Tuesday, March 31, 2020

Regular climbing behavior in a human ancestor U

A new study led by the University of Kent has found evidence that human ancestors as recent as two million years ago may have regularly climbed trees.
Walking on two legs has long been a defining feature to differentiate modern humans, as well as extinct species on our lineage (aka hominins), from our closest living ape relatives: chimpanzees, gorillas and orangutans. This new research, based on analysis of fossil leg bones, provides evidence that a hominin species (believed to be either Paranthropus robustus or early Homo) regularly adopted highly flexed hip joints; a posture that in other non-human apes is associated with climbing trees.
These findings came from analysing and comparing the internal bone structures of two fossil leg bones from South Africa, discovered over 60 years ago and believed to have lived between 1 and 3 million years ago. For both fossils, the external shape of the bones were very similar showing a more human-like than ape-like hip joint, suggesting they were both walking on two legs. The researchers examined the internal bone structure because it remodels during life based on how individuals use their limbs. Unexpectedly, when the team analysed the inside of the spherical head of the femur, it showed that they were loading their hip joints in different ways.
The research project was led by Dr Leoni Georgiou, Dr Matthew Skinner and Professor Tracy Kivell at the University of Kent's School of Anthropology and Conservation, and included a large international team of biomechanical engineers and palaeontologists. These results demonstrate that novel information about human evolution can be hidden within fossil bones that can alter our understanding of when, where and how we became the humans we are today.
Dr Georgiou said: 'It is very exciting to be able to reconstruct the actual behaviour of these individuals who lived millions of years ago and every time we CT scan a new fossil it is a chance to learn something new about our evolutionary history.'
Dr Skinner said: 'It has been challenging to resolve debates regarding the degree to which climbing remained an important behaviour in our past. Evidence has been sparse, controversial and not widely accepted, and as we have shown in this study the external shape of bones can be misleading. Further analysis of the internal structure of other bones of the skeleton may reveal exciting findings about the evolution of other key human behaviours such as stone tool making and tool use. Our research team is now expanding our work to look at hands, feet, knees, shoulders and the spine.'

