The Archaeology News Network

North 'plaza' in Cahokia was likely inundated year-round, study finds

2022-07-21T19:00:00.034+03:00

The ancient North American city of Cahokia had as its focal point a feature now known as Monks Mound, a giant earthwork surrounded on its north, south, east and west by large rectangular open areas. These flat zones, called plazas by archaeologists since the early 1960s, were thought to serve as communal areas that served the many mounds and structures of the city.

The study focused on the north plaza, an expanse at a low elevation that is almost
always inundated with water [Credit: Caitlin Rankin]

New paleoenvironmental analyses of the north plaza suggest it was almost always underwater, calling into question earlier interpretations of the north plaza’s role in Cahokian society. The study is reported in the journal World Archaeology.

Cahokia was built in the vicinity of present-day St. Louis, beginning in about A.D. 1050. It grew, thrived for more than 300 years and was abandoned by 1400. Many mysteries surround the culture, layout and architecture of the city, in particular its relationship to water.

Cahokia was built in a flood plain below the confluence of the Mississippi and Illinois rivers and would have been regularly infiltrated with flowing water, said Caitlin Rankin, a geoarchaeologist at the Illinois State Archaeological Survey who conducted the new research.

“Cahokia is the largest archaeological site in North America, but only about 1% of it has been excavated, so there’s so much about the site that we don’t know,” Rankin said.

Early in her encounters with the city’s layout, Rankin was baffled by the location and height of the north plaza. “It’s a really strange area because it’s at a very low elevation, like the lowest elevation of the site,” she said. “And it’s in an old meander scar of the Mississippi River.”

Two creeks ran through the area, and it likely flooded whenever the Mississippi swelled after heavy rains.

Researchers took samples from nearby wetlands to determine the environmental
history of the north plaza in Cahokia [Credit: Caitlin Rankin]

To investigate the site, Rankin conducted test excavations and extracted sediment cores around the four mounds that define the north plaza.

She also took soil samples in the same meander scar less than 5 kilometers from the plaza and analyzed stable carbon isotopes in these modern soils to determine isotope differences between wetlands, seasonal wetlands and prairie environments.

Comparing these with carbon isotopes from ancient soils chronologically associated with the mounds gave insight into what types of plants had grown there in the past.

“What I learned is that this area remained wet throughout the year,” Rankin said. “There may have been some seasonal dryness, but overall, it was a wetland.”

Her findings challenge previous notions about this site being a plaza, which is generally thought of as a dry open area across which people walk and congregate. "Generally, those places aren't underwater," Rankin said.

How the north plaza was used remains a mystery, she said, but the study adds to the evidence that water was a central element of the city.

Sediments from excavations at Mound 5 reveal that the north plaza was a wetland
prior to, and after, mound construction [Credit: Caitlin Rankin]

"Water was important to the people of Cahokia for a number of reasons," she said. "They had a whole agricultural suite of wetland plants that they domesticated and relied on as food." Water also was essential to their trade with people up and down the Mississippi River. And the cosmological beliefs of many Indigenous groups include creation stories that involve complex interactions with sky, water and earth.

"At Cahokia, you have these mounds emerging from this watery sphere," she said. "And so that was a significant feature that probably resonated with their creation stories and their myths and their worldview."

Author: Diana Yates | Source: University of Illinois at Urbana-Champaign [July 21, 2022]

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Earliest English medieval shipwreck site uncovered off Dorset coast

2022-07-21T18:00:00.041+03:00

Maritime archaeologists from Bournemouth University have uncovered the remains of a medieval ship and its cargo dating back to the 13th century off the coast of Dorset. The survival of the vessel is extremely rare and there are no known wrecks of seagoing ships from the 11th to the 14th centuries in English waters. The discovery makes this the earliest English designated wreck site where hull remains can be seen.

Diver viewing a decorated Purbeck stone gravestone on the 13th century 'Mortar Wreck',
Poole Bay, Dorset [Credit: Bournemouth University]

The ship was discovered in Poole Bay on the edge of the Swash Channel by local charter boat skipper Trevor Small of Rocket Charters who reported the discovery to archaeologists from Bournemouth University. Trevor said: “I was born into a seafaring family. I’ve skippered thousands of sea miles looking for shipwrecks from my home port of Poole. In summer 2020, I discovered what I believed to be an undetected wreck site. Recent storms had revealed something unknown on the seabed. I was granted permission to dive the wreck. The rest is history! I’ve found one of the oldest shipwrecks in England.”

Maritime Archaeologist, Tom Cousins who is part of the team at Bournemouth University assigned to uncover and preserve the wreck said: “Very few 750-year-old ships remain for us to be able to see today and so we are extremely lucky to have discovered an example as rare as this, and in such good condition. A combination of low-oxygenated water, sand and stones has helped preserve one side of the ship, and the hull is clearly visible.”

