About 2 million years ago, Homo Erectus lived at high altitudes and produced both Oldowan and Acheulean tools

 

Two million years ago, Homo erectus had expanded beyond the lowland savanna environments of East Africa and into the high-altitude regions of the Ethiopian highlands, where they produced both Oldowan and Acheulean tools, according to a new study. It presents a reanalysis of an early hominin fossil first discovered in 1981. The findings provide novel insights into the evolution, migration and adaptive capacities of early human ancestors. In Africa, the limited number of hominin fossils found in direct association with stone tools has hindered attempts to link Homo habilis and Homo erectus with particular stone tool industries, namely Oldowan or Acheulean. 

One region critical to studying this question is a collection of sites known as the Melka Kunture complex – a cluster of prehistoric sites on the highlands of Ethiopia at an altitude of ~2000 meters above sea level. In 1981, a fossilized infant mandible was discovered at the Garba IV site and in direct association with Oldowan lithic tools. However, the hominin species the fossil represents has been the subject of debate. 

In this study, Margherita Mussi and colleagues evaluate the geochronological context of the Garba IV site and re-assess the taxonomic affinity of the fossil mandible. Using synchrotron imaging to examine the internal morphology of the unerupted teeth in the Garba IV mandible, Mussi et al. confirm that it belonged to H. erectus. Moreover, combining preliminary argon-argon dates for the site’s stratigraphy with a more recently published magnetostratigraphic analysis, the authors argue that the fossil is around 2 million years old, making it one of the earliest H. erectus specimens yet discovered and the only one in clear association with an abundant Oldowan lithic industry. The overlying Acheulean tool-bearing strata, which date to ~1.95 million years ago, represent the earliest known evidence of Acheulean lithic technology. According to Mussi et al., the findings demonstrate that by 2 million years ago, H. erectus adapted early and quickly to a high-altitude mountain environment, first producing Oldowan technology and then Acheulean technology.

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JOURNAL

Science

DOI

10.1126/science.add9115 

Pre- Columbian cultures of the Caribbean consumed a diversity of plants, with peanuts, papaya, maize, and even cotton and tobacco

 

 

IMAGE: 

COPROLITES AND ARTIFACTS RECOVERED FROM THE HUECOID AND SALADOID ARCHAEOLOGICAL SITES.

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CREDIT: CHANLATTE AND NARGANES, CC-BY 4.0 (HTTPS://CREATIVECOMMONS.ORG/LICENSES/BY/4.0/)

DNA analysis of mummified poop reveals two pre-Columbian Caribbean cultures ate a wide variety of plants, like maize, sweet potato, and peanuts—and tobacco and cotton traces were detected too, according to a study published October 11, 2023 in the open-access journal PLOS ONE by Jelissa Reynoso-García from the University of Puerto Rico, Puerto Rico, and colleagues.

Mummified poop, or coprolites, can reveal clues to diet and lifestyle. In this study, Reynoso-García and colleagues analyzed plant DNA isolated from coprolites sampled from archeological sites of two pre-Columbian cultures (Huecoid and Saladoid) to see what these peoples ate and drank.

The authors carefully extracted and analyzed plant DNA from ten coprolite samples at the La Hueca archaeological site in Puerto Rico. They compared the extracted plant DNA against a database of diverse coprolite samples and contemporary plant DNA sequences.

The results suggest that Huecoid and Saladoid people enjoyed a diverse and sophisticated food system, with sweet potato, wild and domesticated peanut, chili peppers, a domesticated strain of tomatoes, papaya and maize all detected. The analysis also detected tobacco, possibly due to the use of chewing tobacco, pulverized tobacco inhalation, or tobacco as a food additive for medicinal and/or hallucinogenic purposes. Also surprisingly, cotton was detected—perhaps due to the use of ground cotton seeds for oil, or because women wet the cotton strands with their saliva leaving strands in the mouth while weaving. The authors did not find evidence of cassava/manioc/yucca (Manihot esculenta) consumption, though this plant was often reported as a staple food in the pre-Columbian Caribbean by chroniclers. The authors note that the elaborate grating and drying cassava preparation techniques reported in these accounts might have degraded the plant DNA, or that this might have been a seasonal staple food.

