Daily Archives: May 9, 2017

Homo naledi, a strange new species of human cousin found in South Africatwo years ago, was unlike anything scientists had ever seen. Discovered deep in the heart of a treacherous cave system as if they'd been placed there deliberately were 15 ancient skeletons that showed a confusing patchwork of features. Some aspects seemed modern, almost human. But their brains were as small as a gorilla's, suggesting Homo nalediwas incredibly primitive. The species was an enigma.

Now, the scientists who uncovered Homo naledihave announced two new findings: They have determined a shockingly young age for the original remains, and they found a second cavern full of skeletons. The bones are as recent as 236,000 years, meaning Homo nalediroamed Africa at about the time our own species was evolving. And the discovery of a second cave adds to the evidence that primitive Naledi may have performed a surprisingly modern behavior: burying the dead.

This is a humbling discovery for science, said Lee Berger, a paleoanthropologist at the University of the Witwatersrand in Johannesburg. It's reminding us that the fossil record can hide things we can never assume that what we have tells the whole story.

Berger and his colleagues report Naledi's age and the new chamber in two papers published Tuesday in the open-access journal eLife. In a third paper, they argue that Naledi must be a long-lasting lineage that arose 2 million years ago during the early days of the genus Homo and somehow survived long enough to coexist with modern humans, who emerged about 200,000 years ago. The species' complicated anatomy and unexpected resilience raise a number of intriguing questions, they say: Was Naledi a result of, and perhaps a contributor to, hybridization within the Homofamily tree?Could Naledi be responsible for some of the stone tools found in South Africa during the period it was alive? Should paleoanthropologists shift their focus from East Africa to the continent's less-studied southern regions?

Several scientists not involved the Naledi research urged caution about some of Berger's bolder claims, including the suggestion that Naledi was burying its dead and crafting the sophisticated stone tools that characterize southern Africa's Middle Stone Age.

But they agreed with Berger on this point: Naledi reminds us that human history is even richer than we realized.

The past was a lot more complicated than we gave it credit for and our ancestorswere a lot more resilientand lot more varied than we give them credit for, said Susan Anton, a paleoanthropologist at New York University who was not involved in theresearch. We'renot the pinnacle of everything that happened in the past. We just happen to be the thing that survived.

Rick Potts, director of the Human Origins Program at the Smithsonian Institution's National Museum of Natural History, said finds like this should prompt people todiscard the familiar image of a stooped chimp evolving into a modern human walking upright and carrying a briefcase.

We'vehad for so long this view that human evolution was a matter of inevitability represented by that march, that progress, he said. But now that narrative of human evolution has become one ofadaptability. There was a lot of evolution and extinction of populations and lineages that made it through some pretty tough times, and we're the beneficiary of that.

The original Homo naledi skeletons were discovered in 2013 in the Rising Star cave system, one of the twisted and branching limestone caverns that make up a World Heritage Site known as the Cradle of Humankind. This same 180-square-mile region in South Africa has yielded a number of 2-million-year-old Australopithecus fossils, but Homo naledi was the first species to fit in the genus Homo.

The Dinaledi (star in the Sesotho language) chamber, which contained the Naledi skeletons, was so narrow and difficult to access that Berger had to seek out an all-women team of petite, extremely agile spelunkersto excavate it. What they found astonished the paleoanthropology community not only had a new species been discovered but, with 15 skeletons, it was suddenly the best-documented species in the history of hominins.

And theRising Star system wasn't done giving up its secrets.SpelunkersRick Hunter and Steven Tucker, who discovered the bones in the Dinaledi chamber, had alsonoticed a large leg bone in a different part of the cave. They didn't think much of it at the time, but after the importance of the Dinaledi fossils became clear, they realized the bone they had passed before was probably from a hominin. As soon as the Dinaledi excavation was complete, the team went back to this second chamber, dubbed Lesedi (light").

Lesedi was shallower and easier to access than the Dinaledi chamber, but only marginally so. It fit just oneexcavator at a time, working on his or her hands and knees to brush reddish brown clay from fragile bones. Berger himself only ventured into the chamber once he got stuck coming back out of the narrow entrance and decided not to pushhis luck again.

