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Scientists Discover New Early Human Species

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Dekator
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« on: September 11, 2015, 02:14:39 am »


Scientists Discover New Early Human Species

Thu, Sep 10, 2015




Massive South African fossil trove shakes up the human family tree.
Scientists Discover New Early Human Species

They were having the time of their lives. 

In late 2013 and early 2014 they uncovered more than 1,550 bones representing at least 15 ancient individuals from a small, dark, nearly inaccessible chamber in the Dinaledi (or "Rising Star") cave system in South Africa. At any level, this was an extremely rare event. Then, after meticulous analysis of the bones, the scientists knew they had come across something remarkable. So remarkable, in fact, they decided to designate the bones as belonging to an entirely new species of hominin. They called it Homo naledi.

The Dinaledi finds went on record as the largest single assemblage of hominin fossils in any one location in Africa. What's more, “the combination of anatomical features in H. naledi distinguishes it from any previously known species,” said Lee Berger of the University of the Witwatersrand. Berger led the two expeditions* that discovered and recovered the fossils. “With almost every bone in the body represented multiple times, Homo naledi is already practically the best-known fossil member of our lineage.”

So what were these scientists looking at?

“Overall, Homo naledi looks like one of the most primitive members of our genus, but it also has some surprisingly human-like features, enough to warrant placing it in the genus Homo,” said John Hawks of the University of Wisconsin-Madison, U.S., an expedition participant and a senior author of the research paper describing the new species. “H. naledi had a tiny brain, about the size of an average orange (about 500 cubic centimeters), perched atop a very slender body.” The research shows that on average H. naledi stood approximately 1.5 meters (about 5 feet) tall and weighed about 45 kilograms (almost 100 pounds).

A gracile creature with a brain not much larger than a chimpanzee.

But this was no chimpanzee. This was something else. Something more human.

According to the examining scientists, this creature had teeth and skull features similar to those of the earliest-known members of our genus, such as Homo habilis. Certain key features of the hands suggested “tool-using capabilities”, according to Dr. Tracy Kivell of the University of Kent, U.K., who was part of the team that studied H. naledi’s anatomy. And the feet were even more telling. Other than a few notable characteristics, they were “virtually indistinguishable from those of modern humans,” said Dr William Harcourt-Smith of Lehman College, City University of New York, and the American Museum of Natural History, who led the study of H. naledi’s feet. Its feet, combined with its long legs, he suggested, indicated that the species was well-suited for upright, long-distance walking—just like us. These were all trademark traits attributable to humans.

But there were clearly more “primitive”, ape-like traits, as well. The much smaller brain, for one. The shoulders were much more similar to those of apes, and like apes, the fingers of the hand had “extremely curved fingers, more curved than almost any other species of early hominin, which clearly demonstrates climbing capabilities,” said Kivell—features that facilitated a tree-climbing life. Moreover, the pelvis resembled that of an Australopithecine, a more ape-like protohuman relative, fossils of which have now long been a part of the broad range of hominin finds to date.
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Dekator
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« Reply #1 on: September 11, 2015, 02:15:42 am »



The braincase of a composite male skull of H. naledi measures just 560 cubic centimeters in volume — less than half that of the modern human skull pictured behind it. The fossils were recovered from the Rising Star cave in South Africa by a team led by National Geographic Explorer-in-Residence Lee Berger of the University of the Witwatersrand. Art: Stefan Fichtel. Sources: Lee Berger and Peter Schmid, Wits; John Hawks, University of Wisconsin-Madison/National Geographic
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« Reply #2 on: September 11, 2015, 02:16:12 am »



A composite skeleton of H. naledi is surrounded by some of the hundreds of other fossil elements recovered from the Dinaledi Chamber in the Rising Star cave in South Africa. The expedition team was led by National Geographic Explorer-in-Residence Lee Berger of the University of the Witwatersrand. Photo by Robert Clark/National Geographic; Source: Lee Berger, Wits, photographed at Evolutionary Studies Institute
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« Reply #3 on: September 11, 2015, 02:17:03 am »

An ancient depository for the dead?

Perhaps most significantly, study of the context of the finds has led the researchers to conclude that H. naledi may have practiced a form of behavior previously thought to be unique to humans. The fossils, consisting of infants, children, adults and elderly individuals, were found in a deep underground room that has “always been isolated from other chambers and never been open directly to the surface,” said Dr Paul Dirks of James Cook University in Queensland, Australia, lead author of the eLife paper on the context of the find. “What’s important for people to understand is that the remains were found practically alone in this remote chamber in the absence of any other major fossil animals.”