Bournmeouth University maritime archaeologist diving next to one of the decorative
gravestones on the seabed [Credit: Bournemouth University]

The vessel, known as a clinker ship in its design, is made from overlapping planks of wood and was carrying a cargo of Purbeck stone. The shipwreck is referred to as the ‘Mortar Wreck,’ since much of the cargo contained within the wreck also includes several Purbeck stone mortars, which are large stones used by mills to grind grains into flour.

Purbeck stone is a form of limestone made from densely packed shells of freshwater snails. Quarried on the Isle of Purbeck on the south coast of England, the stone is also referred to as Purbeck marble, due to its ability to be highly polished. Purbeck marble is used in Gothic architecture across Britain and the continent. Other items found in the wreck include a cauldron used to cook food in, which would have been placed directly onto a fire.

Mortar wreck contents [Credit: Bournemouth University]

Two Purbeck marble gravestone slabs were also found in the wreck in remarkably good condition. Purbeck marble gravestone slabs were widely used across the south of England and were exported to Ireland and the continent. One of the slabs features a wheel headed cross, an early 13th century style, while the other features a splayed arm cross, common in the mid-13th century.

The discovery has re-written our understanding of how gravestone slabs were produced according to Brian and Moira Gittos from the Church Monuments society who said: “Even this early stage in the investigation, it has been clearly demonstrated that two cross head designs which were previously thought to be part of a developmental sequence were actually in use at the same time.

Ship crew's couldron [Credit: Bournemouth University]

Further work on the wreck is very likely to greatly enhance our understanding of the work of the medieval Purbeck marblers’.” These were found to be carved, rather than blank slabs which suggests that these were produced as a form of industry. It is believed that the unpolished slabs would have either been carved at a local quarry, or at a workshop.

Duncan Wilson, Chief Executive of Historic England, who has been working closely with the university said: “The 13th century ship with its cargo of medieval Purbeck stone is fascinating because it is the earliest English protected wreck site where hull remains are present.”

Tree ring analysis indicates that the timbers used to construct the hull are from Irish oak trees, felled between 1242-1265.The Irish origin of the timbers doesn’t necessarily mean the ship was constructed in Ireland as Irish oak was widely exported for shipbuilding during the medieval period. One theory is that the ship may have been lost on its way out from the Dorset coast, with its cargo of Purbeck stone.

Rebecca Rossiter, Engagement and Collections Manager at Poole Museum, who will be exhibiting the cargo finds from the Mortar Wreck said: “It’s exciting that finds from the Mortar Wreck will be going on display in one of Poole Museum’s three new maritime galleries. Our new maritime galleries are part of Our Museum Project £4.3m redevelopment of the museum, supported by The National Lottery Heritage fund. They will open to the public in 2024, and local residents and visitors will be able to see some of these incredible finds up close and hear the stories about how the wreck was discovered and excavated from the people involved.”

Source: Bournemouth University [July 21, 2022]

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In search of the lost Parthian city of Natounia

2022-07-20T18:00:00.070+03:00

The mountain fortress of Rabana-Merquly in modern Iraqi Kurdistan was one of the major regional centres of the Parthian Empire, which extended over parts of Iran and Mesopotamia approximately 2,000 years ago. This is a conclusion reached by a team of archaeologists led by Dr Michael Brown, a researcher at the Institute of Prehistory, Protohistory and Near-Eastern Archaeology of Heidelberg University. Together with Iraqi colleagues, Brown studied the remains of the fortress. Their work provides important insights into the settlement structures and history of the Parthians, about whom there is surprisingly little knowledge, emphasises Dr Brown, even though the annals of history record them as a major power. Furthermore, Rabana-Merquly may be the lost city of Natounia.

Excavation of the perimeter wall at the entrance to Rabana valley
[Credit: © Rabana-Merquly Archaeological Project]

Situated on the southwest flanks of Mt. Piramagrun in the Zagros Mountains, the stone fortress of Rabana-Merquly comprises not only the nearly four-kilometre-long fortifications but also two smaller settlements for which it is named. Because of its high position on the mountain, mapping the site was possible only with drones. Within the framework of multiple excavation campaigns conducted from 2009 and most recently between 2019 and 2022, the international team of researchers was able to study the archaeological remains on site.

A) Rabana "sanctuary"; B) staircase; C) iron arrowheads;D) altar (scales = 1m)
(© Rabana-Merquly Archaeological Project) [Credit: M. Brown et al, 2022]

Structures that have survived to this day suggest a military use and include the remains of several rectangular buildings that may have served as barracks. The researchers also found a religious complex possibly dedicated to the Zoroastrian Iranian goddess Anahita. The rock reliefs at the entrance to the fortress are of special significance, along with the geographic location of the fortification in the catchment area of the Lower Zab River, known in antiquity by its Greek name of Kapros.