Yet, somehow, more than 130 hominin bones wound up in this dark and humid cavern hundreds of thousands of years ago. The excavators uncovered remains from at least three Homo naledi individuals. One of them, an adult male they call Neo (gift in Sesotho), is arguably the most complete fossil hominin ever found.

Berger and his colleagues don't yet have an age for the Lesedi individuals, and without DNA evidence from both caverns, it will be impossible to tell whether they are related to those from Dinaledi. But he and his colleagues argue that the presence of a second cavern full of bones bolsters thetheory that Homo naledi was deliberately leavingits dead in these chambers.

One, perhaps, was a singular event, Berger said. Two is not a coincidence.

Not everyone is convinced. Ritual disposal of the dead is an advanced behavior, suggesting that a species was capable of symbolic thought and saw itself as separate from the natural world.Only humans and Neanderthals have been conclusively found to bury their dead, and several scientists said we cannot yet rule out the possibility that the bones were deposited in the cave naturally. The Lesedi chamber also yielded some small animal fossils. (The absence of nonhuman remains in Dinaledi was considered a strong piece of evidence that the hominins were placed in the cavern intentionally, rather than falling or wandering into the cave and then dying there.)

Scientists say new bones of homo naledi reveal they existed at about the same time homo sapiens evolved. (Reuters)

Alison Brooks, a paleoanthropologist at George Washington University and the Smithsonian Institution who was not involved in the research, suggested that the immediate ancestors ofHomo sapiensmight be the ones who put the bodies there. She said it is possible theydropped the bodies into the caverns throughan opening that has long since closed. She noted that no artifacts were found with the caverns that might indicate how to interpret the remains. She also questioned whether the cave was really asdifficult to accessin the past as it is today.

But if Homo naledi was placing the bones in the cave for ritual reasons, that wouldmean the specieswas capable of something profound.

There's a potential that we are looking at some kind of rudimentary cultural practice associated with this widely shared emotion of grief, said John Hawks, a paleoanthropologist at the University of Wisconsin at Madison who helped lead the Rising Star expedition. It'stellingus that this is something that's very deep in our history as humans. When you're looking at a group that takes one of their members and takes the body and put it somewherehidden, thats like saying, 'Were different.The leopards are not going to eat you. Youre one of us.'

Yet even as the scientists puzzled over the implications of the second cave, they still had to figure out the age of the fossils in the first one. In a 2015 interview with National Geographic (which helped fund the Rising Star excavations), Berger speculated that Naledi had emerged about 2 million years ago, based on its constellation of traits, and was positioned near the root of the Homofamily tree.

Homo naledi's small brain case and curved fingers suggested the species was primitive, more closely related to our Australopithecus ancestors than to us. But its long legs, small teeth and dexterous wrists appeared modern. The bones were too old to be dated using the traditional radiocarbon technique, and too poorly preserved for researchers to extract any ancient DNA.

Meanwhile the stratigraphy, or ordering of the rock layers, of the Dinaledi chamber was difficult to decipher. Water had periodically washed through the cavern during its several-hundred-thousand-year history, causing sediments to accumulate weirdly. Water also affects radiation levels in the chamber, which can throw off calculations of age based on rates of radioactive decay.

All this gets quite, quite complicated, and this is one of the reasons why it took so long to do, said Paul Dirks, a geologist at James Cook University in Australia who led the dating effort. We did not want to put a garbage age out there.

In the end, the research team employed six different dating techniques at 10 labs around the world. Each technique was tried independently by at least two labs to ensure that the results were as robust as possible. Based on analysis of the Naledi teeth and several measures of radioactivity in the cave, the team concluded that the fossils date back to between 236,000 and 335,000 years ago just beforethe arrival of modern humans.

Our ancestorsdid not live in a single species world the way we do, Brooks said. The real take-home message of this paper is that we were not alone until very recently.

Several other hominin species roamed the globe during this period, known as the Middle Stone Age:Homo erectus in Asia; tall, large-brained Homo heidelbergensisin Africa and Europe; eventually Neanderthals and the mysterious Denisovans (who are known only from DNA and a few fossil teeth). But these species were a lot like us: They walked primarily on two feet,used tools and probably mastered fire.Even the smallest-brained species had a brain that was three-quarters the size of ours.