Due to food preparation techniques, the fact that each coprolite sample is only a snapshot of what one specific person had been recently eating, and the limitation that the authors were only able to identify plants also in current DNA sequence databases (not capturing any now-extinct, rare, or non-commercial crops) it’s likely that the Huecoid and Saladoid people ate other plants or fungi not noted here. Nevertheless, the authors hope this analysis gives further insight into the lives of pre-Columbian people of the Americas.

Dr. Toranzos adds: "Who would have thought that something that we avoid even looking at would contain so much information? It’s especially incredible that this is so even after thousands of years."

The freely available article in PLOS ONE: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0292077

Neanderthal gene variants associated with greater pain sensitivity

 

People who carry three gene variants that have bene inherited from Neanderthals are more sensitive to some types of pain, according to a new study co-led by UCL researchers.

The findings, published in Communications Biology, are the latest findings to show how past interbreeding with Neanderthals has influenced the genetics of modern humans.

The researchers found that people carrying three so-called Neanderthal variants in the gene SCN9A, which is implicated in sensory neurons, are more sensitive to pain from skin pricking after prior exposure to mustard oil.

Previous research has identified three variations in the SCN9A gene — known as M932L, V991L, and D1908G — in sequenced Neanderthal genomes and reports of greater pain sensitivity among humans carrying all three variants. However, prior to this study the specific sensory responses affected by these variants was unclear.

An international team led by researchers at UCL, Aix-Marseille University, University of Toulouse, Open University, Fudan University, and Oxford University, and part-funded by Wellcome, measured the pain thresholds of 1,963 people from Colombia in response to a range of stimuli.

The SCN9A gene encodes a sodium channel that is expressed at high levels in sensory neurons that detect signals from damaged tissue. The researchers found that the D1908G variant of the gene was present in around 20% of chromosomes within this population and around 30% of chromosomes carrying this variant also carried the M932L and V991L variants.

The authors found that the three variants were associated with a lower pain threshold in response to skin pricking after prior exposure to mustard oil, but not in response to heat or pressure. Additionally, carrying all three variants was associated with greater pain sensitivity than carrying only one.

When they analysed the genomic region including SCN9A using genetic data from 5,971 people from Brazil, Chile, Colombia, Mexico and Peru, the authors found that the three Neanderthal variants were more common in populations with higher proportions of Native American ancestry, such as the Peruvian population, in which the average proportion of Native American ancestry was 66%.

The authors propose that the Neanderthal variants may sensitise sensory neurons by altering the threshold at which a nerve impulse is generated. They speculate that the variants may be more common in populations with higher proportions of Native American ancestry as a result of random chance and population bottlenecks that occurred during the initial occupation of the Americas. Although acute pain can moderate behaviour and prevent further injury, the scientists that say additional research is needed to determine whether carrying these variants and having greater pain sensitivity may have been advantageous during human evolution.

Previous research by co-corresponding author Dr Kaustubh Adhikari (UCL Genetics, Evolution & Environment and The Open University) has shown that humans also inherited some genetic material from Neanderthals affecting the shape of our noses.*

Dr Adhikari commented: “In the last 15 years, since the Neanderthal genome was first sequenced, we have been learning more and more about what we have inherited from them as a result of interbreeding tens of thousands of years ago.

“Pain sensitivity is an important survival trait that enables us to avoid painful things that could cause us serious harm. Our findings suggest that Neanderthals may have been more sensitive to certain types of pain, but further research is needed for us to understand why that is the case, and whether these specific genetic variants were evolutionarily advantageous.”

First author Dr Pierre Faux (Aix-Marseille University and University of Toulouse) said: “We have shown how variation in our genetic code can alter how we perceive pain, including genes that modern humans acquired from the Neanderthals. But genes are just one of many factors, including environment, past experience, and psychological factors, which influence pain.”

 

* UCL News, 2023: Nose shape gene inherited from Neanderthals

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JOURNAL

Communications Biology

DOI

10.1038/s42003-023-05286-z 

Ancient Maya reservoirs offer lessons for today’s water crises

 

Peer-Reviewed Publication

UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN, NEWS BUREAU

 

IMAGE: 

THE MAYA BUILT AND MAINTAINED SELF-CLEANING WETLAND RESERVOIRS THAT SERVED URBAN POPULATIONS OVER MILLENNIA. U. OF I. ANTHROPOLOGY PROFESSOR LISA LUCERO WRITES THAT THE WATER-RELATED CRISES THEY FACED HOLD LESSONS FOR TODAY.

