Denisovan DNA found in sediments of Baishiya Karst Cave on Tibetan Plateau

One year after the publication of research on the Xiahe mandible, the first Denisovan fossil found outside of Denisova Cave, the same research team has now reported their findings of Denisovan DNA from sediments of the Baishiya Karst Cave (BKC) on the Tibetan Plateau where the Xiahe mandible was found. 

Baishiya Karst Cave [Credit: HAN Yuanyuan]

The research team was led by Prof. CHEN Fahu from the Institute of Tibetan Plateau Research (ITP) of the Chinese Academy of Sciences (CAS), Prof. ZHANG Dongju from Lanzhou University, Prof. FU Qiaomei from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of CAS, Prof. Svante Paabo from the Max Planck Institute for Evolutionary Anthropology, and Prof. LI Bo from University of Wollongong.

Using cutting-edge paleogenetic technology, the researchers successfully extracted Denisovan mtDNA from Late Pleistocene sediment samples collected during the excavation of BKC. Their results show that this Denisovan group is closely related to the late Denisovans from Denisova Cave, indicating Denisovans occupied the Tibetan Plateau for a rather long time and had probably adapted to the high-altitude environment.

Denisovans were first discovered and identified in 2010 by a research team led by Prof. Svante Paabo. Almost a decade later, the Xiahe mandible was found on the Tibetan Plateau. As the first Denisovan fossil found outside of Denisova Cave, it confirmed that Denisovans had occupied the roof of the world in the late Middle Pleistocene and were widespread. Although the Xiahe mandible shed great new light on Denisovan studies, without DNA and secure stratigraphic and archaeological context, the information it revealed about Denisovans was still considerably restricted.

Collecting sediment DNA samples [Credit: HAN Yuanyuan]

In 2010, a research team from Lanzhou University led by Prof. CHEN Fahu, current director of ITP, began to work in BKC and the Ganjia basin where it is located. Since then, thousands of pieces of stone artifacts and animal bones have been found. Subsequent analysis indicated that the stone artifacts were mainly produced using simple core-flake technology. Among animal species represented, gazelles and foxes dominated in the upper layers, but rhinoceros, wild bos and hyena dominated in the lower layers. Some of the bones had been burnt or have cut-marks, indicating that humans occupied the cave for a rather long time.

To determine when people occupied the cave, researchers used radiocarbon dating of bone fragments recovered from the upper layers and optical dating of sediments collected from all layers in the excavated profile. They measured 14 bone fragments and about 30,000 individual grains of feldspar and quartz minerals from 12 sediment samples to construct a robust chronological framework for the site. Dating results suggest that the deepest excavated deposits contain stone artifacts buried over ~190 ka (thousand years). Sediments and stone artifacts accumulated over time until at least ~45 ka or even later.

To determine who occupied the cave, researchers used sedimentary DNA technology to analyze 35 sediment samples specially collected during the excavation for DNA analysis. They captured 242 mammalian and human mtDNA samples, thus enriching the record of DNA related to ancient hominins. Interestingly, they detected ancient human fragments that matched mtDNA associated with Denisovans in four different sediment layers deposited ~100 ka and ~60 ka.

Preparing sediment samples in IVPP cleanroom [Credit: WANG Xiao]

More interestingly, they found that the hominin mtDNA from 60 ka share the closest genetic relationship to Denisova 3 and 4 - i.e., specimens sampled from Denisova Cave in Altai, Russia. In contrast, mtDNA dating to ~100 ka shows a separation from the lineage leading to Denisova 3 and 4.

Using sedimentary DNA from BKC, researchers found the first genetic evidence that Denisovans lived outside of Denisova Cave. This new study supports the idea that Denisovans had a wide geographic distribution not limited to Siberia, and they may have adapted to life at high altitudes and contributed such adaptation to modern humans on the Tibetan Plateau.

However, there are still many questions left. For example, what's the latest age of Denisovans in BKC? Due to the reworked nature of the top three layers, it is difficult to directly associate the mtDNA with their depositional ages, which are as late as 20-30 ka BP. Therefore, it is uncertain whether these late Denisovans had encountered modern humans or not. In addition, just based on mtDNA, we still don't know the exact relationship between the BKC Denisovans, those from Denisova Cave in Siberia and modern Tibetans. Future nuclear DNA from this site may provide a tool to further explore these questions.

The study was published in Science.

Source: Chinese Academy of Sciences [October 30, 2020]

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The traits of Florisbad skull reinforce the mosaic hypothesis of human evolution

Emiliano Bruner, a paleoneurologist at the Centro Nacional de Investigacion sobre la Evolucion Humana (CENIEH), in collaboration with Marlize Lombard, of the University of Johannesburg, has just published a study in the Journal of Anthropological Sciences which describes the braincase traits of Florisbad, a fossil found in South Africa in 1932, and its similarities with other species like Homo sapiens, H. neanderthalensis and H. heidelbergensis.