For years, scientists assumed that all members of the Homo genus in Africa were quite advanced by the Middle Stone Age how else would they be able to compete with the formidable new speciesHomo sapiens and its direct ancestors?

Homo naledi complicates that narrative. Its limbs and teeth suggest that it had a human's walking habits and diet, and perhaps roamed the same lands and ate the same foods asour recent ancestors. But its brain was only 30 percent the size of a human's, and no bigger than that of a gorilla today.

How the heck did these guys survive alongside of us, alongsideourancestors? Hawks wondered.

Perhaps, he speculated, brain size is not everything. After all, Naledi was arguablyable to navigate the Rising Star cave system. He and Berger both suggested the species may have been capable of other feats of intelligence, including crafting the stone tools normally attributed to Homo sapiens and our direct ancestors.

Pottsofthe National Museum of Natural History,compared Naledi to Homo floresiensis, the tiny, small-brained hobbit people who lived on the Indonesian island of Flores until about 60,000 years ago. Scientists think that the Flores people descended from taller human species but shrank as a result of island dwarfism, the tendency of species trapped on islands with limited resources to evolve smaller stature, requiring less food. Perhaps Naledi evolved from a similar phenomenon, Potts said.

Africa can be seen as an island of forests in a sea of grass, he said. There are all sorts of refuges that occur and the great biodiversity of Africa emerges through that. Nature constantly experiments in isolated evolution, and this happens to have occurred in our own evolutionary tree, and that's just really neat.

But Berger brushed off the comparison to Homo floresiensis. Southern Africa isn't an island,he said, and Homo naledi did not evolve in isolation.

We have a very healthy population of individuals that survived for millions of years and are clearly well adapted to their environment, Berger said. That has profound implications.You cant just write them off.

Berger and Hawks hedged when asked where Homo naledi might fit on the human family tree.

The late age for the Dinaledi skeletons suggests that the species survived for many years, but more research is needed to pin down whenit first evolved. The species may have emerged near the root of the Homo genus, during an initial phase of diversification that gave rise to Homo habilisand other primitive species. Or itcould have branched off later, and may be even more closely related to Neanderthals and modern humans than Homo erectus is.

But both said it might be more accurate to think of human evolution as a stream rather than a branching tree. Tributaries maysplit off from the main waterway and then loop back; species may diverge, then interbreed. Naledi, with its amalgam of advanced and primitive features, could be a result of hybridization. It may also have contributed to the human gene pool:researchsuggests that many modern humans retain traces of an archaic species in our DNA.

In all likelihood,Hawks said, the full story of human evolutionhas not been uncovered yet. If a species such asHomo naledisurvivedfor millions of years without us realizing it, what else might the fossil record be hiding?

We keep finding stuff that we didnt think existed, Hawks said. This is not the first, and it's not going to be the last.

Read more:

Archaeology shocker: Study claims humans reached the Americas 130,000 years ago

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Scientists sequence the genome of a 45,000-year-old man the earliest human genome ever analyzed

170,000 years before Stonehenge, Neanderthals built their own incredible structure

See the original post:
Humanity's strange new cousin is shockingly young and shaking up our family tree - Washington Post

Warning: This post includes images of human remains that might be disturbing to some readers.

Although they are herbivores, deer have been spotted eating meat and gnawing on bones before. But not this kind of bones.

Peer closely at the photos below, and you might discern that dem bonesare people bones. More precisely, they are rib bones.

Wellget right out of the way that no horrified relatives are just now learning that their missing loved ones fate was to be deer dinner. The body from which these bones came was placed withthe highest scientific goals in mind on the floor of that forest, which is better known as the ForensicAnthropology Research Facility in San Marcos, Texas.

The 26-acre facility is one of several body farms around the nation where researchersplunk donated bodies out in the elementsto study the process of human decay and decomposition.Usually the bodies are placed inside a cage to prevent the interference of scavengers. But sometimestheyreleft unprotectedto see justwho might come along to snack on the carcass. Images from remote cameras have revealed that regular diners include rodents, coyotes, raccoons and foxes.