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CREDIT: PHOTO BY FRED ZWICKY

CHAMPAIGN, Ill. — According to a new paper, ancient Maya reservoirs, which used aquatic plants to filter and clean the water, “can serve as archetypes for natural, sustainable water systems to address future water needs.”

The Maya built and maintained reservoirs that were in use for more than 1,000 years, wrote University of Illinois Urbana-Champaign anthropology professor Lisa Lucero in a perspective in the Proceedings of the National Academy of Sciences. These reservoirs provided potable water for thousands to tens of thousands of people in cities during the annual, five-month dry season and in periods of prolonged drought.

“Most major southern lowland Maya cities emerged in areas that lacked surface water but had great agricultural soils,” Lucero said. “They compensated by constructing reservoir systems that started small and grew in size and complexity.”

Over time, the Maya built canals, dams, sluices and berms to direct, store and transport water. They used quartz sand for water filtration, sometimes importing it from great distances to massive cities like Tikal in what is now northern Guatemala. A sediment core from one of Tikal’s reservoirs also found that zeolite sand had been used in its construction. Previous studies have shown that this volcanic sand can filter impurities and disease-causing microbes from water. The zeolite also would have been imported from sources about 18 miles (30 kilometers) away.

“Tikal’s reservoirs could hold more than 900,000 cubic meters of water,” Lucero wrote. Estimates suggest that up to 80,000 people lived in the city and its environs in the Late Classic period, roughly 600 to 800 C.E. The reservoirs kept people and crops hydrated during the dry season, Lucero said.

Maya royalty got much of their status from their ability to provide water to the populace.

“Clean water and political power were inextricably linked – as demonstrated by the fact that the largest reservoirs were built near palaces and temples,” Lucero wrote. The kings also performed ceremonies to gain the favor of ancestors and the rain god, Chahk.

A key challenge was to keep standing water in reservoirs from becoming stagnant and undrinkable, and for that the Maya likely relied on aquatic plants, many of which still populate Central American wetlands today, Lucero said. These include cattails, sedges, reeds and others. Some of these plants have been identified in sediment cores from Maya reservoirs.

These plants filtered the water, reducing murkiness and absorbing nitrogen and phosphorous, Lucero said.

“The Maya would have had to dredge every several years… (and) harvest and replenish aquatic plants,” she wrote. The nutrient-laden soils and plants removed from reservoirs could then be used to fertilize urban fields and gardens.

The most iconic aquatic plant associated with the ancient Maya is the water lily, Nymphaea ampla, which thrives only in clean water, Lucero said. Its pollen has been found in sediment cores from several Maya reservoirs. Water lilies symbolized “Classic Maya kingship,” Lucero wrote.

“The kings even donned headdresses adorned with the flowers and are depicted with water lilies in Maya art,” Lucero said.

“Water lilies do not tolerate acidic conditions or too much calcium such as limestone or high concentrations of certain minerals like iron and manganese,” she wrote.

To keep water lilies alive, water managers would have had to line the reservoirs with clay, Lucero said. A layer of sediment would be needed for plants’ roots. In turn, the water lilies and trees and shrubs planted near the reservoirs shaded the water, cooling it and inhibiting the growth of algae.

“The Maya generally did not build residences near reservoir edges, so contamination seeping through the karstic terrain would not have been an issue,” Lucero wrote.

The evidence gathered from several southern lowland cities indicates that, as constructed wetlands, Maya reservoirs supplied potable water to people for more than 1,000 years, failing only when the severest droughts took hold in the region between 800 and 900 C.E., Lucero said. She notes that current climate trends will require many of the same approaches the Maya employed, including the use of aquatic plants to improve and maintain water quality naturally.

“Constructed wetlands provide many advantages over conventional wastewater treatment systems,” she wrote. “They provide an economical, low technology, less expensive and high energy-saving treatment technology.”

In addition to providing clean water, constructed wetlands also support aquatic animals and can be a source of nutrients to replenish agricultural soils, she wrote.

            “The next step moving forward is to combine our respective expertise and implement the lessons embodied in ancient Maya reservoirs in conjunction with what is currently known about constructed wetlands,” she wrote.

A 1900-year-old child’s nightgown, discovered in a cave in the Judean Desert

Over the years, thousands of scraps of textiles dating from the Roman period have been found at different sites in Israel, but textiles with intriguing “knots” have only been uncovered in the Cave of the Letters in the Judean Desert. “The knots are like small pendants at the bottom of the garment, created by tying part of the fabric around substances known for their protective qualities: resin, salt, iron sulfate, asphalt, henna, seeds, and other unidentified materials. The binding was done by winding a flax thread around the material several times,” says Dr. Orit Shamir, Israel Antiquities Authority textile specialist.