A) Merquly rock-relief; B) Rabana rock-relief; C) statue from Hatra of King 'tlw/Attalos
of Adiabene (illustrations by M. Brown; © Rabana-Merquly Archaeological Project)
[Credit: M. Brown et al, 2022]

The researchers suspect that Rabana-Merquly may be the lost city of Natounia. Until now, the existence of the royal city known as Natounia on the Kapros, or alternatively as Natounissarokerta, has been documented only on a few coins dating from the first century BC. According to one scientific interpretation, the place name Natounissarokerta is composed of the royal name Natounissar, the founder of the Adiabene royal dynasty, and the Parthian word for moat or fortification. "This description could apply to Rabana-Merquly," states Dr Brown.

A) Mount Piramagrun, showing the location of the main Rabana and Merquly settlements;
B) general plan of Rabana-Merquly (map by M. Brown; © Rabana-Merquly
Archaeological Project) [Credit: M. Brown et al, 2022]

According to the Heidelberg archaeologist, the wall reliefs at the entrance to the fortress could depict the city's founder, either Natounissar or a direct descendant. The researcher explains that the relief resembles a likeness of a king that was found approximately 230 kilometres away in Hatra, a location rich in finds from the Parthian era. The Rabana-Merquly mountain fortress is located on the eastern border of Adiabene, which was governed by the kings of a local dynasty dependent on the Parthians. It may have been used, among other things, to conduct trade with the pastoral tribes in the back country, maintain diplomatic relations, or exert military pressure. "The considerable effort that must have gone into planning, building, and maintaining a fortress of this size points to governmental activities," stresses Dr Brown.

Coin of Natounia, Reverse Inscription: NATOΥN / IEΩN T[ΩN] /
ΠPOC TΩ /KAPΠΩ (Marciak 2013: 162–64)
[Credit: Trustees of the British Museum]

The current research in Rabana-Merquly is being funded by the German Research Foundation as part of priority programme 2176, "The Iranian Highlands: Resilience and Integration of Premodern Societies." The aim of the research project is to investigate Parthian settlements and society in the Zagros highlands on both sides of the Iran-Iraq border. During the latest excavations at Rabana-Merquly, Dr Brown collaborated with colleagues from the Directorate of Antiquities in Sulaymaniyah, a city in the autonomous region of Iraqi Kurdistan. The results of the Heidelberg investigations were published in the journal Antiquity.

Source: Heidelberg University [July 20, 2022]

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Mammals were not the first to be warm-blooded

2022-07-20T14:00:00.040+03:00

Endothermy, or warm-bloodedness, is the ability of mammals and birds to produce their own body heat and control their body temperature.

A warm-blooded mammal ancestor breathing out hot hair
in a frigid night [Credit: Luzia Soares]

This major difference with the cold-blooded reptiles underpins the ecological dominance of mammals in almost every ecosystem globally. Until now, it was not known exactly when endothermy originated in mammalian ancestry. A team of international scientists, including researchers from the University of the Witwatersrand (Wits University) in Johannesburg, South Africa, has found the smoking gun of this key evolutionary event in the inner ears of fossils from South Africa and around the globe.

A new study suggests that endothermy appeared in mammalian ancestors about 233 million years ago, well before the origin of mammals, which occurred about 200 million years ago. This study, titled Inner ear biomechanics reveals Late Triassic origin of mammalian endothermy is published in Nature.

“For the first time, we are able to trace through evolution the direct consequence of the origin of endothermy on the skeletal anatomy of our pre-mammalian ancestors,” says Dr Julien Benoit, Senior Researcher in Palaeontology at the Evolutionary Studies Institute at Wits University. “This is an exciting time for our field of study.”

The intuition

The inner ear is not only the organ of hearing, but also houses the organ of balance: the semicircular canals. The three semicircular canals of the inner ear are oriented in the three dimensions of space and are filled with a fluid that flows in the canals as the head moves and activates receptors to tell the brain the exact three-dimensional position of the head and body. The viscosity, or runniness, of this fluid (called the endolymph) is of paramount importance for the balance organ to efficiently detect head rotation and aid balance.

As for any other fluid, the viscosity of the endolymph changes with body temperature, just like a piece of butter turns from solid to liquid in a warm pan. Because of this physical property, the viscosity of the endolymph would be altered by the evolution of a higher body temperature. However, this change of viscosity cannot be left unchecked because the balance organ would stop working properly. The semicircular canals of the inner ear must adapt to the new viscosity imposed by higher body temperature: they have to change their geometry.

The bony inner ear of a squirrel monkey (in blue) and the soft tissues inside it (in red).
Relations between bony and soft tissue structures have been studied in extant
species to infer inner ear function in fossils and infer whether they
were cold or warm-blooded [Credit: Romain David]

The key intuition of the two lead authors of the discovery, Dr Ricardo Araujo (University of Lisbon) and Dr Romain David (Natural History Museum of Paris), was to realise that this change in the semicircular canals shape would be easy to trace through geologic time using fossils. Pinpointing the species in which this change of geometry occurred would work as an accurate guide to when endothermy evolved: the smoking gun identifying when mammalian ancestors transitioned from cold-blooded to warm-blooded.

