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University of California – San Francisco—The human cerebral cortex contains 16 billion neurons, wired together into arcane, layered circuits responsible for everything from our ability to walk and talk to our sense of nostalgia and drive to dream of the future. In the course of human evolution, the cortex has expanded as much as 1,000-fold, but how this occurred is still a mystery to scientists.

Now, researchers at UC San Francisco have succeeded in mapping the genetic signature of a unique group of stem cells in the human brain that seem to generate most of the neurons in our massive cerebral cortex.

The new findings, published Sept. 24, 2015 in the journal Cell, support the notion that these unusual stem cells may have played an important role in the remarkable evolutionary expansion of the primate brain.

“We want to know what it is about our genetic heritage that makes us unique,” said Arnold Kriegstein, MD, PhD, professor of developmental and stem cell biology and director of the Eli and Edyth Broad Center of Regeneration Medicine and Stem Cell Research at UCSF. “Looking at these early stages in development is the best opportunity to understand our brain’s evolution.”

Building a Brain from the Inside Out

The grand architecture of the human cortex, with its hundreds of distinct cell types, begins as a uniform layer of neural stem cells and builds itself from the inside out during several months of embryonic development.

Until recently, most of what scientists knew about this process came from studies of model organisms such as mice, where nearly all neurons are produced by stem cells called ventricular radial glia (vRGs) that inhabit a fertile layer of tissue deep in the brain called the ventricular zone (VZ). But recent insights suggested that the development of the human cortex might have some additional wrinkles.

In 2010, Kriegstein’s lab discovered a new type of neural stem cell in the human brain, which they dubbed outer radial glia (oRGs) because these cells reside farther away from the nurturing ventricles, in an outer layer of the subventricular zone (oSVZ). To the researchers’ surprise, further investigations revealed that during the peak of cortical development in humans, most of the neuron production was happening in the oSVZ rather than the familiar VZ.

oRG stem cells are extremely rare in mice, but common in primates, and look and behave quite differently from familiar ventricular radial glia. Their discovery immediately made Kriegstein and colleagues wonder whether this unusual group of stem cells could be a key to understanding what allowed primate brains to grow to their immense size and complexity.

“We wanted to know more about the differences between these two different stem cell populations,” said Alex Pollen, PhD, a postdoctoral researcher in Kriegstein’s lab and co-lead author of the new study. “We predicted oRGs could be a major contributor to the development of the human cortex, but at first we only had circumstantial evidence that these cells even made neurons.”

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 Drawing of the cerebral cortex. Wikimedia Commons, Wellcome Images

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Outsider Stem Cells Make Their Own Niche

In the new research, Pollen and co-first author Tomasz Nowakowski, PhD, also a postdoctoral researcher in the Kriegstein lab, partnered with Fluidigm Corp. to develop a microfluidic approach to map out the transcriptional profile – the set of genes that are actively producing RNA – of cells collected from the VZ and SVZ during embryonic development.

They identified gene expression profiles typical of different types of neurons, newborn neural progenitors and radial glia, as well as molecular markers differentiating oRGs and vRGs, which allowed the researchers to isolate these cells for further study.

The gene activity profiles also provided several novel insights into the biology of outer radial glia. For example, researchers had previously been puzzled as to how oRG cells could maintain their generative vitality so far away from the nurturing VZ. “In the mouse, as cells move away from the ventricles, they lose their ability to differentiate into neurons,” Kriegstein explained.

But the new data reveals that oRGs bring a support group with them: The cells express genes for surface markers and molecular signals that enhance their own ability to proliferate, the researchers found.

“This is a surprising new feature of their biology,” Pollen said. “They generate their own stem cell niche.”

The researchers used their new molecular insights to isolate oRGs in culture for the first time, and showed that these cells are prolific neuron factories. In contrast to mouse vRGs, which produce 10 to 100 daughter cells during brain development, a single human oRG can produce thousands of daughter neurons, as well as glial cells–non-neuronal brain cells increasingly recognized as being responsible for a broad array of maintenance functions in the brain.

New Insights into Brain Evolution, Development and Disease

The discovery of human oRGs’ self-renewing niche and remarkable generative capacity reinforces the idea that these cells may have been responsible for the expansion of the cerebral cortex in our primate ancestors, the researchers said.