Florisbad skull [Credit: E. Bruner et al. 2020]

The frontal bone of this individual, dated to around 260,000 years ago, has a completely modern shape, which suggests a spatial relationship between face and cranial vault very similar to that of Homo sapiens, although the frontal lobes are particularly broad, like in H. neanderthalensis. Nonetheless, the parietal bone displays an anatomy very similar to more archaic species such as H. heidelbergensis.

"The Florisbad cranium might be key to investigating the origin of our species. It could be from a very early population of Homo sapiens or an extinct group belonging to another independent, parallel human lineage," says Bruner.

Fossils with a mixture of more highly evolved characters in the face and more primitive ones in the posterior regions of the cranium have also been found in Europe and Asia, which corroborates the idea that human evolution did not proceed linearly but mosaically.

Source: CENIEH [October 30, 2020]

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Plankton turn hunters to survive dinosaur-killing asteroid impact

New research by an international team of scientists shows how marine organisms were forced to 'reboot' to survive following the asteroid impact 66 million years ago which killed three quarters of life on earth.

High-resolution scanning electron microscope (SEM) images of fossil cell coverings of nannoplankton
 (coccolithophores) highlighting holes that would have allowed flagella and haptonema to emerge
from the cell and draw in food particles (red dots). We have shown a reconstruction
of one of these ancient cells based on living coccolithophores and related algae
[Credit: Paul Bown]

Researchers from the University of Southampton and UCL, along with colleagues in Paris, California, Bristol and Edinburgh used an exceptional record of plankton fossils and eco-evolutionary modelling techniques to examine how organisms behaved before and after this extinction event - and why some survived and some didn't.

The team found that prior to the asteroid impact, species of nannoplankton - microscopic algae - were exclusively reliant on harnessing energy from sunlight (photoautotrophs), but those living afterwards were capable of capturing food and eating it in addition to using photosynthesis to feed (mixotrophs). This suggests the blocking of light from the sun played an important role in killing off some species and over time, encouraging others to evolve and adapt.

The research team's breakthrough came when they found that many of the nannoplankton skeletons (coccospheres) post mass-extinction included a large hole, indicating the position of flagella - tiny tail like structures used by the algae for movement and feeding. This indicates these microscopic organisms, which survived the asteroid strike, were capable of hunting and ingesting food.

"Those species that were lost at the mass extinction show no evidence of a mixotrophic lifestyle and were likely to be completely reliant on sunlight and photosynthesis," explains Dr Samantha Gibbs of the University of Southampton. "Fossils following the Cretaceous-Paleogene (K-Pg) extinction show that mixotrophy dominated and our model indicates this is because of the exceptional abundance of small prey cells - most likely surviving bacteria - and reduced numbers of larger 'grazers' in the post-extinction oceans."

A SEM view of a seafloor after the extinction showing the abundance of these cells with flagellar
 openings. These cells are around 7 microns in diameter (7/1000ths of a millimetre) with
the scale bars next to each image showing the size of a micron (1/1000th mm)
[Credit: Paul Bown]

Opposing evolutionary forces led to the emergence of more diverse feeding strategies and eventually a return to greater reliance on photosynthesis in open ocean nannoplankton. Most nannoplankton today only photosynthesise. So, what caused this devastating mass extinction of photoautotrophs and other species?

The simple answer is a lack of light. The K/Pg event was triggered by an asteroid impact that formed the Chicxulub crater in Mexico, and is well known for the extinction of dinosaurs, plesiosaurs, ammonites and many other groups.

"This huge impact flung vast amounts of debris, aerosols and soot into the atmosphere, causing darkness, cooling and acidification over days and years," says Paul Bown, Professor of Micropalaeontology at UCL. "The significant bias found in the nannoplankton extinctions - removal of open-ocean photoautotrophs but survival of mixotrophs that could hunt and feed - can only be fully explained by the darkness caused by the asteroid impact acting as a kill mechanism."

Graphic explaining the research method and findings
[Credit: Gibbs et al., 2020]

Samantha Gibbs adds: "This 'blackout' or shutdown of primary productivity would have been felt across all of Earth's ecosystems and reveals that the K/Pg event is distinct from all other mass extinctions that have shaped the history of life, both in its rapidity, related to an instantaneous impact event, and its darkness kill mechanism, which shook the foundations of the food chains. The K/Pg boundary event likely represents the only truly geologically instantaneous mass extinction event."

Findings are published in the journal Science Advances.

Source: University of South Hampton [October 30, 2020]

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Evidence suggests more mega-droughts are coming

Mega-droughts—droughts that last two decades or longer—are tipped to increase thanks to climate change, according to University of Queensland-led research.

Credit: University of Queensland

UQ's Professor Hamish McGowan said the findings suggested climate change would lead to increased water scarcity, reduced winter snow cover, more frequent bushfires and wind erosion. The revelation came after an analysis of geological records from the Eemian Period—129,000 to 116,000 years ago—which offered a proxy of what we could expect in a hotter, drier world.