“Until now, semicircular canals were generally used to predict locomotion of fossil organisms. However, by carefully looking at their biomechanics, we figured that we could also use them to infer body temperatures. This is because, like honey, the fluid contained inside semicircular canals gets less viscous when temperature increases, impacting function. Hence, during the transition to endothermy, morphological adaptations were required to keep optimal performances, and we could track them in mammal ancestors,” says Dr Romain David, Post-Doctoral Researcher at the Natural History Museum and Lead Author on the paper.

The contribution of Karoo fossils

The team found that the inner ear canals geometry adapted to a relatively abrupt change in endolymph viscosity some 233 million years ago, indicating that the overall body temperature of mammal ancestors became warmer at this time.

Fossils from the South African Karoo played a key role in this discovery, in part because of the wealth of fossils of mammal ancestors that the Karoo-aged rocks have produced in more than a hundred years of study.

South African fossils offer an unbroken record of the evolution of life during an interval of almost 100 million years, documenting the transformation from reptilian-like animals (the therapsids) to mammals in exquisite detail. In addition, because the Karoo was situated closer to the South Pole at that time as a result of continental drift, the warmer body temperature suggested by the geometry of the inner ear cannot be due to an overall warmer climate.

Size differences between inner ears (in grey) of warm-blooded (on the left) and cold-
blooded (on the right) mammal ancestors. Inner ears are compared for animals
of similar body sizes [Credit: Romain David & Ricardo Araujo]

“As the South African climate was colder on average, the change in inner ear fluid viscosity can only have been caused by a generally warmer body temperature in mammalian ancestors,” says Benoit.

Using cutting edge CT-scanning techniques and 3D modelling, the researchers were able to reconstruct the inner ear of dozens of mammalian ancestors from the South African Karoo and elsewhere in the world, and managed to point out exactly which species had an inner ear anatomy consistent with a warmer body temperature, and which ones did not.

A change of paradigmn

Until now the general expectation was that endothermy arose very close to the Permo-Triassic boundary, about 252 million years ago, or perhaps closer to the origin of mammals 200 million years ago. The new results suggest that endothermy appeared in mammalian ancestors some 233 million years ago. This new date is consistent with the recent findings that many of the traits usually associated with “mammalness”, such as whiskers and fur, also evolved earlier than previously expected. More importantly, the results support that the evolutionary transition to warmbloodedness was unexpectedly fast.

“Contrary to current scientific thinking, our paper surprisingly demonstrates that the acquisition of endothermy seems to have occurred very quickly in geological terms, in less than a million years,” says Dr Ricardo Araujo, Junior Researcher at Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, University of Lisbon and Lead Author on the paper. “It was not a gradual, slow process over tens of millions of years as previously thought, but maybe was attained quickly when triggered by novel mammal-like metabolic pathways and origin of fur.”

“The origin of mammalian endothermy is one of the great unsolved mysteries of paleontology”, says Dr Kenneth D. Angielczyk, MacArthur Curator of Paleomammalogy at Field Museum of Natural History, USA and Senior Author on the paper.

“Many different approaches have been used to try to predict when it first evolved, but they have often given vague or conflicting results. We think our method shows real promise because it has been validated using a very large number of modern species, and it suggests that endothermy evolved at a time when many other features of the mammalian body plan were also falling into place.”

Source: University of the Witwatersrand [July 20, 2022]

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Plant study hints evolution may be predictable

2022-07-20T13:30:00.000+03:00

Evolution has long been viewed as a rather random process, with the traits of species shaped by chance mutations and environmental events -- and therefore largely unpredictable.

Similar leaf types evolved independently in three species of plants found in cloud forests of Oaxaca,
Mexico and three species of plants in similar environment in Chiapas, Mexico. This example of
parallel evolution is one of several found by Yale-led scientists and suggests that evolution
may be predictable [Credit: Yale University]

But an international team of scientists led by researchers from Yale University and Columbia University has found that a particular plant lineage independently evolved three similar leaf types over and over again in mountainous regions scattered throughout the neotropics.

The findings provided the first examples in plants of a phenomenon known as "replicated radiation," in which similar forms evolve repeatedly within different regions, suggesting that evolution is not always such a random process but can be predicted.

"The findings demonstrate how predictable evolution can actually be, with organismal development and natural selection combining to produce the same forms again and again under certain circumstances," said Yale's Michael Donoghue, Sterling Professor Emeritus of Ecology & Evolutionary Biology and co-corresponding author. "Maybe evolutionary biology can become much more of a predictive science than we ever imagined in the past."

For the study, the research team studied the genetics and morphology of the plant lineage Viburnum, a genus of flowering plants that began to spread south from Mexico into Central and South America some 10 million years ago. Donoghue studied this same plant group for his Ph.D. dissertation at Harvard 40 years ago. At the time, he argued in favor of an alternative theory in which large, hair-covered leaves and small smooth leaves evolved early in the evolution of the group and then both forms migrated separately, being dispersed by birds, through the various mountain ranges.

The new genetic analyses reported in the paper, however, show that the two different leaf types evolved independently, in parallel, in each of a number of mountain regions.