The research also presents an opportunity to greatly improve techniques for growing brain circuits in a dish that reflect the true diversity of the human brain, they said. Such techniques have the potential to enhance research into the origins of neurodevelopmental and neuropsychiatric disorders such as microcephaly, lissencephaly, autism and schizophrenia, which are thought to affect cell types not found in the mouse models that are often used to study such diseases.

The findings may even have implications for studying glioblastoma, a common brain cancer whose ability to grow, migrate and hack into the brain’s blood supply appears to rely on a pattern of gene activity similar to that now identified in these neural stem cells.

“The cerebral cortex is so different in humans than in mice,” Kriegstein said. “If you’re interested in how our brains evolved or in diseases of the cerebral cortex, this is a really exciting discovery.”

The study represents the first salvo of a larger BRAIN Initiative-funded project in Kriegstein’s lab to understand the thousands of different cell types that occupy the developing human brain.

“At the moment, we simply don’t have a good understanding of the brain’s ‘parts list,'” Kriegstein said, “but studies like this are beginning to give us a real blueprint of how our brains are built.”

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Source: University of California-San Francisco press release.

Major funding for the research was provided by the National Institutes of Health, the UCSF Clinical and Translational Science Institute, and the Damon Runyon Cancer Research Foundation.

Additional authors on the study are Jiadong Chen, PhD; Hanna Retallack; Carmen Sandoval-Espinosa; Cory Nicholas, PhD; S. John Liu; Michael Oldham, PhD; Aaron Diaz, PhD; and Daniel Lim, MD, PhD, all of UCSF; and Anne Leyrat, PhD; Joe Shuga, PhD; and Jay West, PhD, of Fluidigm Corp. Nicholas is now at Neurona Therapeutics. Leyrat, Shuga and West declare a financial interest in Fluidigm Corp. as employees and/or stockholders.

UC San Francisco (UCSF) is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes top-ranked graduate schools of dentistry, medicine, nursing and pharmacy, a graduate division with nationally renowned programs in basic, biomedical, translational and population sciences, as well as a preeminent biomedical research enterprise and two top-ranked hospitals, UCSF Medical Center and UCSF Benioff Children’s Hospital San Francisco. Please visit http://www.ucsf.edu.

Cover photo: Wikimedia Commons, http://wellcomeimages.org/indexplus/obf_images/59/92/da8e89c7c8f6dc66400920168f1c.jpg

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Read more in-depth articles about archaeology with a premium subscription to Popular Archaeology Magazine. 

In addition, the latest Popular Archaeology ebook is now available.

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Travel and learn with Far Horizons.

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This richly illustrated ebook version of a recent Popular Archaeology issue includes the following stories: The discovery of the tomb of a previously unknown pharaoh that is shedding light on a lost ancient Egyptian dynasty; how genetics is revolutionizing what we know about human evolution and our prehistoric past; one scholar’s controversial ‘New Chronology’ and how it supports the historicity of the biblical Exodus; how archaeologists are unearthing new history in Williamsburg, Virginia, a seat of British colonial power in 18th century America; the discovery of the remains of a major Roman legionary base in Israel; the unearthing of an ancient Judean fortified settlement in the borderlands between the biblical kingdoms of ancient Judah and the Philistines; and how archaeologists are uncovering evidence of what may have been an important administrative center of Judah during the 8th century BCE. Now available from Amazon.com!

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Petra.  Masada.  Herodium.  Jericho.  Qumran.

These are “Holy Land” archaeological sites of which most of us have heard but comparatively few of us have actually visited in person. There are obvious reasons for that—cost, time, cost, other commitments, cost, other priorities, cost. For those of us who have a passion for things archaeological, especially as they apply to the biblical account and the Middle East in general, such places remain mostly uncrossed on the travel wish list.

But what if you were told that you could ‘visit’ these places without incurring the fortune of airfare, hotel expenses and food, without ever having to hassle with security check lines, step onto an airplane or ride a bus or take a taxi?

One website, called the Virtual World Project, can do that for us. Featuring archaeological sites from Abu Ghosh to Zohar, the website offers virtual grand tours of no less than 106 sites.

