth enamel to ascertain if it belonged to a boy or girl. So far, there's a pinky finger bone and a few teeth from Denisova Cave in Russia, plus a jaw bone and a few teeth from Baishiya Cave on the Tibetan Plateau. - A molar found in a Laos cave is purported to be the first Denisovan fossil evidence in South-East Asia A single ancient tooth found in a Laos cave may be the first physical evidence of an extinct, enigmatic group of humans called Denisovans in South-East Asia.

Ancient tooth suggests Denisovans ventured far beyond Siberia (Nature.com)

Molar found in Laos could be the first fossil evidence that the hominin species was far-ranging and able to adapt to different climates.

But Viola says that the molar is in the “right place and right time” to belong to a Denisovan. If this is confirmed, it would reveal that the species was able to adapt to different environmental conditions. The tooth’s roots are not fully developed, so it probably belonged to a child, the researchers say. “So it seems like a good assumption that this is likely a Denisovan.” Dating of the cave’s rock and animal teeth revealed that the tooth pre-dated the arrival of modern humans in the area. But in 2018, Shackelford and her colleagues were looking for potential dig sites in northern Laos when they came across a cave “just filled with teeth”. These belonged to a mixture of species, including giant tapirs, deer, pigs and ancient relatives of modern elephants. If confirmed, it would be the first fossil evidence that Denisovans — an extinct hominin species that co-existed with Neanderthals and modern humans — lived in southeast Asia.

Ancient Tooth Once Belonged to The Mysterious Denisovans ... (ScienceAlert)

Deep in the forests of Laos, in a cave in the Annamite Mountains, lay a single child's tooth. That tooth – an unassuming molar - could be from a mysterious ...

Using sediment from around the tooth, they dated the tooth to between 164 to 131 thousand years old. That tooth – an unassuming molar - could be from a mysterious species of human we know little about, and of which few remains are known to exist. However, finding specimens has been incredibly slim pickings. Because the molar only recently completed development (at the time of the individual's death), and showed no signs of being worn, the team believes that the tooth is from a child between 3.5 to 8.5 years old when they died. "The tooth from Tam Ngu Hao 2 Cave in Laos thus provides direct evidence of a most likely Denisovan female individual with associated fauna in mainland Southeast Asia by 164-131 thousand years ago," the team writes in their new paper. "Analyses of the internal structure of the molar in tandem with palaeoproteomic analyses of the enamel indicate that the tooth derives from a young, likely female, Homo individual," researchers write in a new study.

Ancient tooth of mysterious Denisovan girl possibly found (Livescience.com)

Researchers in Laos have uncovered an ancient molar that may have belonged to a Denisovan girl who lived up to 164000 years ago.

Given that caveat, "I think it is a good study and the conclusions are strong," Bailey said. Although the scientists could not exclude it as belonging to a Neanderthal, they suggested its close physical similarity to a Denisovan specimen from China indicated that the molar was likely Denisovan. (The researchers did not analyze the fossil for ancient DNA because this genetic material rarely preserves well in the type of sediment found in the cave and in tropical conditions present in Laos.) The tooth was a molar that had not yet erupted from the left side of the lower jaw. Scientists discovered the tooth in 2018 in a site known as Cobra Cave in the Annamite Mountains of Laos, which has an entrance located about 110 feet (34 meters) above the ground. Scientists who discovered a skull in China dubbed " Dragon Man" claimed it belonged to a newfound species, Homo longi, but many other researchers suspect it may be a Denisovan skull.