"I came to the wrong conclusion because I lacked the relevant genomic data back in the 1970s," Donoghue said.

The team found that a very similar set of leaf types evolved in nine of 11 regions studied. However, the full array of leaf types may have yet to evolve in places where Viburnum has only more recently migrated. For instance, the mountains of Bolivia lack the large hairy leaf types found in other wetter areas with little sunshine in the cloud forest in Mexico, Central America, and northern South America.

"These plants arrived in Bolivia less than a million years ago, so we predict that the large, hairy leaf form will eventually evolve in Bolivia as well," Donoghue said.

Several examples of replicated radiation have been found in animals, such as Anolis lizards in the Caribbean. In that case, the same set of body forms, or "ectomorphs," evolved independently on several different islands. With a plant example now in hand, evolutionary biologists will try to discover the general circumstances under which solid predictions can be made about evolutionary trajectories.

"This collaborative work, spanning decades, has revealed a wonderful new system to study evolutionary adaptation," said Ericka Edwards, professor of ecology and evolutionary biology at Yale and co-corresponding author of the paper. "Now that we have established the pattern, our next challenges are to better understand the functional significance of these leaf types and the underlying genetic architecture that enables their repeated emergence."

The study was published in the journal Nature Ecology & Evolution.

Author: Bill Hathaway | Source: Yale University [July 20, 2022]

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The greening ashore

2022-07-20T13:00:00.006+03:00

It took several hundred million years after the formation of Earth some 4½ billion years ago for the initially fiery globe to cool down, allowing the first oceans and land masses to form. The land was barren rock for the next three billion years.

The diversity of flora and fauna as we know them today and the substrate on which they thrive are
thanks to a single species of algae that first went ashore more than 500 million years ago. This
and all other drawings in the publication are by the paper’s first author, Dr. Mona Schreiber
[Credit: HHU/Mona Schreiber]

The blue planet with green continents that we know today did not exist as such in that era. For conditions on the continents were largely hostile to life, with a much higher volcanic activity releasing toxic gases into the atmosphere, a weaker magnetic field than exists today exposing the land more to cosmic rays, and a thinner ozone layer to filter out UV light.

This started changing approximately 500 million years ago when plants began colonizing land. The invasion catalysed a metamorphosis of the hostile environment, accelerating the transformation of the atmosphere, to lay the foundations for the development of life on land as we know it today. All this could only occur once plants, which had only lived in the oceans and inland freshwater, had conquered the continents.

Now Prof. Dr. Sven Gould of the Institute of Molecular Evolution at HHU, Prof. Dr. Stefan Rensing and Dr. Mona Schreiber, a bioinformatics specialist and artist from the University of Marburg, are providing an overview of the current state of research on the plant colonization of land in the journal Trends in Plant Science. Their paper was written in connection with priority programme 2237 "MAdLand" (Molecular Adaptation to Land), funded by the German Research Foundation. The purpose of the MAdLand programme is to explore the beginnings of the evolutionary adaptation of plant organisms to life on land.

The continents only began turning green after a streptophyte alga moved from an aquatic habitat into shore zones before completely transitioning onto land over 500 million years ago, in a process involving numerous molecular and morphological adaptations. Throughout Earth's ongoing changes, plants demonstrated tremendous adaptational capability and altered the climate in crucial fashion, chiefly by fixing carbon dioxide (CO2) on a massive scale.

Terrestrial flora spread in a dominant tour de force, with flowering plants proliferating in explosive fashion; today they comprise over 90% of all known terrestrial plant species. In the history of our planet, land plants have caused several climatic changes, demonstrating tremendous adaptive capability again and again.

Researchers are studying the genomes of species of evolutionary significance with regards to terrestrilization, including mosses, lycopods, ferns and certain algae, in an effort to advance our knowledge of evolutionary processes and molecular adaptation. Their work aims at identifying the mechanisms that served to mitigate hostile life conditions on land, which changed in the course of this evolution. These may indeed prove relevant with regard to climate change, including for crop modification in response to shifting environmental conditions.

Regarding the role of humans in the planet's evolution, the study's senior author Professor Gould elucidates: "Human beings, which have but a brief history compared to plants, are indeed responsible in their own right for significant changes to the planet and its climate. The extreme rapidity of those changes poses a major problem, as nature has little insufficient time to adapt. The pace of human-caused change accelerated when man developed agriculture and animal husbandry, which led to steady population growth and the clearing of ever more land for farming." In this work the collaborating authors analyse human influences on the climate, discussing the adaptability of plant life to the changes that are today unfolding.

Author: Arne Claussen | Source: Heinrich-Heine University Duesseldorf [July 20, 2022]

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New research demonstrates connections between climate change and civil unrest among the ancient Maya

2022-07-19T18:00:00.025+03:00

An extended period of turmoil in the prehistoric Maya city of Mayapan, in the Yucatan region of Mexico, was marked by population declines, political rivalries and civil conflict. Between 1441 and 1461 CE the strife reached an unfortunate crescendo -- the complete institutional collapse and abandonment of the city. This all occurred during a protracted drought. Coincidence? Not likely, finds new research by anthropologist and professor Douglas Kennett of UC Santa Barbara.