Want to walk through the famous mountaintop fortress of Masada, one of the architectural wonders built by the infamous King Herod and the historic last enclave of rebel Jewish forces during the First Jewish Revolt against the Romans? Feeling like strolling through the desert ruins of Qumran, the ancient community thought to have connections to the Dead Sea Scrolls? Having an urge to wander through the remarkable, iconic remains of the ancient city of Petra?

If this sounds like a commercial, in a sense you would be right. But the architects of this website receive no compensation for sharing this experience with the public. Conceived and constructed by Ronald Simkins and Nicolae Roddy, both professors at Creighton University in Omaha, Nebraska, the website was intended largely as an educational tool for students, offering not only interactive panning views of the sites, but also text about each site to inform the viewer. A salient feature of the website is the convenient control it affords the site visitors to tailor their own walking itineraries through each site, and the easy opportunity to tour many other sites of which most visitors may never have even heard.  Ever hear of Iraq al-Amir? Located about 17 kilometers west of Amman, Jordan, the monumental remains of this Hellenistic palace locally called Qasr al-Abd, built by Hyrcanus the Tobiad more than a century before the birth of Jesus, will no doubt impress you.  It is an example of scores of sites most of us wouldn’t think of listing on our travel itineraries.

But enough said.

As they say, a picture is worth a thousand words, so without further ado, here is the website for your perusal.

Bon voyage.

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 The remains of Qasr al-Abd at Iraq al-Amir, Jordan. Image credit Ronald Simkins and Nicolae Roddy, the Virtual World Project.

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The temple at Omrit: Less known than some of King Herod’s other monumental projects, the remains of a Roman temple overlooking today’s Hula valley in northeastern Israel stands as a visual reminder of Herod’s heady days of massive construction works. Also viewable in detail at the Virtual World Project website. Image credit Ronald Simkins and Nicolae Roddy, the Virtual World Project.

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Read more in-depth articles about archaeology with a premium subscription to Popular Archaeology Magazine. 

In addition, the latest Popular Archaeology ebook is now available.

 ______________________________________________

Travel and learn with Far Horizons.

____________________________________________

This richly illustrated ebook version of a recent Popular Archaeology issue includes the following stories: The discovery of the tomb of a previously unknown pharaoh that is shedding light on a lost ancient Egyptian dynasty; how genetics is revolutionizing what we know about human evolution and our prehistoric past; one scholar’s controversial ‘New Chronology’ and how it supports the historicity of the biblical Exodus; how archaeologists are unearthing new history in Williamsburg, Virginia, a seat of British colonial power in 18th century America; the discovery of the remains of a major Roman legionary base in Israel; the unearthing of an ancient Judean fortified settlement in the borderlands between the biblical kingdoms of ancient Judah and the Philistines; and how archaeologists are uncovering evidence of what may have been an important administrative center of Judah during the 8th century BCE. Now available from Amazon.com!

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Cell Press—If you go back far enough, all people share a common ancestry. But some populations are more closely related than others based on events in the past that brought them together. Now, researchers* reporting in the Cell Press journal Current Biology on September 17 have shown that it’s possible to use DNA evidence as a means to reconstruct and date those significant past events. The findings suggest that evidence in our genomes can help to recover lost bits of history.

“We now have the statistical machinery to uncover which historical events have produced the mosaic genomes of people in Europe today,” says George Busby of the University of Oxford. “The successful reconstruction of the genetic history of a region of the world that has been well investigated both archaeologically and historically suggests that these approaches have the potential to be applied to areas where history has not been so well recorded and where genetics might be the only way of recovering history.”

Busby and his colleagues applied a new method they’ve developed to compare single genetic variants among populations, taking into account the relationships among those markers based on their physical proximity along the chromosomes. That information can be used to infer subtle relationships among populations, including those that are genetically very similar, as well as the history of a continent.

The new work shows that all European populations have mixed over time as people picked up and moved from one place to another. Usually this mixing has involved nearby groups, but sometimes populations bear the mark of invading populations from more distant locations.

“Much as different cultures have often borrowed elements from each other, we are now seeing that the genomes of people alive in Europe today contain ancestry from multiple different places, from within Europe and outside,” says Cristian Capelli, the study’s senior author.

The results offer interesting insights into human history, including the lives of “regular people.”

“History is often written by the winners and the elites—we often do not hear about the everyday life of people,” Busby says. “By studying the DNA of populations and understanding how different groups are ancestrally related to each other, our analysis tells the story of all people.”