Well-engineered 'watercourts' stored live fish, fueling Florida's Calusa kingdom

GAINESVILLE, Fla. --- The mighty Calusa ruled South Florida for centuries, wielding military power, trading and collecting tribute along routes that sprawled hundreds of miles, creating shell islands, erecting enormous buildings and dredging canals wider than some highways. Unlike the Aztecs, Maya and Inca, who built their empires with the help of agriculture, the Calusa kingdom was founded on fishing.
But like other expansive cultures, the Calusa would have needed a surplus of food to underwrite their large-scale construction projects. This presented an archaeological puzzle: How could this coastal kingdom keep fish from spoiling in the subtropics?
new study points to massive structures known as watercourts as the answer. Built on a foundation of oyster shells, these roughly rectangular enclosures walled off portions of estuary and likely served as short-term holding pens for fish before they were eaten, smoked or dried. The largest of these structures is about 36,000 square feet - more than seven times bigger than an NBA basketball court - with a berm of shell and sediment about 3 feet high. Engineering the courts required an intimate understanding of daily and seasonal tides, hydrology and the biology of various species of fish, researchers said.
The watercourts help explain how the Calusa could rely primarily on the sea.
"What makes the Calusa different is that most other societies that achieve this level of complexity and power are principally farming cultures," said William Marquardt, curator emeritus of South Florida Archaeology and Ethnography at the Florida Museum of Natural History. "For a long time, societies that relied on fishing, hunting and gathering were assumed to be less advanced. But our work over the past 35 years has shown the Calusa developed a politically complex society with sophisticated architecture, religion, a military, specialists, long-distance trade and social ranking - all without being farmers."
The fact that the Calusa were fishers, not farmers, created tension between them and the Spaniards, who arrived in Florida during the 16th century when the Calusa kingdom was at its zenith, said study lead author Victor Thompson, director of the University of Georgia's Laboratory of Archaeology.
"The Spanish soldiers, priests and officers were used to dealing with agriculturalists, such as the people they colonized in the Caribbean who grew maize surpluses for them," Thompson said. "This would not have been possible with the Calusa. In fact, in a late 1600s mission attempt by the Franciscans, hoes were unloaded off the ship, and when the Calusa saw this, they remarked, 'Why didn't they also bring slaves to till the ground?'"
Thompson, Marquardt and colleagues analyzed two watercourts along the southwest shore of Mound Key, an island in Estero Bay off Florida's Gulf Coast and the seat of Calusa power for about 500 years.
These courts, still visible today, flank the grand canal, a marine highway nearly 2,000 feet long and averaging 100 feet wide, which bisects the key. Both have yards-long openings in the berms along the canal, possibly to allow Calusa to drive fish into the enclosures, which could then be closed with a gate or net.
The team studied the watercourts and surrounding areas using remote sensors, cores of sediment and shell and excavations. The bisected key features two large shell mounds, one on either side of the island. Remote sensing showed slopes leading from the watercourts to the top of the mounds, which may have been causeways for transporting food. On the shoreline, researchers found evidence of burning and small post molds, possibly for racks used to smoke and dry fish.
Radiocarbon dating suggests the watercourts were built between A.D. 1300 and 1400 - around the end of a second phase in the construction of a king's manor, an impressive structure that would eventually hold 2,000 people, according to Spanish documents.
A.D. 1250 also corresponds to a drop in sea level, which "may have impacted fish populations enough to help inspire some engineering innovation," said Karen Walker, Florida Museum collection manager of South Florida Archaeology and Ethnography.
Fish bones and scales found in the western watercourt show the Calusa were capturing mullet and likely pinfish and herring, all schooling species. Florida Gulf Coast University geologist Michael Savarese's analysis of watercourt core samples revealed dark gray sediment that was rich in organic material, suggesting poor circulation. High tide would have refreshed the water to some extent, Marquardt said.
"We can't know exactly how the courts worked, but our gut feeling is that storage would have been short-term - on the order of hours to a few days, not for months at a time," he said.
While researchers previously hypothesized watercourts were designed to hold fish, this is the first attempt to study the structures systematically, including when they were built and how that timing correlates with other Calusa construction projects, Marquardt said.
The Calusa dramatically shaped their natural environment, but the reverse was also true, Thompson said.
"The fact that the Calusa obtained much of their food from the estuaries structured almost every aspect of their lives," he said. "Even today, people who live along coasts are a little different, and their lives continue to be influenced by the water - be it in the food they eat or the storms that roll in on summer afternoons in Southwest Florida."