So remote was the space that out of more than 1,550 fossil elements recovered, only about a dozen are not hominin, and these few pieces are isolated mouse and bird remains, meaning that the chamber attracted few accidental visitors. The bones show no marks of scavengers or carnivores or any other signs that non-hominin agents or natural processes, such as moving water, carried these individuals into the chamber. Moreover, there was no evidence that the chamber was ever used as an actual living space by humans. “We explored every alternative scenario, including mass death, an unknown carnivore, water transport from another location, or accidental death in a death trap, among others,” said Berger. “In examining every other option, we were left with intentional body disposal by Homo naledi as the most plausible scenario.” This suggests the possibility of a form of ‘ritualized’ behavior previously thought to be unique to humans (“ritualized” meaning repeated behavior.)

The million dollar question: How old?

Now that scientists have discovered this new hominin species, what about the age?

Unlike other fossil deposits in caves, these fossils were found with very few or no fossils of other animals that could be directly associated with the finds, making it impossible to determine a faunal age. The few flowstones in the cave that can be directly linked to the fossils are contaminated with clays, making them very difficult to date. Moreover, the fossils are contained in soft sediments that have been partly re-worked and re-deposited by acts of nature over time, making it extremely difficult to establish their primary stratigraphic position.

“We have tried three approaches that have failed to give dates for the actual fossils, and are currently working on further attempts,” report Berger and the scientific team. “Because of the uniqueness of the fossils and the situation in which they are found, we only want to publish age limits for them when we are absolutely sure that they are right.”

Nevertheless, given the geographic context with proximity to other already dated caves in the area, such as Sterkfontein, Swartkrans, and Malapa, the scientists suspect that the Dinaledi cave system may fall within the 2-to-3-million-year-old time range, possibly placing H. nadeli near or at the root of the genus Homo, considering the morphology. But at this point, it would be an educated guess.

The Expeditions

The story of this discovery really began with two cavers, Rick Hunter and Steven Tucker, who found the entrance to the Dinaledi Chamber and discovered the fossils. They showed pictures of the fossils to Pedro Boshoff, another caver and geologist. Recognizing the fossils as potentially significant, Boshoff alerted Professor Lee Berger, who then spearheaded the assembly of an expeditionary group (called the "Rising Star Expedition") of scientists.

On November 10, 2013 the first of these explorers entered the chamber, initiating the first of two expeditionary efforts, the first lasting about 21 days and the second, in early 2014, lasting about one week. The task was not an easy one. Carefully excavating the fossil elements with tools as delicate as toothpicks and brushes, they gently removed the fossils, piece by piece, and transported them up through the narrow 7.5-inch chute, including a second narrow area called the ‘superman’s crawl’ only 10 inches wide, to the surface. More than 60 cavers and scientists worked together in what Marina Elliott, one of the excavating scientists, described as “some of the most difficult and dangerous conditions ever encountered in the search for human origins”. Elliott was one of six women selected as “underground astronauts” from a global pool of candidates after Berger issued a call on social media for experienced scientist/cavers who could fit through the 18-centimeter cave opening. Social media continued to play a role in the project, as the team shared expedition progress with a large public audience, schoolchildren and scientists. “This was a first in the history of the field,” said Hawks, who worked with Berger to design the media outreach.

The fossils were subsequently analyzed in a unique workshop in May 2014 funded by the South African DST/NRF, Wits University and National Geographic. More than 50 experienced scientists and early-career researchers came together to study and analyze the treasure trove of fossils and to compose scientific papers.

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« Reply #4 on: September 11, 2015, 02:18:03 am »

Going forward

Berger and his team conclude, as they did at the discovery of Australopithecus sediba in 2008, that there are clearly other key transitional forms of hominins that may yet be discovered and added to the fossil record.  H. naledi is joining an expanding mosaic of hominin species on an ancient African landscape.

“If we learned about a completely new form of hominin only because a couple of cavers were skinny enough to fit through a crack in a well-explored South African cave, we really don’t have a clue what else might be out there,” National Geographic Executive Editor for Science Jamie Shreeve writes about the discovery in National Geographic magazine.

And much remains to be discovered in the Rising Star cave. “This chamber has not given up all of its secrets,” Berger said. “There are potentially hundreds if not thousands of remains of H. naledi still down there.”

Read the detailed study reports in eLife.

*Lee Berger of the Evolutionary Studies Institute, University of the Witwatersrand (Wits University), led the international team of scientists under the joint sponsorship of Wits, the National Geographic Society, and the South African Department of Science and Technology/National Research Foundation,
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« Reply #5 on: September 11, 2015, 02:18:21 am »

http://popular-archaeology.com/issue/fall-2015/article/scientists-discover-new-early-human-species
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« Reply #6 on: September 12, 2015, 05:16:55 pm »

DNA from Neandertal relative may shake up human family tree

Ann is a contributing correspondent for Science
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By Ann Gibbons
11 September 2015 10:15 am


LONDON—In a remarkable technical feat, researchers have sequenced DNA from fossils in Spain that are about 300,000 to 400,000 years old and have found an ancestor—or close relative—of Neandertals. The nuclear DNA, which is the oldest ever sequenced from a member of the human family, may push back the date for the origins of the distinct ancestors of Neandertals and modern humans, according to a presentation here yesterday at the fifth annual meeting of the European Society for the study of human evolution.