Central Mayapan showing the K'uk'ulkan and Round temples [Credit: Bradley Russell]

Writing in the journal Nature Communications, lead author Kennett and collaborators in the fields of archaeology, history, geography and earth science suggest that drought may in fact have stoked the civil conflict that begat violence, which in turn led to the institutional instabilities that precipitated Mayapan's collapse. This transdisciplinary work, the researchers said, "highlights the importance of understanding the complex relationships between natural and social systems, especially when evaluating the role of climate change in exacerbating internal political tensions and factionalism in areas where drought leads to food insecurity."

"We found complex relationships between climate change and societal stability/instability on the regional level," Kennett said in an interview. "Drought-induced civil conflict had a devastating local impact on the integrity of Mayapan's state institutions that were designed to keep social order. However, the fragmentation of populations at Mayapan resulted in population and societal reorganization that was highly resilient for a hundred years until the Spanish arrived on the shores of the Yucatan."

The researchers examined archaeological and historical data from Mayapan, including isotope records, radiocarbon data and DNA sequences from human remains, to document in particular an interval of unrest between 1400 and 1450 CE. They then used regional sources of climatic data and combined it with a newer, local record of drought from cave deposits beneath the city, Kennett explained.

"Existing factional tensions that developed between rival groups were a key societal vulnerability in the context of extended droughts during this interval," Kennett said. "Pain, suffering and death resulted from institutional instabilities at Mayapan and the population fragmented and moved back to their homelands elsewhere in the region."

Round temple and raingod Chac facade at Mayapan [Credit: Bradley Russell]

The vulnerabilities revealed in the data, the researchers found, were rooted in Maya reliance on rain-fed maize agriculture, a lack of centralized, long-term grain storage, minimal investments in irrigation and a sociopolitical system led by elite families with competing political interests.

Indeed the authors argue that "long-term, climate-caused hardships provoked restive tensions that were fanned by political actors whose actions ultimately culminated in political violence more than once at Mayapan."

Yet significantly, a network of small Maya states also proved to be resilient after the collapse at Mayapan, in part by migrating across the region to towns that were still thriving. Despite decentralization, trade impacts, political upheaval and other challenges, the paper notes, they adapted and persisted into the early 16th century. It all points to the complexity of human responses drought on the Yucatan Peninsula at that time -- an important consideration for the future as well as the past.

"Our study demonstrates that the convergence of information from multiple scientific disciplines helps us explore big and highly relevant questions," Kennett said, "like the potential impact of climate change on society and other questions with enormous social implications.

"Climate change worries me, particularly here in the western U.S., but it is really the complexities of societal change in response to climatic perturbations that worry me the most," he added. "The archaeological and historical records provide lessons from the past, and we also have so much more information about our Earth's climate and the potential vulnerabilities in our own sociopolitical systems."

Author: Shelly Leachman | Source: University of California - Santa Barbara [July 19, 2022]

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Study sheds light on penguin evolution

2022-07-19T13:00:00.022+03:00

An international team of 40 researchers analyzed the genomes—the complete set of DNA—of all living and recently extinct penguin species and combined this with the fossil record to gain new insights into the key events and processes that shaped the evolution of these iconic birds. The study, published in Nature Communications, is the first comprehensive genetic study involving extinct and extant (living) penguin species.

Adelie penguin at Rothera Research Station [Credit: Billy Thursfield]

The study revealed that penguin evolution was driven by changes in climate, and ocean currents. Scientists found "signatures" in the penguin genomes that suggest flip-flopping between small populations in climate refugia—regions in which penguins could survive during periods when conditions everywhere else were unfavorable—and population growth and re-colonization during periods when conditions improved. As temperatures dropped, penguins were forced further north, before moving back to the poles as temperatures warmed and habitats became available for re-colonization.

Scientists also identified a suite of genes that potentially underpin some of the adaptations that allow penguins to thrive in some of the most unique environments on Earth, including Antarctica and the Southern Ocean. These adaptations include thermoregulation—the process by which animals maintain the optimum internal temperature—deep diving, underwater vision and factors controlling body size. The researchers discovered that penguins evolved very slowly compared to other birds, but believe that many of these key features associated with an aquatic life occurred early on in penguin evolution.

A pair of Macaroni Penguins (Eudyptes chrysolophus) at Bird Island [Credit: Billy Thursfield]

Professor Richard Phillips, a seabird ecologist at British Antarctic Survey, who is a co-author on the study, says that "although when most people think of penguins, they picture them among ice floes and being chased by leopard seals, penguins evolved to be aquatic creatures before the polar ice sheets formed! Over time, they evolved characteristics that allowed them to colonize a wide range of marine environments from the tropics to Antarctica. This paper provides a step change in our understanding of which genes underpin these different adaptations."