[Nest cam livestreams bald eagle parents feeding a cat to their eaglets]

This particular body, which researchers deposited in July 2014, was initially stripped by vultures. Then, the following January, a remote camera snapped shots of a new visitor to the scene: a young white-tailed deer. It looked very daintybut for the human rib bone extending from the side of the mouth like a cigar, in the words ofthe researchers, who wrote about these first-ever imagesin the Journal of Forensic Sciences.

Eight days later at the same location, a deer maybe the same one was spotted casually gnawing on another rib bone, looking like one of those rare people who make it through a giant turkey leg at a Renaissance festival.

Other ungulates, or hooved mammals, have also been known to nibble on animal remainsdespite their vegetarian reputation. This often occurs in the cold season,when bone is a good source of essential minerals, such as calcium and sodium, that deer and their cousins cannot procure fromtheir local forests barren midwinter produce section.

In an email, lead author Lauren Meckel, a graduate student at Texas State University, emphasized that the deer caught on camera was not flesh-eating. It was bone-eating, and more specifically, it was dry-bone eating.Carnivores typically go for fresh remains and puncture the bones, whereas ungulates prefer desiccated bonesand leave behind a stripped, forked pattern withtheir zigzagging jaws, the paper notes.

This might actually be useful, and not just grisly, information. While ungulates are not big players inwhat the authors refer to as the scavenging guild, Meckel saidthe Texas discoverycould help investigators who are analyzing human remains determine the cause of bone damage and whether it happened at the time of death or later, perhaps when Bambineeded a calcium boost.

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Bambi's revenge? Deer photographed nibbling on human bones, a ... - Washington Post

In a brutally direct piece in the New York Times on Monday, Sen. John McCain (R-Ariz.) let Secretary of State Rex Tillerson have it for a speech he gave to the State Department in which he argued that national security must take precedence over human rights.

McCain, who grudgingly voted to confirm Tillerson, explained:

Secretary Tillerson sent a message to oppressed people everywhere: Dont look to the United States for hope. Our values make us sympathetic to your plight, and, when its convenient, we might officially express that sympathy. But we make policy to serve our interests, which are not related to our values. So, if you happen to be in the way of our forging relationships with your oppressors that could serve our security and economic interests, good luck to you. Youre on your own.

McCain made a primarily a philosophic argument against Tillersons view. America didnt invent human rights. Those rights are common to all people: nations, cultures and religions cannot choose to simply opt out of them, he wrote. He continued: We are a country with a conscience. We have long believed moral concerns must be an essential part of our foreign policy, not a departure from it. We are the chief architect and defender of an international order governed by rules derived from our political and economic values. We have grown vastly wealthier and more powerful under those rules. More of humanity than ever before lives in freedom and out of poverty because of those rules.

McCain suggested that far from being realists, those who dismiss human rights put U.S. national security at risk. (To view foreign policy as simply transactional is more dangerous than its proponents realize. Depriving the oppressed of a beacon of hope could lose us the world we have built and thrived in. It could cost our reputation in history as the nation distinct from all others in our achievements, our identity and our enduring influence on mankind. Our values are central to all three.)

In more concrete terms, Tillerson and apparently President Trump is giving up a huge advantage on the international stage (our commitment to universal human rights) and handing our enemies a free pass. Didnt Republicans excoriate President Barack Obama for failing to seize the initiative during Irans Green Revolution an effort that might have damaged the regimes credibility and claim to be just another normal nation-state pursuing its own interests? Didnt Republicans blame Obama for failing to stand up for human rights in China, thereby giving up a critical aspect of soft power?

Rex Tillerson on Feb. 1 pledged to "represent the interest of all of the American people" shortly after being sworn in as secretary of state. (The Washington Post)

Frequent Trump critic and former State Department official Eliot A. Cohen provides a guide for Tillerson and others, writing:

One can accept that Egypt will not adopt New England town meetings, but still persistently call out corruption; one can work with Recep Tayyip Erdogan while making clear American abhorrence of what he has done to freedom of the press in a country drifting into Islamist authoritarianism. Indeed, the case of Turkey helps illustrate why the United States should pressprudently but persistentlyfor open and law-abiding societies. They make infinitely better allies in the long run than thugs sitting on powder kegs. . . .