For example, the researchers found evidence of contact across Central Asia with groups from Mongolia. In fact, they see evidence that Mongolians migrated into Europe in two waves: once at a time that matches the known expansions of Genghis Khan and the other occurring much earlier, prior to 1000 CE in groups of North East Europe, including the Chuvash, Russians, and Mordovians.

The researchers also see evidence of mixing among Europeans in the Mediterranean and people from West and North Africa at many times and places over the course of history. The Slavic expansion also left its mark on European genomes, showing that this was a key event in the genetic history of the region.

The researchers say it’s now “clear that migration and admixture have been the norm, rather than the exception, throughout human history.”

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Gene flow within West Eurasia is shown by lines linking the best-matching donor group to the sources of admixture with recipient clusters (arrowhead). Line colors represent the regional identity of the donor group, and line thickness represents the proportion of DNA coming from the donor group. Ranges of the dates (point estimates) for events involving sources most similar to selected donor groups are shown.  Credit:  Busby et al./Current Biology 2015

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This research was supported by the University of Oxford, the Wellcome Trust, the Royal Society, the Biotechnology and Biological Sciences Research Council, and the British Academy. Co-author James Wilson is a shareholder, employee, and director of the commercial genetic ancestry testing company ScotlandsDNA.

*Current Biology, Busby et al.: “The Role of Recent Admixture in Forming the Contemporary West Eurasian Genomic Landscape” http://dx.doi.org/10.1016/j.cub.2015.08.007

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Read more in-depth articles about archaeology with a premium subscription to Popular Archaeology Magazine. 

In addition, the latest Popular Archaeology ebook is now available.

 ______________________________________________

Travel and learn with Far Horizons.

____________________________________________

This richly illustrated ebook version of a recent Popular Archaeology issue includes the following stories: The discovery of the tomb of a previously unknown pharaoh that is shedding light on a lost ancient Egyptian dynasty; how genetics is revolutionizing what we know about human evolution and our prehistoric past; one scholar’s controversial ‘New Chronology’ and how it supports the historicity of the biblical Exodus; how archaeologists are unearthing new history in Williamsburg, Virginia, a seat of British colonial power in 18th century America; the discovery of the remains of a major Roman legionary base in Israel; the unearthing of an ancient Judean fortified settlement in the borderlands between the biblical kingdoms of ancient Judah and the Philistines; and how archaeologists are uncovering evidence of what may have been an important administrative center of Judah during the 8th century BCE. Now available from Amazon.com!

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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 “Rising Star” cave system in South Africa. Long a caving destination for spelunkers, the Rising Star system is part of a complex of limestone caves near what is called “The Cradle of Humankind,” a World Heritage Site in Gauteng province well known for critical paleoanthropological discoveries of early humans. But at any level, this particular discovery was an extremely rare event. Then, after meticulous analysis of the bones, this international team of 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.

Designated as the “Dinaledi Chamber”, the finds within have gone 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, this creature exhibited a short, ape-like torso and 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 in Africa to date.

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Anthropologist Marina Elliott (left) and paleontologist Ashley Kruger explore a side chamber in the Rising Star cave where more than 1,500 fossil elements of a new species, Homo naledi, were discovered. Elliott was one of six scientists, described as “underground astronauts,” with the skill and physique to reach the remote chamber. National Geographic Explorer-in-Residence Lee Berger of the University of the Witwatersrand (pictured on the computer screen) led the expedition and followed the progress inside the cave from the surface. Photo by Elliot Ross/National Geographic

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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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 Homo naledi skull compared to those of other Homo species. Chris Stringer, Wikimedia Commons

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Skeletal fossils of the hand of Homo naledi pictured in the Wits bone vault at the Evolutionary Studies Institute at the University of the Witwatersrand, Johannesburg, South Africa, on Sept. 13, 2014. The fossil hand is one of many fossils representing a new species of hominin. The broad thumb of Homo naledi suggests it was an expert climber. The Rising Star Expedition, a project that retrieved and analyzed the fossils was led in part by paleoanthropologist John Hawks, professor of anthropology at the University of Wisconsin-Madison. Photo by John Hawks/University of Wisconsin-Madison