Based on its size, the gown belonged to a child, and it has knots at its hem. It probably served as an undergarment worn beneath a decorative upper garment made of colorful wool. The gown is made up of two equal-sized panels sewn together along their upper edges, with an opening in the middle for the neck.

The gown is adorned with flax threads hanging down from both sides of the neck. “If we examine the fabric from which the tunic was made,” says Dr. Shamir, “We'll find that the thickness and density of the threads are not uniform. The weaving was simple, manufactured according to a simple twining technique, and occasionally mistakes were made. The sewing up of the garment is also not meticulous, and the garment has several holes, some of which resulted from wear and tear.”

Since there is no doubt that the nightgown is meant for a child, it may be speculated that the knots were hung on it to protect the child from illness and harm. “You can really imagine a mother hiding salt for protection and tying up a piece of the flax garment while reciting prayers and hopes for her son or daughter,” says Dr. Shamir.

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More than 10,000 pre-Columbian earthworks remain hidden throughout Amazonian forests

 

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

More than 10,000 Pre-Columbian archaeological sites likely rest undiscovered throughout the Amazon basin, estimates a new study. The findings, derived from remote sensing data and predictive spatial modeling, address questions about the influence of pre-Columbian societies on the Amazon region. “The massive extent of archaeological sites and widespread human-modified forests across Amazonia is critically important for establishing an accurate understanding of interactions between human societies, Amazonian forests, and Earth’s climate,” write the authors. Indigenous societies have called the Amazon basin home for more than 12,000 years, creating ancient earthwork structures and domesticated landscapes that have had long-lasting effects on modern forest composition. However, the size and scale of Amazon settlement and landscape transformation are poorly understood – sites are remote and often obscured by dense vegetation. As such, there has never been a comprehensive survey of pre-Columbian sites across the Amazon basin. 

Airborne LIDAR (light detection and ranging), a remote sensing technique that can map small changes in topography on the ground surface beneath the forest canopy, has been used to discover many previously unknown pre-Columbian structures and earthworks in heavily forested sites throughout Central and South America. Here, Vinicius Peripato and colleagues searched 5,315 square kilometers of LIDAR survey data and discovered 24 unreported human-made earthworks, including fortified villages, defensive and ceremonial structures, mountaintop settlements, and other geoglyphs, in regions across the Amazon basin. However, the LIDAR survey data covered only 0.08% of the total area of Amazonia. 

To better understand where and how many undocumented pre-Columbian sites might occur, Peripato et al. combined the data from their small basin-wide survey, as well as data on other previously identified sites with a predictive spatial distribution model. According to the model, between 10,272 and 23,648 large-scale pre-Columbian structures remain to be discovered, particularly in southwestern Amazonia. What’s more, the authors identified relationships between the predicted probability of earthworks and the occurrence and abundance of domesticated tree species and found significant association between the two, suggesting that active pre-Columbian Indigenous forest management practices have long shaped the ecology of modern forests across Amazonia. “Amazonian forests clearly merit protection not only for their ecological and environmental value but also for their high archaeological, social, and biocultural value, which can teach modern society how to sustainably manage its natural resources,” write Peripato et al.

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Study confirms age of oldest fossil human footprints in North America

Two new lines of evidence support the 21,000 to 23,000-year age estimate of the footprints first described and dated in 2021

The 2021 results began a global conversation that sparked public imagination and incited dissenting commentary throughout the scientific community as to the accuracy of the ages. 

  

“The immediate reaction in some circles of the archeological community was that the accuracy of our dating was insufficient to make the extraordinary claim that humans were present in North America during the Last Glacial Maximum. But our targeted methodology in this current research really paid off,” said Jeff Pigati, USGS research geologist and co-lead author of a newly published study that confirms the age of the White Sands footprints. 

  

The controversy centered on the accuracy of the original ages, which were obtained by radiocarbon dating. The age of the White Sands footprints was initially determined by dating seeds of the common aquatic plant  Ruppia cirrhosa that were found in the fossilized impressions. But aquatic plants can acquire carbon from dissolved carbon atoms in the water rather than ambient air, which can potentially cause the measured ages to be too old. 