Mesoamerican copper smelting technology aided colonial weaponry

When Spanish invaders arrived in the Americas, they were generally able to subjugate the local peoples thanks, in part, to their superior weaponry and technology. But archeological evidence indicates that, in at least one crucial respect, the Spaniards were quite dependent on an older indigenous technology in parts of Mesoamerica (today's Mexico, Guatemala, Belize, and Honduras).
The invaders needed copper for their artillery, as well as for coins, kettles, and pans, but they lacked the knowledge and skills to produce the metal. Even Spain at that time had not produced the metal domestically for centuries, relying on imports from central Europe. In Mesoamerica they had to depend on local smelters, furnace builders, and miners to produce the essential material. Those skilled workers, in turn, were able to bargain for exemption from the taxes levied on the other indigenous people.
This dependence continued for at least a century, and perhaps as long as two centuries or more, according to new findings published in the journal Latin American Antiquity, in a paper by Dorothy Hosler, professor of archeology and ancient technology at MIT, and Johan Garcia Zaidua, a researcher at the University of Porto, in Portugal.
The research, at the site of El Manchón, in Mexico, made use of information gleaned from more than four centuries worth of archeological features and artifacts excavated by Hosler and her crew over multiple years of fieldwork, as well as from lab work and historical archives in Portugal, Spain, and Mexico analyzed by Garcia.
El Manchón, a large and remote settlement, initially displayed no evidence of Spanish presence. The site consisted of three steep sectors, two of which displayed long house foundations, some with interior rooms and religious sanctuaries, patios, and a configuration that was conceptually Mesoamerican but unrelated to any known ethnic groups such as the Aztec. In between the two was an area that contained mounds of slag (the nonmetallic material that separates out during smelting from the pure metal, which floats to the surface).
The Spanish invaders urgently needed enormous quantities of copper and tin to make the bronze for their cannons and other armaments, Hosler says, and this is documented in the historical and archival records. But "they didn't know how to smelt," she says, whereas archaeological data suggest the indigenous people had already been smelting copper at this settlement for several hundred years, mostly to make ritual or ceremonial materials such as bells and amulets. These artisans were highly skilled, and in Guerrero and elsewhere had been producing complex alloys including copper-silver, copper-arsenic, and copper-tin for hundreds of years, working on a small scale using blowpipes and crucibles to smelt the copper and other ores.
But the Spanish desperately required large quantities of copper and tin, and in consultation with indigenous smelters introduced some European technology into the process. Hosler and her colleagues excavated an enigmatic feature that consisted of two parallel courses of stones leading toward a large cake of slag in the smelting area. They identified this as the remains of a thus-far-undocumented hybrid type of closed furnace design, powered by a modified hand-held European bellows. A small regional museum in highland Guerrero illustrates just such a hybrid furnace design, including the modified European-introduced bellows system, capable of producing large volumes of copper. But no actual remains of such furnaces had previously been found.
The period when this site was occupied spanned from about 1240 to 1680, Hosler says, and may have extended to both earlier and later times.
The Guerrero site, which Hosler excavated over four field seasons before work had to be suspended because of local drug cartel activity, contains large heaps of copper slag, built up over centuries of intensive use. But it took a combination of the physical evidence, analysis of the ore and slags, the archaeological feature in the the smelting area, the archival work, and reconstruction drawing to enable identification of the centuries of interdependence of the two populations in this remote outpost.
Earlier studies of the composition of the slag at the site, by Hosler and some of her students, revealed that it had formed at a temperature of 1150 degrees Celsius, which could not have been achieved with just the blowpipe system and would have required bellows. That helps to confirm the continued operation of the site long into the colonial period, Hosler says.
Years of work went into trying to find ways to date the different deposits of slag at the site. The team also tried archaeomagnetic data but found that the method was not effective for the materials in that particular region of Mexico. But the written historical record proved key to making sense of the wide range of dates, which reflected centuries of use of the site.
Documents sent back to Spain in the early colonial period described the availability of the locally produced copper, and the colonists' successful tests of using it to cast bronze artillery pieces. Documents also described the bargains made by the indigenous producers to gain economic privileges for their people, based on their specialized metallurgical knowledge.
"We know from documents that the Europeans figured out that the only way they could smelt copper was to collaborate with the indigenous people who were already doing it," Hosler says. "They had to cut deals with the indigenous smelters."
Hosler says that "what's so interesting to me is that we were able to use traditional archeological methods and data from materials analysis as well as ethnographic data" from the furnace in a museum in the area, "and historical and archival material from 16th century archives in Portugal, Spain, and Mexico, then to put all the data from these distinct disciplines together into an explanation that is absolutely solid."

Friday, March 27, 2020

Guatemala find reveals early Mayan writing

Complete article
This undated handout picture by the Tak'alik Ab'aj Archaeologial National Park released by the Guatemalan Ministry of Culture and Sports shows a stone at the Tak'alik Ab'aj archaeological site, in El Asintal municipality, Retalhuleu department, Guatemala. A 2,000 year-old stone discovered in Guatemala in 2018 releals the beginning of writing in the Mayan culture, which dominated the south of Mexico and part of Central America, informed experts on March 10, 2020. Guatemalan Ministry of Culture and Sports / AFP.

A 2,000 year old stela recently discovered in Guatemala has revealed examples of the genesis of Mayan writing, according to experts studying the ancient civilization that dominated much of Central America.

Known as Stela 87, the stone was discovered in September 2018 at the Tak'alik Ab'aj archaelogical park in El Asintal, 85 miles (140 kilometers) southwest of the capital. 

The stela, dating from 100 AD, provides an early example of Mayan writing, German expert Nikolai Grube told an event at Guatemala's National Palace of Culture on Tuesday.