"We found that, in the past, a similar amount of warming has been associated with mega-drought conditions all over south eastern Australia," Professor McGowan said. "These drier conditions prevailed for centuries, sometimes for more than 1000 years, with El Nino events most likely increasing their severity."

The team engaged in paleoclimatology—the study of past climates—to see what the world will look like as a result of global warming over the next 20 to 50 years.

"The Eemian Period is the most recent in Earth's history when global temperatures were similar, or possibly slightly warmer than present," Professor McGowan said. "The 'warmth' of that period was in response to orbital forcing, the effect on climate of slow changes in the tilt of the Earth's axis and shape of the Earth's orbit around the sun. In modern times, heating is being caused by high concentrations of greenhouse gasses, though this period is still a good analog for our current-to-near-future climate predictions."

Researchers worked with the New South Wales Parks and Wildlife service to identify stalagmites in the Yarrangobilly Caves in the northern section of Kosciuszko National Park. 

Small samples of the calcium carbonate powder contained within the stalagmites were collected, then analyzed and dated at UQ. That analysis allowed the team to identify periods of significantly reduced precipitation during the Eemian Period.

"They're alarming findings, in a long list of alarming findings that climate scientists have released over the last few decades," Professor McGowan said. "We hope that this new research allows for new insights to our future climate and the risks it may bring, such as drought and associated bushfires. But, importantly, if humans continue to warm the planet, this is the future we may all be looking at."

The study was published in Scientific Reports.

Source: University of Queensland [October 30, 2020]

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How many habitable planets are out there?

Thanks to new research using data from the Kepler space telescope, it's estimated that there could be as many as 300 million potentially habitable planets in our galaxy. Some could even be pretty close, with several likely within 30 light-years of our Sun. The findings will be published in The Astronomical Journal, and research was a collaboration of scientists from NASA, the SETI Institute, and other organizations worldwide.

This illustration depicts one possible appearance of the planet Kepler-452b, the first
near-Earth-size world to be found in the habitable zone of a star similar to our Sun
[Credit: NASA Ames/JPL-Caltech]

"This is the first time that all of the pieces have been put together to provide a reliable measurement of the number of potentially habitable planets in the galaxy," said co-author Jeff Coughlin, an exoplanet researcher at the SETI Institute and Director of Kepler's Science Office. "This is a key term of the Drake Equation, used to estimate the number of communicable civilizations—we're one step closer on the long road to finding out if we're alone in the cosmos."

The Drake Equation is a probabilistic argument that details the factors to consider when estimating the potential number of technologically advanced civilizations in the galaxy that could be detected. The Drake Equation is also often considered to be a roadmap for astrobiology and guides much of the research at the SETI Institute.

To develop a reasonable estimate, the researchers looked at exoplanets similar in size to Earth and thus most likely to be rocky planets. They also looked at so-called Sun-like stars, around the same age as our Sun and approximately the same temperature. Another consideration for habitability is whether the planet could have the conditions necessary to support liquid water.

Previous estimates about determining the number of potentially habitable exoplanets there are in our galaxy were heavily based on the planet's distance from its star. This new research also considers how much light hits the planet from its star, which would impact the likelihood that the planet could support liquid water. To do this, the team looked not only at Kepler data, but also at data from the European Space Agency's Gaia mission about how much energy the planet's star emits.

An illustration representing the legacy of NASA's Kepler space telescope. After nine years in deep
space collecting data that revealed our night sky to be filled with billions of hidden planets –
more planets even than stars – NASA’s Kepler space telescope ran out of fuel needed for
further science operations in 2018 [Credit: NASA/Ames Research Center/W. Stenzel]

By taking both Kepler and Gaia data into account, the results better reflect the diversity of stars, solar systems, and exoplanets in our galaxy.

"Knowing how common different kinds of planets are is extremely valuable for the design of upcoming exoplanet-finding missions," said co-author Michelle Kunimoto, who worked on this paper after finishing her doctorate on exoplanet occurrence rates at the University of British Columbia, and recently joined the Transiting Exoplanet Survey Satellite, or TESS, team at the Massachusetts Institute of Technology in Cambridge, Massachusetts. "Surveys aimed at small, potentially habitable planets around Sun-like stars will depend on results like these to maximize their chance of success."

More research will be needed to understand the role a planet's atmosphere has on its capacity to support liquid water. In this analysis, researchers used a conservative estimate of the atmosphere's effect to estimate the occurrence of Sun-like stars with rocky planets that could have liquid water.

The Kepler mission, which officially ceased collecting data in 2018, has identified over 2,800 confirmed exoplanets, with several thousand more candidates waiting to be confirmed. So far, researchers have identified several hundred planets in the habitable zone of their star in Kepler data. It may take a while to find all 300 million!