Today, penguins are again under threat from climate change. The scientists say this research into understanding how past climate events impacted past population sizes is crucial in helping us understand how their populations may respond to future climate change.

The study is part of the international Bird Genome 10K project which aims to sequence the genome of all living bird species.

Source: British Antarctic Survey [July 19, 2022]

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When did the genetic variations that make us human emerge?

2022-07-18T16:00:00.023+03:00

The study of the genomes of our closest relatives, the Neanderthals and Denisovans, has opened up new research paths that can broaden our understanding of the evolutionary history of Homo sapiens. A study led by the University of Barcelona has made an estimation of the time when some of the genetic variants that characterise our species emerged. It does so by analysing mutations that are very frequent in modern human populations, but not in these other species of archaic humans.

Credit: University of Barcelona

The results, published in the journal Scientific Reports, show two moments in which mutations accumulated: one around 40,000 years ago, associated with the growth of the Homo sapiens population and its departure from Africa, and an older one, more than 100,000 years ago, related to the time of the greatest diversity of types of Homo sapiens in Africa.

"The understanding of the deep history of our species is expanding rapidly. However, it is difficult to determine when the genetic variants that distinguish us from other human species emerged. In this study, we have placed species-specific variants on a timeline. We have discovered how these variants accumulate over time, reflecting events such as the point of divergence between Homo sapiens and other human species around 100,000 years ago," says Alejandro Andirkó, first author of this article, which was part of his doctoral thesis at the UB.

The study, led by Cedric Boeckx, ICREA research professor in the section of General Linguistics and member of the Institute of Complex Systems of the UB (UBICS), included the participation of Juan Moriano, UB researcher, Alessandro Vitriolo and Giuseppe Testa, experts from the University of Milan and the European Institute of Oncology, and Martin Kuhlwilm, researcher at the University of Vienna.

Predominance of behavioural and facial-related variations

The results of the research study also show differences between evolutionary periods. Specifically, they highlight the predominance of genetic variants related to behaviour and facial structure -- key characteristics in the differentiation of our species from other human species -- more than 300,000 years ago, a date that coincides with the available fossil and archaeological evidence. "We have discovered sets of genetic variants which affect the evolution of the face and which we have dated between 300,000 and 500,000 years ago, the period just prior to the dating of the earliest fossils of our species, such as the ones discovered at the Jebel Irhoud archaeological site in Morocco," notes Andirkó.

The researchers also analysed variants related to the brain, the organ that can best help explain key features of the rich repertoire of behaviours associated with Homo sapiens. Specifically, they dated variants which medical studies conducted in present-day humans have linked to the volume of the cerebellum, corpus callosum and other structures. "We found that brain tissues have a particular genomic expression profile at different times in our history; that is, certain genes related to neural development were more highly expressed at certain times," says the researcher.

Supporting the mosaic nature of the evolution of Homo sapiens

These results complement an idea that is dominant in evolutionary anthropology: that there is no linear history of human species, but that different branches of our evolutionary tree coexisted and often intersected. "The breadth of the range of human diversity in the past has surprised anthropologists. Even within Homo sapiens there are fossils, such as the ones I mentioned earlier from Jebel Irhoud, which, because of their features, were thought to belong to another species. That's why we say that human beings have lived a mosaic evolution," he notes.

"Our results," the researcher continues, "offer a picture of how our genetics changed, which fits this idea, as we found no evidence of evolutionary changes that depended on one or a several key mutations," he says.

Application of machine learning techniques

The methodology used in the study was based on a Genealogical Estimation of Variant Age method, developed by researchers at the University of Oxford. Once they had this estimation, they applied a machine learning tool to predict which genes have changed the most in certain time windows and which tissues these genes may have impacted. Specifically, they used ExPecto, a deep learning tool that uses a convolutional network -- a type of computational model -- to predict gene expression levels and function from a DNA sequence.

"Since there are no data on the genomic expression of variants in the past, this tool is an approach to a problem that has not been addressed until now. Although the use of machine learning prediction is increasingly common in the clinical world, as far as we know, nobody has tried to predict the consequences of genomic changes over time," notes Andirkó.

The importance of the perinatal phase in the brain development of our species

In a previous study, the same UB team, together with the researcher Raül Gómez Buisán, used genomic information from archaic humans. In that study they analysed genomic deserts, regions of the genome of our species where there are no genetic fragments of Neanderthals or Denisovans, and which, moreover, have been subjected to positive pressure in our species: that is, they have accumulated more mutations than would have been expected by neutral evolution. The researchers studied the expression of genes -- i.e., which proteins code for different functions -- found in desert regions throughout brain development, from prenatal to adult stages, covering sixteen brain structures. The results showed differences in gene expression in the cerebellum, striatum and thalamus. "These results bring into focus the relevance of brain structures beyond the neocortex, which has traditionally dominated research on the evolution of the human brain," says Juan Moriano.