"The great importance of Stela 87 is that it is an early example of the development of writing in Mesoamerica," said Grube, speaking by video-link from Mexico.

"Tak'alik Ab'aj was a place of experimentation with writing," he said.

Experts are still trying to decipher the hieroglyphs on the stone, but Grube said that while it provided no "linguistic reading", it showed evidence of a ruler and his titles in "an early Mayan text."

Tak'alik Ab'aj was a city originally inhabited by Olmecs from around 1,500 BC to 100 AD.

Thursday, March 26, 2020

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Neanderthals ate mussels, fish, and seals too

Over 80,000 years ago, Neanderthals were already feeding themselves regularly on mussels, fish and other marine life. The first robust evidence of this has been found by an international research team with the participation of the University of Göttingen during an excavation in the cave of Figueira Brava in Portugal. Dr Dirk Hoffmann at the Göttingen Isotope Geology Department dated flowstone layers - calcite deposits that form like stalagmites from dripping water - using the uranium-thorium method, and was thus able to determine the age of the excavation layers to between 86,000 and 106,000 years. This means that the layers date from the period in which the Neanderthals settled in Europe. The use of the sea as a source of food at that time has so far only been attributed to anatomically modern humans (Homo sapiens) in Africa. The results of the study were published in the journal Science.
The cave of Figueira Brava is located 30 kilometres south of Lisbon on the slopes of the Serra da Arrábida. Today it is located directly on the waterfront, but at that time it was up to two kilometres from the coast. The research team, coordinated by the first author of the study, Professor João Zilhão from the University of Barcelona, found that the Neanderthals living there were able to routinely harvest mussels and fish, and to hunt seals. Their diet included mussels, crustaceans and fish as well as waterfowl and marine mammals such as dolphins and seals. Food from the sea is rich in omega-3 fatty acids and other fatty acids that promote the development of brain tissue.
Until now, it has always been suspected that this consumption increased the cognitive abilities of the human populations in Africa. "Among other influences, this could explain the early appearance of a culture of modern people that used symbolic artefacts, such as body painting with ochre, the use of ornaments or the decoration of containers made of ostrich eggs with geometric motifs," explains Hoffmann. "Such behaviour reflects human's capacity for abstract thought and communication through symbols, which also contributed to the emergence of more organised and complex societies of modern humans".
The recent results of the excavation of Figueira Brava now confirm that if the habitual consumption of marine life played an important role in the development of cognitive abilities, this is as true for Neanderthals as it is for anatomically modern humans. Hoffmann and his co-authors previously found that Neanderthals made cave paintings in three caves on the Iberian Peninsula more than 65,000 years ago and that perforated and painted shells must also be attributed to the Neanderthals.

Wednesday, March 25, 2020

Prehistoric artifacts suggest a neolithic era independently developed in New Guinea

Emergence of a Neolithic in highland New Guinea by 5,000 to 4,000 years ago

New artifacts uncovered at the Waim archaeological site in the highlands of New Guinea - including a fragment of the earliest symbolic stone carving in Oceania - illustrate a shift in human behavior between 5050 and 4200 years ago in response to the widespread emergence of agriculture, ushering in a regional Neolithic Era similar to the Neolithic in Eurasia. The location and pattern of the artifacts at the site suggest a fixed domestic space and symbolic cultural practices, hinting that the region began to independently develop hallmarks of the Neolithic about 1000 years before Lapita farmers from Southeast Asia arrived in New Guinea. 
While scientists have known that wetland agriculture originated in the New Guinea highlands between 8000 and 4000 years ago, there has been little evidence for corresponding social changes like those that occurred in other parts of the world. 
To better understand what life was like in this region as agriculture spread, Ben Shaw et al. excavated and examined a trove of artifacts from the recently identified Waim archaeological site. "What is truly exciting is that this was the first time these artifacts have been found in the ground, which has now allowed us to determine their age with radiocarbon dating," Shaw said. 
The researchers analyzed a stone carving fragment depicting the brow ridge of a human or animal face, a complete stone carving of a human head with a bird perched on top (recovered by Waim residents), and two ground stone pestle fragments with traces of yam, fruit and nut starches on their surfaces. They also identified an obsidian core that provides the first evidence for long-distance, off-shore obsidian trade, as well as postholes where house posts may have once stood.