Source: SETI Institute [October 30, 2020]

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Assessing the habitability of planets around old red dwarfs

A new study using data from NASA's Chandra X-ray Observatory and Hubble Space Telescope gives new insight into an important question: how habitable are planets that orbit the most common type of stars in the Galaxy? The target of the new study, as reported in our press release, is Barnard's Star, which is one of the closest stars to Earth at a distance of just 6 light years. Barnard's Star is a red dwarf, a small star that slowly burns through its fuel supply and can last much longer than medium-sized stars like our Sun. It is about 10 billion years old, making it twice the age of the Sun.

Credit: Chandra X-ray Center

The authors used Barnard's Star as a case study to learn how flares from an old red dwarf might affect any planets orbiting it. This artist's illustration depicts an old red dwarf like Barnard's Star (right) and an orbiting, rocky planet (left).

The research team's Chandra observations of Barnard's Star taken in June 2019 uncovered one X-ray flare (shown in the inset box) and their Hubble observations taken in March 2019 revealed two ultraviolet high-energy flares (shown in an additional graphic). Both observations were about seven hours long and both plots show X-ray or ultraviolet brightness extending down to zero. Based on the length of the flares and of the observations, the authors concluded that Barnard's Star unleashes potentially destructive flares about 25% of the time.

The team then studied what these results mean for rocky planets orbiting in the habitable zone—where liquid water could exist on their surface—around an old red dwarf like Barnard's Star. Any atmosphere formed early in the life of a habitable-zone planet was likely to have been eroded away by high-energy radiation from the star during its volatile youth. Later on, however, planet atmospheres might regenerate as the star becomes less active with age. This regeneration process may occur by gases released by impacts of solid material or gases being released by volcanic processes.

However, the onslaught of powerful flares like those reported here, repeatedly occurring over hundreds of millions of years, may erode any regenerated atmospheres on rocky planets in the habitable zone. The illustration shows the atmosphere of the rocky planet being swept away to the left by energetic radiation from flares produced by the red dwarf. This would reduce the chance of these worlds supporting life. The team is currently studying high-energy radiation from many more red dwarfs to determine whether Barnard's Star is typical.

A paper describing these results was published in The Astronomical Journal.

Source: NASA [October 30, 2020]

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2,000-year old seal bearing portrait of Apollo found in Jerusalem

A gem was found in the The Archaeological Sifting Project in the Tzurim Valley National Park, carried out under the auspices of the City of David and the Nature and Parks Authority. The gem features an engraved portrait of the god Apollo. According to researchers, this rare find is the third secured gem sealing (also called an intaglio which is a gem with a design carved into the upper side of the stone) from the Second Temple period to have ever been discovered in Jerusalem. 

This 2,000-year-old gem seal bearing the image of Apollo was found in earth excavated
from the foundations of the Western Wall in the Old City of Jerusalem
[Credit: Eliyahu Yanai, City of David]

The gem is cut from dark brown jasper, and has remnants of yellow-light, brown, and white layers. In antiquity, jasper was considered a precious stone. The gem seal was embedded in a ring, dated to the 1st century CE (Second Temple period).

The gem is tiny, oval-shaped, 13 mm long, 11 mm wide, and 3 mm thick. Because the gem is an intaglio, its main function was as a stamp to be used on soft material, usually beeswax, for personal signatures on contracts, letters, wills, goods or bundles of money. The gem features an engraving of Apollo’s head in profile to the left, with long hair flowing over a wide, pillar-like neck, a large nose, thick lips, and a small prominent chin. The hair is styled in a series of parallel lines directed to the apex, and surrounded by a braid above the forehead. One line of hair marks a strand that covers the ear; long curls flow over part of the neck, reaching the left shoulder. Thin diagonal lines at the base of the head mark the upper end of the garment and the body.

Credit: Eliyahu Yanai, City of David

According to researchers - archaeologist Eli Shukron, Prof. Shua Amorai-Stark, and senior archaeologist Malka Hershkovitz - although Apollo is an Olympian deity of the Greek and Roman cultures, it is highly probable that the person wearing the ring was a Jew.

In the opinion of archaeologist Eli Shukron, who conducted the excavation in which the gem was found: “It is rare to find seal remains bearing the image of the god Apollo at sites identified with the Jewish population. To this day, two such gems (seals) have been found in Masada, another in Jerusalem inside an ossuary (burial box) in a Jewish tomb on Mount Scopus, and the current gem that was discovered in close proximity to the Temple Mount.” Mr. Shukron added: “When we found the gem, we asked ourselves ‘what is Apollo doing in Jerusalem? And why would a Jew wear a ring with the portrait of a foreign god?’ The answer to this, in our opinion, lies in the fact that the owner of the ring wore it not as a ritual act that expresses religious belief, but as a means of making use of the impact that Apollo’s figure represents: light, purity, health, and success.”