Ever since researchers first discovered thousands of bones and teeth from 28 individuals in the mid-1990s from Sima de los Huesos (“pit of bones”), a cave in the Atapuerca Mountains of Spain, they had noted that the fossils looked a lot like primitive Neandertals. The Sima people, who lived before Neandertals, were thought to have emerged in Europe. Yet their teeth, jaws, and large nasal cavities were among the traits that closely resembled those of Neandertals, according to a team led by paleontologist Juan-Luis Arsuaga of the Complutense University of Madrid. As a result, his team classified the fossils as members of Homo heidelbergensis, a species that lived about 600,000 to 250,000 years ago in Europe, Africa, and Asia. Many researchers have thought H. heidelbergensis gave rise to Neandertals and perhaps also to our species, H. sapiens, in the past 400,000 years or so.

But in 2013, the Sima fossils’ identity suddenly became complicated when a study of the maternally inherited mitochondrial DNA (mtDNA) from one of the bones revealed that it did not resemble that of a Neandertal. Instead, it more closely matched the mtDNA of a Denisovan, an elusive type of extinct human discovered when its DNA was sequenced from a finger bone from Denisova Cave in Siberia. That finding was puzzling, prompting researchers to speculate that perhaps the Sima fossils had interbred with very early Denisovans or that the “Denisovan” mtDNA was the signature of an even more ancient hominin lineage, such as H. erectus. At the time, researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who had obtained the mtDNA announced that they would try to sequence the nuclear DNA of the fossils to solve the mystery.

After 2 years of intense effort, paleogeneticist Matthias Meyer of the Max Planck Institute for Evolutionary Anthropology has finally sequenced enough nuclear DNA from fossils of a tooth and a leg bone from the pit to solve the mystery. The task was especially challenging because the ancient DNA was degraded to short fragments, made up of as few as 25 to 40 single nucleotides. (Nucleotides—also known as base pairs—are the building blocks of DNA.) Although he and his colleagues did not sequence the entire genomes of the fossils, Meyer reported at the meeting that they did get 1 million to 2 million base pairs of ancient nuclear DNA.

They scanned this DNA for unique markers found only in Neandertals or Denisovans or modern humans, and found that the two Sima fossils shared far more alleles—different nucleotides at the same address in the genome—with Neandertals than Denisovans or modern humans. “Indeed, the Sima de los Huesos specimens are early Neandertals or related to early Neandertals,” suggesting that the split of Denisovans and Neandertals should be moved back in time, Meyer reported at the meeting.

Researchers at the meeting were impressed by this new breakthrough in ancient DNA research. “This has been the next frontier with ancient DNA,” says evolutionary biologist Greger Larson of the University of Oxford in the United Kingdom.

The close affinity with Neandertals, but not with Denisovans or modern humans, suggests that the lineage leading to Neandertals was separate from other archaic humans earlier than most researchers have thought. That means that the ancestors of modern humans also had to split earlier than expected from the population that gave rise to Neandertals and Denisovans, who were more closely related to each other than they were to modern humans. (Although all three groups interbred at low levels after their evolutionary paths diverged—and such interbreeding may have been the source of the Denisovan mtDNA in the first Sima fossil whose DNA was sequenced.) Indeed, Meyer suggested in his talk that the ancestors of H. sapiens may have diverged from the branch leading to Neandertals and Denisovans as early as 550,000 to 765,000 years ago, although those results depend on different mutation rates in humans and are still unpublished.

That would mean that the ancestors of humans were already wandering down a solitary path apart from the other kinds of archaic humans on the planet 100,000 to 400,000 years earlier than expected. “It resolves one controversy—that they’re in the Neandertal clade,” says paleoanthropologist Chris Stringer of the Natural History Museum in London. “But it’s not all good news: From my point of view, it pushes back the origin of H. sapiens from the Neandertals and Denisovans.” The possibility that humans were a distinct group so early shakes up the human family tree, promising to lead to new debate about when and where the branches belong.

Posted in Archaeology, Evolution
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« Reply #7 on: September 12, 2015, 05:17:34 pm »



FOSSIL SKULLS AND CHIMPANZEE/J.-J. HUBLIN; BONOBO/ROYAL MUSEUM FOR CENTRAL AFRICA, TERVUREN, BELGIUM
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« Reply #8 on: September 12, 2015, 05:17:57 pm »

http://news.sciencemag.org/archaeology/2015/09/dna-neandertal-relative-may-shake-human-family-tree
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« Reply #9 on: September 14, 2015, 10:35:58 am »

Lot's of hybrid match ups when the Nefilim were combining ape and Nefilim DNA to create workers to mine their gold and farm their lands.
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