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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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A reconstruction of Homo naledi’s head by paleoartist John Gurche, who spent some 700 hours recreating the head from bone scans. Photo by Mark Thiessen/National Geographic

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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, and the age ranges of the skeletons fit the pattern of what archaeologists find in cemeteries. “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.) “It seems probable that a group of hominins was returning to this place over a period of time and depositing bodies,” Hawks explains, adding that the supposition is akin to discovering similar behavior in chimpanzees. “It would be that surprising.” Furthermore, the way the bodies are arranged and their completeness suggests they were carried to the cave intact. “The bodies were not intentionally covered and we’re not talking about a religious ceremony, but something that was repeated and repeated in the same place. They clearly learned to do this and did it as a group over time. That’s cultural. Only humans and close relatives like Neandertals do anything like this.”

The million dollar question: How old?

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

Dating the finds have been problematic for a number of reasons. First, 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. Secondly, 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.”

Thus the consensus at this point is that it is anybody’s guess. “They could have been there 2 million years ago or 100,000 years ago, possibly coexisting with modern humans,” said Hawks. 

One hope, says Hawks, is finding the remains of an animal that may have been a contemporary of Homo naledi. The fossils are embedded in a matrix of soft sediment and there are layers that remain unexcavated.

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. The fossils were thought at the time to be the remains of a single individual. 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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A cross-section showing the Dinaledi chamber within the Rising Star cave near Johannesburg, South Africa, where the fossils of a new species, Homo naledi, were discovered. A team of six “underground astronauts” navigated the extremely narrow chutes to recover more than 1,500 fossil elements discovered in the cave. Jason Treat, National Geographic, Source: Lee Berger, Wits

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Caver Steven Tucker squeezes through a narrow passage in the Rising Star cave. Tucker was one of the cavers on Lee Berger’s exploration team who found the chamber where H. naledi, a new species of human relative, was discovered. Photo by Garrreth Bird

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“Underground astronauts” Marina Elliott and Becca Peixotto work inside the cave where fossils of H. naledi, a new species of human relative, were discovered. Photo by Garrreth Bird

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The “underground astronauts” (left to right): Becca Peixotto, Alia Gurtov, Elen Feuerriegel, Marina Elliott, K. Lindsay (Eaves) Hunter and Hannah Morris. The team of scientists excavated the chamber where H. naledi, a new species of human relative, was discovered. Photo by John Hawks

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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. The developing picture, in other words, may be becoming enormously complex, with the possibility of a multitude of various hominin species inhabiting the same regions and perhaps even interbreeding, creating what Berger has described as a “braided stream” through time to Home sapiens (modern humans), as opposed to the traditional, linear model advanced by earlier scientists. And as more evidence emerges, more questions are raised.   

For now, much remains to be discovered in the Rising Star cave alone. “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.”

According to Hawks, years of work remain at the site, including continuing analysis and documentation of all of the materials excavated. Plans, he says, include bringing many new technologies to bear on analyzing the fossils to help determine diet, rate of aging, and where they lived on the landscape. 

Readers can find out more in the detailed study reports in eLife.

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*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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The discovery is featured as the cover story of National Geographic magazine’s October 2015 issue, available online now and on print newsstands starting September 29, 2015. The NOVA/National Geographic Special, “Dawn of Humanity,” premieres September 16, 2015, at 9 p.m. ET/8 p.m. CT on PBS in the United States and is streaming online now. The program will air outside of the United States later in September. You can follow the conversation using #NalediFossils. 

See more videos about this discovery like the one shown in this article at PBS.org at  http://www.pbs.org/wgbh/nova/evolution/dawn-of-humanity.html. 

The research was supported by Wits University, the National Geographic Society and South African DST/NRF. Ongoing exploration and conservation of the Rising Star site is supported by the Lyda Hill Foundation.

Portions of this article were adapted and edited from sections of subject press releases of the University of the Witwatersrand, New York University, and the University of Wisconsin, Madison.

Cover Image for this article: Photo by Mark Thiessen/National Geographic

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Read more in-depth articles about archaeology with a premium subscription to Popular Archaeology Magazine. 

In addition, the latest Popular Archaeology ebook is now available.

 ______________________________________________

Travel and learn with Far Horizons.