Prof. Shua Amorai-Stark, a researcher of engraved gems, stated that: “At the end of the Second Temple period, the sun god Apollo was one of the most popular and revered deities in Eastern Mediterranean regions. Apollo was a god of manifold functions, meanings, and epithets. Among Apollo’s spheres of responsibility, it is likely that association with sun and light (as well as with logic, reason, prophecy, and healing) fascinated some Jews, given that the element of light versus darkness was prominently present in Jewish worldview in those days. The fact that the craftsman of this gem left the yellow-golden and light brown layers on the god’s hair probably indicates a desire to emphasize the aspect of light in the god’s persona, as well as in the aura that surrounded his head. The choice of a dark stone with yellow coloring of hair suggests that the creator or owner of this intaglio sought to emphasize the dichotomous aspect of light and darkness and/or their connectedness.”

Source: City of David [October 29, 2020]

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Spanish farmer finds 3,000 years old lion sculpture while ploughing his olive grove

On a farm in Cañablanquilla, near San Sebastián de los Ballesteros (Córdoba, Spain), farmer Gonzalo Crespo was working in the family olive grove when his tractor hit what he thought was a large stone. When he stopped to inspect what it was he had hit, he was amazed to see a large statue of a lioness capturing her prey.

Credit: Seprona

Immediately after the discovery, Crespo called the Civil Guard and members of the Seprona presented themselves together with other technicians  from the Delegation of Culture of the Junta de Andalucía. 

Credit: AJ Gonzalez

The large sculpture is in perfect condition and according to archaeologists could be 3,000 years old. It was subsequently moved to the Archaeological Museum of Cordoba to be cleaned and examined. 

Credit: AJ Gonzalez

According to Francisco Javier Maestro, mayor of San Sebastián de los Ballesteros, although there are documented vestiges of the Roman era in the municipality, this is the first time that an archaeological find of such importance has been made.

Source: Diario Cordoba [trsl. TANN, October 29, 2020]

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Archaeologists reveal human resilience in face of climate change in Northern Levant during Bronze Age

An examination of two documented periods of climate change in the greater Middle East, between approximately 4,500 and 3,000 years ago, reveals local evidence of resilience and even of a flourishing ancient society despite the changes in climate seen in the larger region.

View of Early Bronze Age excavation (Field 1) at Tell Tayinat in Hatay, Turkey
[Credit: Tayinat Archaeological Project]

A new study led by University of Toronto and Cornell University archaeologists working at Tell Tayinat in southeastern Turkey, demonstrates that human responses to climate change are variable and must be examined using extensive and precise data gathered at the local level. The study highlights how challenge and collapse in some areas were matched by resilience and opportunities elsewhere.

The findings published in PLOS ONE are welcome contributions to discussions about human responses to climate change that broaden an otherwise sparse chronological framework for the northern part of the region known historically as the Levant, which stretches the length of the eastern edge of the Mediterranean Sea.

"The study shows the end of the Early Bronze Age occupation at Tayinat was a long and drawn out affair that, while it appears to coincide with the onset of a megadrought 4,200 years ago, was actually the culmination of processes that began much earlier," says Tim Harrison, professor and chair of the Department of Near & Middle Eastern Civilizations in the Faculty of Arts & Science at the University of Toronto (U of T), and director of the Tayinat Archaeological Project. "The archaeological evidence does not point towards significant local effects of the climate episode, as there is no evidence of drought stress in crops. Instead, these changes were more likely the result of local political and spatial reconfiguration."

Microscope image of Iron Age oak twig from Tell Tayinat in Hatay, Turkey
[Credit: Brita Lorentzen]

The mid-to late Early Bronze Age (3000-2000 BCE) and the Late Bronze Age (1600-1200 BCE) in the ancient Middle East are pivotal periods of early inter-connectedness among settlements across the region, with the development of some of the earliest cities and state-level societies. But these systems were not always sustainable, and both periods ended in collapse of civilisations/settlements, the reasons for which are highly debated.

The absence of detailed timelines for societal activity throughout the region leaves a significant gap in understanding the associations between climate change and social responses. While the disintegration of political or economic systems are indeed components of a societal response, collapse is rarely total.

Using radiocarbon dating and analysis of archaeological samples recovered from Tell Tayinat, a location occupied following two particularly notable climate change episodes 4,200 and again 3,200 years ago, the Toronto-Cornell team established a robust chronological timeframe for Tayinat for these two pivotal periods in the history of the ancient Middle East.

Microscope image of Early Bronze Age ash wood sample from Tell Tayinat in Hatay, Turkey
[Credit: Brita Lorentzen]

"The absolute dating of these periods has been a subject of considerable debate for many years, and this study contributes a significant new dataset that helps address many of the questions," says Sturt Manning, Goldwin Smith Professor of Classical Archaeology in the Department of Classics at Cornell University's College of Arts & Sciences, and lead author of the study.

"The detailed chronological resolution achieved in this study allows for a more substantive interpretation of the archaeological evidence in terms of local and regional responses to proposed climate change, shedding light on how humans respond to environmental stress and variability."