Thursday, March 19, 2020

Global human genomes reveal rich genetic diversity shaped by complex evolutionary history

A new study has provided the most comprehensive analysis of human genetic diversity to date, after the sequencing of 929 human genomes by scientists at the Wellcome Sanger Institute, the University of Cambridge and their collaborators. The study uncovers a large amount of previously undescribed genetic variation and provides new insights into our evolutionary past, highlighting the complexity of the process through which our ancestors diversified, migrated and mixed throughout the world.
The resource, published in Science (20 March), is the most detailed representation of the genetic diversity of worldwide populations to date. It is freely available to all researchers to study human genetic diversity, including studies of genetic susceptibility to disease in different parts of the world.
The consensus view* of human history tells us that the ancestors of present-day humans diverged from the ancestors of extinct Neanderthal and Denisovan groups around 500,000-700,000 years ago, before the emergence of 'modern' humans in Africa in the last few hundred thousand years.
Around 50,000-70,000 years ago, some humans expanded out of Africa and soon after mixed with archaic Eurasian groups. After that, populations grew rapidly, with extensive migration and mixture as many groups transitioned from hunter-gatherers to food producers over the last 10,000 years.
This study is the first to apply the latest high-quality sequencing technology to such a large and diverse set of humans, covering 929 genomes from 54 geographically, linguistically and culturally diverse populations from across the globe. The sequencing and analysis of these genomes, which are part of the Human Genome Diversity Project (HGDP)-CEPH panel**, now provides unprecedented detail of our genetic history.
The team found millions of previously unknown DNA variations that are exclusive to one continental or major geographical region. Though most of these were rare, they included common variations in certain African and Oceanian populations that had not been identified by previous studies.
Variations such as these may influence the susceptibility of different populations to disease. However, medical genetics studies have so far predominantly been conducted in populations of European ancestry, meaning that any medical implications that these variants might have are not known. Identifying these novel variants represents a first step towards fully expanding the study of genomics to underrepresented populations.
However, no single DNA variation was found to be present in 100 per cent of genomes from any major geographical region while being absent from all other regions. This finding underlines that the majority of common genetic variation is found across the globe.
Dr Anders Bergström, of the Francis Crick Institute and an alumnus of the Wellcome Sanger Institute, said: "The detail provided by this study allows us to look deeper into human history, particularly inside Africa where less is currently known about the timescale of human evolution. We find that the ancestors of present-day populations diversified through a gradual and complex process mostly during the last 250,000 years, with large amounts of gene flow between these early lineages. But we also see evidence that small parts of human ancestries trace back to groups that diversified much earlier than this."
Hélène Blanché, Head of the Biological Resource Centre at the Centre d'Etude du Polymorphisme Humain (CEPH) in Paris, France, said: "The Human Genome Diversity Project resource has facilitated many new discoveries about human history in the past two decades. It is exciting to see that with the latest genomic sequencing technology, these genomes will continue to help us understand our species and how we have evolved."
The study also provides evidence that the Neanderthal ancestry of modern humans can be explained by just one major 'mixing event', most likely involving several Neanderthal individuals coming into contact with modern humans shortly after the latter had expanded out of Africa. In contrast, several different sets of DNA segments inherited from Denisovans were identified in people from Oceania and East Asia, suggesting at least two distinct mixing events.
The discovery of small amounts of Neanderthal DNA in west African people, most likely reflecting later genetic backflow into Africa from Eurasia, further highlights how human genetic history is characterised by multiple layers of complexity. Until recently, it was thought that only people outside sub-Saharan Africa had Neanderthal DNA.
Dr Chris Tyler-Smith, recently retired from the Wellcome Sanger Institute, said: "Though this resource is just the beginning of many avenues of research, already we can glimpse several tantalising insights into human history. It will be particularly important for better understanding human evolution in Africa, as well as facilitating medical research for the full diversity of human ancestries."