____________________________________________

This richly illustrated ebook version of a recent Popular Archaeology issue includes the following stories: The discovery of the tomb of a previously unknown pharaoh that is shedding light on a lost ancient Egyptian dynasty; how genetics is revolutionizing what we know about human evolution and our prehistoric past; one scholar’s controversial ‘New Chronology’ and how it supports the historicity of the biblical Exodus; how archaeologists are unearthing new history in Williamsburg, Virginia, a seat of British colonial power in 18th century America; the discovery of the remains of a major Roman legionary base in Israel; the unearthing of an ancient Judean fortified settlement in the borderlands between the biblical kingdoms of ancient Judah and the Philistines; and how archaeologists are uncovering evidence of what may have been an important administrative center of Judah during the 8th century BCE. Now available from Amazon.com!

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UNIVERSITY OF CAMBRIDGE— New stable isotope and ancient DNA analysis of the bones of stored cod provisions recovered from the wreck of the Tudor warship Mary Rose, which sank off the coast of southern England in 1545, has revealed that the fish in the ship’s stores had been caught in surprisingly distant waters: the northern North Sea and the fishing grounds of Iceland – despite England having well developed local fisheries by the 16th century.

Test results from one of the sample bones has led archaeologists to suspect that some of the stored cod came from as far away as Newfoundland in eastern Canada.

The research team say that the findings show how naval provisioning played an important role in the early expansion of the fish trade overseas, and how that expansion helped fuel the growth of the English navy. Commercial exploitation of fish and the growth of naval sea power were “mutually reinforcing aspects of globalisation” in Renaissance Europe, they say.

“The findings contribute to the idea that the demand for preserved fish was exceeding the supply that local English and Irish fisheries were able to provide in order to feed growing – and increasingly urban – populations. We know from these bones that one of the sources of demand was naval provisions,” said Dr James Barrett, from the McDonald Institute for Archaeological Research at the University of Cambridge.

“The existence and development of globalised fisheries was one of the things that made the growth of the navy possible. The navy was a key mechanism of maritime expansion, while at the same time being sustained by that expansion. The story of the cod trade is a microcosm of globalisation during this pivotal period that marked the beginning of an organised English navy, which would go on to become the Royal Navy,” he said.

The study, led by researchers from the universities of Cambridge, Hull and York, is published today in the open access journal Royal Society Open Science.

Built in 1510, the Mary Rose was one of the most famous ships in England, a former flagship of Henry VIII’s fleet, when it mysteriously heeled over and sank in the Solent channel during a battle with an invading French fleet in 1545, taking almost all of its crew – over 400 men – down with it, as well as a full store of provisions. Rediscovered in the 1970s and raised in 1982, the remains are an extraordinary time capsule of naval life during the Tudor period.

Among the remains of the ship’s supplies were thousands of bones from dried or salted cod from casks and baskets – staples of Tudor naval diet. The researchers took a small selection of eleven bones from the various different holds of the ship, and analysed them using two techniques: stable isotope analysis, which reflects the diet and environmental conditions of the fish based on the bone’s protein chemistry, and ancient DNA analysis, which reflects genetic drift, gene flow and natural selection.

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These are cod bones (cleithra) recovered from the Mary Rose, with a stained modern example for comparison. Credit: Sheila Hamilton-Dyer

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These are cod bones (vertebrae) recovered from the Mary Rose. Credit: Sheila Hamilton-Dyer

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Separately, the techniques gave very broad answers, but when cross-referenced with each other and the historical record they provided researchers with increasingly reliable evidence for which waters the cod had been fished from almost 500 years ago.

The best indication for three of the samples was that they were fished in the northern North Sea, possibly the Scottish Northern Isles, where there were known fisheries that produced dried cod preserved in salt.

Another seven of the samples probably came from waters off the cost of Iceland. Due to the cold and dry climate, many Icelanders preserved cod by air-drying it during winter months, a product known as ‘stockfish’, which was frequently traded with the English. English fishermen also worked Icelandic waters themselves, to produce salt cod. At the time, England to Iceland was a three to six month round trip, usually departing in spring and returning in early autumn after a season of trade and/or fishing.