The researchers say the chronological framework for the Early Iron Age demonstrates the thriving re-settlement of Tayinat following the 3,200 years ago event during a reconstructed period of heightened aridity.

"The settlement of Tayinat may have been undertaken to maximize access to arable land, and crop evidence reveals the continued cultivation of numerous water-demanding crops, revealing a response that counters the picture of a drought-stricken region," says Harrison. "The Iron Age at Tayinat represents a significant degree of societal resilience during a period of climatic stress."

Source: University of Toronto [October 29, 2020]

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The Mycenaean necropolis of Trapeza, Aegion, comes to light

A large number of grave offerings and high-quality burial items were discovered during the five-year excavation programme at the Mycenaean necropolis of Trapeza, seven kilometers southwest of Aegion. The findings testify to the region’s amazing cultural and social vitality. The plateau is identified with the city of Rhypes, the metropolis of Croton in Magna Graecia during the colonization of the 8th century BC.

View of chamber of Tomb 1 [Credit: MOCAS]

The Mycenaean necropolis is located on the southwestern slope of the plateau and on the ancient road leading to the citadel of historical times. The excavated tombs are arranged on at least three levels of terraces along the south side of Trapeza, a few meters from each other, in a parallel arrangement and with a north-south orientation. These are chamber tombs carved into the soft rock of the subsoil.

View of chamber of Tomb 7 [Credit: MOCAS]

The necropolis comprises tombs with chambers no wider than 3.5-4 meters and streets not exceeding a length of 6-7 meters and a width of 1.5 meters. The burial chambers have various shapes; circular, rectangular and even almost quadrangular with rounded corners and walls with irregular contours. Elongated pits were unearthed below the chambers, carved niches in the streets’ retaining walls for the secondary deposition of older burials, as well as elliptical or square pits dug in the street surfaces which were found to be empty and could have been originally been carved for concealing ritual ware. The side chambers in the streets of the tombs where children were buried are of particular importance.

View of Tomb 2 with the chamber’s entrance door [Credit: MOCAS]

The tombs were used repeatedly and over a long period of time. The tomb chambers collapsed in historical times, between the Geometric and Archaic period, as indicated by the artefacts found in “craters” formed in the ground owing to the collapse of the chambers’ roofs.

View of the archaeological site from the southwest [Credit: MOCAS]

The necropolis, founded in the LH IIIA 1 period, experienced its heyday during the Early Palatial period of the Mycenaean world, i.e. in parallel with the heights reached by the great centers of Mycenae, Tiryns and Pylos. A significant reuse of the tombs dates back to the 12th century BC, during the Post-Palatial period, probably after the early LH IIIC, when the tombs were repeatedly reopened, being at the same time a place of burial customs and complex ritual practices until the end of the Bronze Age, probably in the advanced Sub-Mycenaean period.

Assemblage of vessels from the Mycenean necropolis of Trapeza [Credit: MOCAS]

The quality of the finds of the Mycenaean necropolis of Trapeza is proved by the valuable sets of vessels that show a dependence on palace standards but also autonomous links with other regions, from the western Peloponnese to Crete. The grave goods are enriched with numerous seal stones and all kinds of beads and tesserae from various materials – glass, faience, gold, carnelian, rock crystal – that make up necklaces and ornate jewelry, ox head shaped gold-amulets indicating trading relations with the eastern Aegean and Cyprus.  A few tombs show elements of elitism, declaring social prestige and a possible connection with the palaces especially by a valuable combination of weapons and tools.

Assemblage of vessels from the chamber of Tomb 6 [Credit: MOCAS]

The Post-Palatial period from the 12th century BC.and after includes various phases of use, which impress mainly for their ritual practices. These relate to the treatment of the bones and remains of the former deceased, who are regarded as glorious ancestors and become the recipients of offerings. The purpose of these ceremonies is to create a genealogical bond by activating the memory of a past perceived as an integral part of the community.

Collected intact vessels from Tomb 2 [Credit: MOCAS]

Moreover, the findings from the backfills of the streets of tombs provide exclusive evidence of social practices that are a milestone in the conducting of a funeral, but also of rituals such as offerings and libations in front of the sealed chamber doors during posthumous visits to the tombs. Thus, the necropolis also becomes a place for transmitting traditions and a collective memory.

Bronze weapons from the chamber of Tomb 6 [Credit: MOCAS]

The location of the Mycenaean settlement of Trapeza is not yet clear. During the early cycle of use of the necropolis, the settlement was possibly situated on a hill, about 100 meters south of Trapeza. Today, research of a Middle Helladic settlement is in progress at this site, yielding sporadic evidence of Mycenaean pottery.

Bird shaped askos vessel [Credit: MOCAS]

The systematic excavation of Trapeza in Aigion, is headed by Dr. Andreas G. Bordos of the Ephorate of Antiquities of Achaia. Participating in the interdisciplinary research programme of the Mycenaean necropolis are Elisabetta Borgna, Professor of Aegean Archaeology at the University of Udine, with a group of students from the Universities of Udine, Trieste and Venice, as well as postgraduate students from Greek universities.