  

“Even as the original work was being published, we were forging ahead to test our results with multiple lines of evidence,” said Kathleen Springer, USGS research geologist and co-lead author on the current Science paper. “We were confident in our original ages, as well as the strong geologic, hydrologic, and stratigraphic evidence, but we knew that independent chronologic control was critical.” 

  

For their follow-up study, the researchers focused on radiocarbon dating of conifer pollen, because it comes from terrestrial plants and therefore avoids potential issues that arise when dating aquatic plants like Ruppia. The researchers used painstaking procedures to isolate approximately 75,000 pollen grains for each sample they dated. Importantly, the pollen samples were collected from the exact same layers as the original seeds, so a direct comparison could be made. In each case, the pollen age was statistically identical to the corresponding seed age. 

 

“Pollen samples also helped us understand the broader environmental context at the time the footprints were made,” said David Wahl, USGS research geographer and a co-author on the current Science article. “The pollen in the samples came from plants typically found in cold and wet glacial conditions, in stark contrast with pollen from the modern playa which reflects the desert vegetation found there today.” 

  

In addition to the pollen samples, the team used a different type of dating called optically stimulated luminescence, which dates the last time quartz grains were exposed to sunlight. Using this method, they found that quartz samples collected within the footprint-bearing layers had a minimum age of ~21,500 years, providing further support to the radiocarbon results. 

 

With three separate lines of evidence pointing to the same approximate age, it is highly unlikely that they are all incorrect or biased and, taken together, provide strong support for the 21,000 to 23,000-year age range for the footprints. 

New radiocarbon (14C) and optically simulated luminescence ages have confirmed the controversial antiquity of the ancient human footprints discovered in White Sands National Park, and reported in a study in 2021. Addressing the widespread criticism of their previous study, researchers report that the independent ages from multiple resolved sources conclusively show that the footprints were left behind between roughly 23,000 and 20,000 years ago, demonstrating that humans were present in southern North America during the Last Glacial Maximum (LGM).

When and how humans first migrated into North America has long been debated and remains poorly understood. Current estimates for the timing of these first occupants range from ~13,000 years ago to more than 20,000 years ago. However, the earliest archaeological evidence for the region’s settlement is sparse and often controversial. In a Science study published in September 2021 (Bennett et al.), researchers reported the discovery of in situ human footprints preserved in an ancient lakebed dating to between ~23,000 and 21,000 years ago in what is now White Sands National Park – findings which suggest nearly 2,000 years of human occupation in North America during the height of the LGM. However, since the study’s publication, the accuracy of the radiocarbon dates has been debated. It’s argued that the ancient seeds from the aquatic plant (Ruppia cirrhosa) that were used to date the surfaces the footprints were embedded in have the potential to be affected by old carbon reservoir effects that could influence the reported radiocarbon ages and make them appear older than they truly are.

Here, Jeffery Pigati, Kathleen Springer, and colleagues report new evidence in the form of multiple independent age estimates of the White Sands footprints, which support their previous study’s claims. “We always knew that we would have to independently evaluate the accuracy of our ages to convince the archaeological community that the peopling of the Americas occurred far earlier than traditionally thought,” said Pigati.

In their new work, Pigati and Springer et al. present calibrated 14C ages of terrestrial pollen collected from the same stratigraphic contexts as the Ruppia seeds. Unlike the seeds, conifer pollen fixes atmospheric carbon and, therefore is not subject to potential old carbon reservoir effects. According to the findings, the resulting calibrated 14C ages range from 23.4 ± 2.5 – 22.6 ± 2.3 thousand years ago. In addition, the authors obtained optically simulated luminescence ages of the sediments from within the footprint-bearing strata, which produced a minimum age of 21.5 ± 1.9 thousand years ago. In both cases, Pigati and Springer et al. show that the resolved dates were statistically indistinguishable from the original calibrated 14C ages of the oldest Ruppia seeds reported previously. In a related Perspective, Bente Phillipson discusses the study and its findings in greater detail.  

“Even as the original work was being published, we were forging ahead to test our results with multiple lines of evidence and independent chronologic techniques,” said Kathleen Springer, co-lead author of the study. “Although we were confident in the original seed ages, we wanted to develop community confidence in them as well. Our new ages, combined with the strong geologic, hydrologic, and stratigraphic evidence, unequivocally support the conclusion that humans were present in North America during the last Glacial Maximum.”