One bone sample appeared to have come from the other side of the Atlantic. While not definitive, the most likely evidence pointed to Newfoundland, an island off the northeast Canadian coast famous for its historical cod fishery. While such distances for fishing may seem surprising for the time, James Barrett says that – as the English Newfoundland fishery had begun in 1502, in the wake of John Cabot’s exploratory voyage of 1497 – this is entirely plausible. French, Spanish and Portuguese fishermen also took advantage of this new source of cod.

“At the time of the Mary Rose in 1545, Newfoundland was a small-scale seasonal fishery where mariners went to fish and then come home. Within a century the Newfoundland fishery had become a major economic concern, of greater value than the fur trade, for example,” said Barrett.

“The need for fish stocks was an important driver of involvement in north-eastern North America. The fish trade was one of the key links in the causal chain of European expansion to that continent,” he said. A typical outbound journey time from England to Newfoundland was around five weeks.

Records from just after the time of the Mary Rose show that a standard daily ration of preserved cod was a quarter of a fish served with ship biscuit, two ounces of butter and a gallon of beer. This was dished up three times a week. The bone samples show that these fish could range from approximately 70cm to over a metre in length, so a quarter of cod was a significant portion. “Preserved cod was great value for money as a provision, particularly as space and durability were an issue on board a ship,” said Barrett.

Before the reign of Henry VIII, another driver for the cod fisheries was the fact that fish was a suitable food during Christian fasts such as Lent as an alternative to milk and cheese, and, as Barrett points out, “urban populations didn’t have room for cows in their back yards”.

Once Henry VIII split from the church and the Reformation was ushered in, religious associations with meals of fish started to dissipate, threatening to send England’s fisheries, and subsequently its navy, into decline.

Thus Elizabeth I, Henry’s successor, instigated weekly ‘fish days’ to encourage domestic consumption and consequently a commercial fleet to not only help feed the navy but also ensure a supply of mariners to help run it when needed.

“The importance of ‘victualling’ the navy continued to grow in the seventeenth century, most famously during the Restoration when its administration was systematized under Samuel Pepys,” said Barrett.

“Military sea power was a prerequisite for the concurrent – and subsequent – development of England’s sea-borne colonialism. Yet by sourcing the cod bones from the Mary Rose, we see that the navy itself was first sustained, in part, by fishermen working distant northern and transatlantic waters,” he said.

Arguably the most challenging aspect of the research was creating the historical context, the ‘base map’, for the researchers to compare their Mary Rose specimens to. Due to chemical pollution of the world’s oceans over the last few hundred years, and changes in the genetic structure of cod populations due to fishing pressures and climate change, the team had to find and use ancient cod bones for their study’s comparison controls, as modern cod bones would have been useless.

“Thankfully, when making dried cod, part of the process was chopping the head off,” said Barrett. “This meant we could use skull bones from archaeological sites to get both genetic and isotopic signatures for all these regions. The lion’s share of the work was finding and analysing the over 300 control samples.”

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Source: Subject press release of the University of Cambridge.

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This richly illustrated ebook version of a recent Popular Archaeology issue includes the following stories: The discovery of the tomb of a previously unknown pharaoh that is shedding light on a lost ancient Egyptian dynasty; how genetics is revolutionizing what we know about human evolution and our prehistoric past; one scholar’s controversial ‘New Chronology’ and how it supports the historicity of the biblical Exodus; how archaeologists are unearthing new history in Williamsburg, Virginia, a seat of British colonial power in 18th century America; the discovery of the remains of a major Roman legionary base in Israel; the unearthing of an ancient Judean fortified settlement in the borderlands between the biblical kingdoms of ancient Judah and the Philistines; and how archaeologists are uncovering evidence of what may have been an important administrative center of Judah during the 8th century BCE. Now available from Amazon.com!

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Villagers residing in a swath of land stretching from southern Colorado to northern Chihuahua, Mexico, consumed caffeinated drinks beginning as early as A.D. 750, according to a study. In the years since archaeologists discovered cacao residues in ceramics from Chaco Canyon, New Mexico, researchers have questioned the time depth and geographic extent of cacao exchange between populations in the pre-Hispanic US Southwest/Mexican Northwest and Mesoamerica. Patricia Crown and colleagues used a combination of liquid chromatography and mass spectrometry to analyze organic residues present in 177 ceramic samples recovered from 18 sites in Arizona, Chihuahua, Colorado, and New Mexico. The findings reveal that villagers residing in a swath of land stretching from southern Colorado to northern Chihuahua consumed caffeinated drinks beginning as early as A.D. 750 and extending to at least A.D. 1400. The analysis identified traces of caffeine, theobromine, and theophylline, which are components of stimulant drinks that were most likely concocted from either cacao or holly leaves and twigs. The stimulant drinks were likely consumed during ceremonial occasions rather than on an everyday basis, similar to practices by other North and South American populations during that time. According to the authors, the findings may shed light on relations and trade between geographically distant North American populations.