Source: Greek Ministry of Culture [trsl. Archaeology & Arts, October 29, 2020]

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Denisovan DNA in the genome of early East Asians

In 2006, miners discovered a hominin skullcap with peculiar morphological features in the Salkhit Valley of the Norovlin county in eastern Mongolia. It was initially referred to as Mongolanthropus and thought to be a Neandertal or even a Homo erectus. The remains of the "Salkhit" individual represent the only Pleistocene hominin fossil found in the country.

The skullcap found in the Salkhit Valley in eastern Mongolia belonged to a woman who lived 34,000
 years ago. Analyses showed: She had inherited about 25 percent of her DNA from Western
Eurasian [Credit: Institute of Archaeology, Mongolian Academy of Sciences]

Ancient DNA extracted from the skullcap shows that it belonged to a female modern human who lived 34,000 ago and was more related to Asians than to Europeans. Comparisons to the only other early East Asian individual genetically studied to date, a 40,000-year-old male from Tianyuan Cave outside Beijing (China), show that the two individuals are related to each other. However, they differ insofar that a quarter of the ancestry of the Salkhit individual derived from western Eurasians, probably via admixture with ancient Siberians.

Migration and interaction

"This is direct evidence that modern human communities in East Asia were already quite cosmopolitan earlier than 34,000 years ago", says Diyendo Massilani, lead author of the study and researcher at the Max-Planck Institute for Evolutionary Anthropology. "This rare specimen shows that migration and interactions among populations across Eurasia happened frequently already some 35,000 years ago".

Xiahe Mandible [Credit: Menghan Qiu, Dongju Zhang,
 Lanzhou University]

The researchers used a new method developed at the Max-Planck Institute for Evolutionary Anthropology to find segments of DNA from extinct hominins in the Salkhit and Tianyuan genomes. They found that the two genomes contain not only Neandertal DNA but also DNA from Denisovans, an elusive Asian relative of Neandertals. 

"It is fascinating to see that the ancestors of the oldest humans in East Asia from whom we have been able to obtain genetic data had already mixed with Denisovans, an extinct form of hominins that has contributed ancestry to present-day populations in Asia and Oceania", says Byambaa Gunchinsuren, a researcher at the Institute of Archaeology of the Mongolian Academy of Sciences. "This is direct evidence that Denisovans and modern humans had met and mixed more than 40,000 years ago".

"Interestingly, the Denisovan DNA fragments in these very old East Asians overlap with Denisovan DNA fragments in the genomes of present-day populations in East Asia but not with Denisovan DNA fragments in Oceanians. This supports a model of multiple independent mixture events between Denisovans and modern humans", says Massilani.

The research is reported in two papers in the journal Science [paper1, paper2].

Source: Max-Planck-Gesellschaft [October 29, 2020]

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Pterosaurs undergo dental examination to reveal clues about diets and lifestyles

Microscopic analysis of the teeth of pterosaurs has revealed new insights into the diets and behaviours of Earth's earliest flying reptiles.

Credit: University of Birmingham

Researchers at the University of Leicester's Centre for Palaeobiology Research and the University of Birmingham used dental microwear analysis to look at the wear patterns still visible on the teeth of 17 different species of pterosaur. They compared these with similar patterns on the teeth of modern reptiles, including monitor lizards and crocodilians, where much more is known about their diet.

The team was able to show for the first time how the technique can be used to not only tell us what these animals ate, but also to challenge ideas about their lifestyles and evolution. Their results are published in Nature Communications.

"Most existing ideas about what pterosaurs ate come from comparisons of the shapes of their teeth with those of living animals," explains lead author Dr. Jordan Bestwick, of the University of Birmingham's School of Geography, Earth and Environmental Sciences. "For example, if the animal had conical teeth like a crocodile, we might assume it ate fish. But this approach has obvious shortcomings—the teeth of pandas and polar bears, for example, are similar, but comparing them wouldn't give us an accurate picture of their diets."

The analysis showed that modern reptiles with rougher wear on their tooth surfaces are more likely to have eaten crunchy things, such as shelled invertebrates—beetles or crabs—whereas reptiles which eat mainly soft items, such as fish, have smoother tooth surfaces. By applying the technique to pterosaurs the team was able to determine the diet of each species.

Dr. Bestwick says: "Our analysis has yielded some fascinating insights into individual species, but also into some of the bigger questions around how these pterosaurs evolved and whether their lifestyles were more similar to those of modern day birds or reptiles. Evidence from dental microwear analysis can shed new light on this debate."

Professor Mark Purnell, Professor of Palaeobiology at the University of Leicester said: "This is the first time this technique has been applied in this way to ancient reptiles, and it's great to find it works so well. Often, palaeontologists have very little to go on when trying to understand what extinct animals ate. This approach gives us a new tool, allowing us to move from what are sometimes little more than educated guesses, into the realms of solid science."