It was an intellectually shallow performance. In many respects, Tillerson said, the Cold War was a lot easier than the world of today. No it was notnot if you worried about nuclear war, were involved in two hot wars that cost an order of magnitude more casualties than the United States suffered in Iraq and Afghanistan, or had to cope with decolonization, local communist movements, and the cultural upheaval of the 1960s.

We won the Cold War, Tillerson should recall, with human rights as a main pillar of our strategy in containing and eventually bringing down the Evil Empire. Human rights was a banner used to rally dissidents and Warsaw Pact countries under the Soviets thumb. We were stronger and the Soviet Union was weaker because of the fundamental difference in outlook with regard to human liberty.

As Cohen warns, support for human rights, In the absence of historical perspective and understanding, foreign policy degenerates into crisis management; in the absence of values-informed and in some cases values-driven policy it can easily slip into short-sighted tactical accommodations, the equivalent of playing chess one move at a time, which is a good way to get mated. He added that it is not any more reassuring that the secretary thanked those sending him one-page memoranda because Im not a fast reader. That is becomingly modest, but the truth is, it is no great qualification for an office that demands intellectual depth.

McCain and Cohen should keep up the tutorials for the benefit of the administration, but its also just as important for the voters and Congress, who must in the absence of presidential leadership continue to defend the United States commitment to universal human rights.

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Tillerson should listen to McCain on human rights - Washington Post (blog)

Kathleen Foody, Associated Press

ATLANTA (AP) As the Trump administration signals a de-emphasis of human rights in U.S. foreign policy decisions, former U.S. President Jimmy Carter said Tuesday that he's concerned America's approach will erode support for such rights in other countries.

The 92-year-old Carter spoke with The Associated Press amid a two-day meeting of dozens of human rights activists at The Carter Center in Atlanta.

Carter cited a portion of President Donald Trump's inaugural address promising that his administration does "not seek to impose our way of life on anyone, but rather to let it shine as an example for everyone to follow." Secretary of State Rex Tillerson expanded on that slightly last week when he told State Department employees that some national security efforts can't always be conditioned on "our values."

"The president made this clear in his inaugural address I was there when he said that no longer would we try to force American standards on other countries," Carter said. "And I assumed that meant the standards of peace and human rights and freedom and justice and that sort of thing. Our standards that we've always claimed to be American standards are really the implementation of a universal declaration of human rights, plus peace."

Carter also challenged the idea that a commitment to human rights can't coexist with national security, calling it a "false premise."

Carter fears global effect of new US human rights policies

"The best way for a nation to guarantee security, absence from fear and absence from violence, is to promote human rights and freedom," he said.

Carter has worked on various human rights issues, from fair elections to health care, since leaving the White House and forming the nonprofit. This year's forum on human rights is the 10th held since 2003, bringing together activists from around the globe.

"They come to tell their stories collectively and also to form an alliance with people around the world who are joined with them in a collective effort to promote the standards of human rights," Carter said. "And to make sure the world doesn't forget that the basic moral values and ethical standards of human beings are being abandoned or ignored in many societies."

The participants share strategies and stories with one another, interspersed with spirited musical performances or videos featuring participants' work. The event also gives The Carter Center and other organizations "a fairly good picture of what's going on in the entire world," Carter said.

Maryam Al-Khawaja, a Bahraini activist who has been imprisoned for her work, said repressive governments learn from each other, and activists need to make connections and work across borders. If there's muted international backlash to a policy in one country limiting human rights work, others will adopt it without fear of consequences, she said.

"We need to put up a challenge and do the same," she said.

Beyond the opportunity to share ideas and make connections, the event provides emotional support for people whose work puts them in constant danger, said Rubina Bhatti, an activist focused on the rights of women and religious minorities in Pakistan. Her organization was shut down by authorities last year.

"When we come to these points, we find a lot of struggle but also strength, solidarity, passion, compassion, love," Bhatti said. "I am not alone in this ocean; we all are trying to swim."

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Carter fears global effect of new US human rights policies - CT Post