Details of the study* are published in the Proceedings of the National Academy of Sciences.

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Fourmile Polychrome flowerpot-shaped vessel from Grasshopper Pueblo*. 

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*“Ritual drinks in the pre-Hispanic US Southwest and Mexican Northwest,” by Patricia L. Crown et al., Proceedings of the National Academy of Sciences, 7 September 2015.

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This richly illustrated ebook version of a recent Popular Archaeology issue includes the following stories: The discovery of the tomb of a previously unknown pharaoh that is shedding light on a lost ancient Egyptian dynasty; how genetics is revolutionizing what we know about human evolution and our prehistoric past; one scholar’s controversial ‘New Chronology’ and how it supports the historicity of the biblical Exodus; how archaeologists are unearthing new history in Williamsburg, Virginia, a seat of British colonial power in 18th century America; the discovery of the remains of a major Roman legionary base in Israel; the unearthing of an ancient Judean fortified settlement in the borderlands between the biblical kingdoms of ancient Judah and the Philistines; and how archaeologists are uncovering evidence of what may have been an important administrative center of Judah during the 8th century BCE. Now available from Amazon.com!

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Researchers report early evidence of flour production by ancient humans. Recent interest in ancient diets has led to the collection of extensive data about the variety of plants eaten by early humans and ancient food processing capabilities. Marta Mariotti Lippi of the University of Florence and colleagues analyzed the residues from an ancient grinding tool to gain further insight into food processing practices of the Early Gravettian culture of ancient Europe. The tool was found in Grotta Paglicci in Southern Italy in 1989 and dates to more than 32,000 years ago. Residue samples from the tool contained a variety of starch grains, and the distribution of the starch grains on the tool surface supported the use of the tool for grinding grain into flour. The presence of swollen, gelatinized starch grains in the residues suggests that the plants were thermally treated before grinding. Such a treatment might have been necessary to accelerate plant drying during the Middle-Upper Paleolithic, when the climate was colder than at present. The most common starch grains in the residues appeared to come from oats, representing the oldest evidence to date of the processing of oats for human consumption. The findings suggest that the inhabitants of Grotta Paglicci may have been the earliest people to use a multi-step process in preparing plants for consumption.

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Interior of Grotta Paglicci, Italy, with wall paintings. Image courtesy of Stefano Ricci.

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Grinding stone from Grotta Paglicci, Italy. Image courtesy of Stefano Ricci.

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Swollen, gelatinized starch grain from the Paglicci grinding stone. Image courtesy of Marta Mariotti Lippi.

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The research* has been published in detail in the Proceedings of the National Academy of Sciences.

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“Multistep food plant processing at Grotta Paglicci (Southern Italy) around 32,600 cal B.P.,” by Marta Mariotti Lippi, Bruno Foggi, Biancamaria Aranguren, Annamaria Ronchitelli, and Anna Revedin. Proceedings of the National Academy of Sciences, 7 September 2015.

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This richly illustrated ebook version of a recent Popular Archaeology issue includes the following stories: The discovery of the tomb of a previously unknown pharaoh that is shedding light on a lost ancient Egyptian dynasty; how genetics is revolutionizing what we know about human evolution and our prehistoric past; one scholar’s controversial ‘New Chronology’ and how it supports the historicity of the biblical Exodus; how archaeologists are unearthing new history in Williamsburg, Virginia, a seat of British colonial power in 18th century America; the discovery of the remains of a major Roman legionary base in Israel; the unearthing of an ancient Judean fortified settlement in the borderlands between the biblical kingdoms of ancient Judah and the Philistines; and how archaeologists are uncovering evidence of what may have been an important administrative center of Judah during the 8th century BCE. Now available from Amazon.com!

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