 

In one example, the team examined the teeth of Rhamphorhynchus, a long-tailed pterosaur from the Jurassic period. Researchers found that juvenile Rhamphorhynchus had insect-based diets, whereas their adult counterparts—about the size of a large seagull—were more likely to have eaten fish. This suggests a species in which the adults took little care of their young—a behaviour that is common in reptiles and is not exhibited by birds.

The team also investigated whether their analysis could shed light on how different species of pterosaurs evolved. Pterosaurs lived between 210 and 66 million years ago, eventually dying out at the same time as dinosaurs. In that time, according to the dental microwear analysis, there was a general shift in diet from invertebrates such as insects, towards a more meat or fish-based diet.

"We found that the earliest forms of pterosaurs ate mainly crunchy invertebrates," says Dr. Bestwick. "The shift towards eating fish or meat coincides with the evolution of birds. We think it's possible, therefore, that competition with birds could explain the decline of smaller-bodied pterosaurs and a rise in larger, carnivorous species."

Natalia Jagielska, a Ph.D. researcher in pterosaur palaeontology at the University of Edinburgh, (not involved in this study) says the research adds much-needed clarity to the behaviour and ecological role of pterosaurs in ancient food webs.

"Pterosaurs are a fascinating group of Mesozoic reptiles with astounding diversity in tooth morphology," she says. "This study is important for contributing to the idea that young Rhamphorhynchus were independent invertebrate hunters before becoming fish consumers, rather than being fed and nurtured by parents, like birds. Or that in pterosaur-rich environments, like the Late Jurassic Bavarian lagoons, pterosaur species have partitioned to occupy variations of dietary niches."

The research team anticipate their methods will set a new benchmark for robust interpretation of extinct reptile diets, paving the way for an enhanced understanding of ancient ecosystems.

Source: University of Birmingham [October 29, 2020]

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Study of ancient dog DNA traces canine diversity to the Ice Age

A global study of ancient dog DNA, led by scientists at the Francis Crick Institute, University of Oxford, University of Vienna and archaeologists from more than 10 countries, presents evidence that there were different types of dogs more than 11,000 years ago in the period immediately following the Ice Age.

Veretye dog image [Credit: E.E. Antipina]

In their study, published in Science, the research team sequenced ancient DNA from 27 dogs, some of which lived up to nearly 11,000 years ago, across Europe, the Near East and Siberia. They found that by this point in history, just after the Ice Age and before any other animal had been domesticated, there were already at least five different types of dog with distinct genetic ancestries.

This finding reveals that the diversity observed between dogs in different parts of the world today originated when all humans were still hunters and gatherers.

Pontus Skoglund, author and group leader of the Crick's Ancient Genomics laboratory, says: "Some of the variation you see between dogs walking down the street today originated in the Ice Age. By the end of this period, dogs were already widespread across the northern hemisphere."

This study of ancient genomics involves extracting and analysing DNA from skeletal material. It provides a window into the past, allowing researchers to uncover evolutionary changes that occurred many thousands of years ago.

The team showed that over the last 10,000 years, these early dog lineages mixed and moved to give rise to the dogs we know today. For example, early European dogs were initially diverse, appearing to originate from two highly distinct populations, one related to Near Eastern dogs and another to Siberian dogs. However, at some point this diversity was lost, as it is not present in European dogs today.

Anders Bergström, lead author and post-doctoral researcher in the Ancient Genomics laboratory at the Crick, says: "If we look back more than four or five thousand years ago, we can see that Europe was a very diverse place when it came to dogs. Although the European dogs we see today come in such an extraordinary array of shapes and forms, genetically they derive from only a very narrow subset of the diversity that used to exist."

The researchers also compared the evolution in dog history to changes in human evolution, lifestyles and migrations. In many cases comparable changes took place, likely reflecting how humans would bring their dogs with them as they migrated across the world.

But there are also cases when human and dog histories do not mirror each other. For example, the loss of diversity that existed in dogs in early Europe was caused by the spread of a single dog ancestry that replaced other populations. This dramatic event is not mirrored in human populations, and it remains to be determined what caused this turnover in European dog ancestry. 

Greger Larson, author and Director of the Palaeogenomics and Bio-Archaeology Research Network at the University of Oxford, says: "Dogs are our oldest and closest animal partner. Using DNA from ancient dogs is showing us just how far back our shared history goes and will ultimately help us understand when and where this deep relationship began."

Ron Pinhasi, author and group leader at the University of Vienna, says: "Just as ancient DNA has revolutionised the study of our own ancestors, it's now starting to do the same for dogs and other domesticated animals. Studying our animal companions adds another layer to our understanding of human history."

While this study provides major new insights into the early history of dog populations and their relationships with humans and each other, many questions still remain. In particular, research teams are still trying to uncover where and in which human cultural context, dogs were first domesticated.

Source: The Francis Crick Institute [October 29, 2020]

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