Moreover, the most striking differences between brain structures were found at prenatal stages. "These findings add new evidence to the hypothesis of a species-specific trajectory of brain development taking place at perinatal stages -- the period from 22 weeks to the end of the first four weeks of neonatal life -- that would result in a more globular head shape in modern humans, in contrast to the more elongated shape seen in Neanderthals," concludes Moriano.

Source: University of Barcelona [July 18, 2022]

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Prehistoric fish led by their nose

2022-07-15T14:00:00.020+03:00

The evolution of the brain and nervous system in animals has been wound back more than 400 million years, thanks to the examination of fossil remains of ancient lungfish providing a missing link in the emergence of land-living, four-legged animals on Earth.

Cranial endocast of a Palaeozoic lungfish [Credit: A Clement, Flinders University]

An international study, led by Flinders University in Australia, has compared detailed 3D models of cranial endocasts from six Paleozoic lungfish (Dipnoi) fossils to the brain spaces of the surviving sister group of land vertebrates, to better understand brain evolution of lungfishes.

This in turn can aid interpretation of the earliest tetrapods, which later moved from water to land on four legs, says lead author Dr Alice Clement from Flinders University.

The discovery, described in the international journal eLife, showcases the evolutionary history of these lobe-finned fish (Sarcopterygii) and reveals how the olfactory region appears to be more highly plastic than the hindbrain, and undergoes significant elongation in several taxa.

"Our discovery shows that the brains of lungfish have been evolving constantly throughout their 400-million-year history, but it suggests they have likely always relied on their sense of smell rather than vision to navigate their environments. This is quite unlike other fish which use sight much more powerfully," says Dr Clement from the Flinders University Ecology and Evolution (Palaeontology) research lab.

"She says that understanding how lungfish brains have changed throughout their evolutionary history helps an understand of what the brains of the first tetrapods (our land-based ancestors) might have looked like too -- this can give us an idea of which senses were more important than others (such as vision vs olfaction)."

For this study, the researchers from Australia, with co-authors in the UK, Canada and Sweden, used powerful imaging methods to reconstruct these brain models virtually.

South American lungfish [Credit: Getty Images]

Senior author Dr Tom Challands, from the University of Edinburgh in Scotland, says the ongoing work is significant in broad evolutionary and palaeontological science.

"This paper effectively doubles the number of lungfish endocasts known, as their preservation quality is often damaged by a fossil being crushed or broken, and the brain itself has very poor preservation potential and is not currently known in any fossil lungfish," he says.

"Lungfish have persisted for more than 400 million years from the Devonian Period to present day and provide unique insights into the condition of the earliest tetrapods as well as their own evolutionary history."

With the use of X-ray tomography as a palaeontological tool, the cranial endocasts of six Palaeozoic lungfish (Iowadipterus halli, Gogodipterus paddyensis, Pillararhynchus longi, Griphognathus whitei, Orlovichthys limnatis and Rhinodipterus ulrichi) could be studied non-destructively. The fossils come from Australia, the US, Russia and Germany.

The six fossil and two extant taxa were subject to a 12-taxon data set for multivariate morphometric analysis using 17 variables.

"Studying our 'fishy cousins' lungfish continues to help us understand how fish first left the water some 350 million years ago and started to become land animals (tetrapods), and later humans. Perhaps some of their nervous system traits remain in us still," Dr Clements says.

Source: Flinders University [July 15, 2022]

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The hippo and the hydra

2022-07-15T13:00:00.037+03:00

A new study describes the formation of the body axis in the immortal freshwater polyp Hydra. It is controlled by the so-called hippo signalling pathway, a molecular biological process that, among other functions, ensures that our organs do not continue to grow indefinitely. The study was led by the Lunenfeld-Tanenbaum Research Institute in Toronto and the Washington University School of Medicine. The Department of Zoology of the University of Innsbruck, Austria, was significantly involved in the research and provided important data.

A Hydra with a faulty Hippo pathway, leading to deformed tentacles
[Credit: Maria Brooun]

The body structure of most animals is based on an axis that runs from the head to the tail. A big question in developmental biology is how the cells of the first multicellular animals were organized and how this body axis was formed. A new study published in the journal Proceedings of the National Academy of Sciences found that the evolutionary origins of the body axis lie in the so-called Hippo signalling pathway.

A signalling pathway shapes the organs

Signalling pathways are molecular biological processes that serve the communication between cells. Through the production and exchange of certain molecules, cells can recieve, process, and react to information from the environment or the body.

The hippo signalling pathway has an important function in higher animals, such as mammals and birds. It controls the cell division in the forming organs and ensures that they take on their correct size and three-dimensional shape. If the hippo signalling pathway is faulty, tissue thickening can occur, similar to the skin of a hippopotamus -- hence the name.

Electron microscopy shows complex mechanism

A Canadian-US research cooperation, supported by the Department of Zoology at the University of Innsbruck, has described the function of this signalling pathway for the first time in evolutionary ancient organisms. The freshwater polyp hydra served as the model organism for the researchers. It is probable that the Hippo signaling pathway originated in ancient animals such as the hydra.

Dyed muscle fibres of a hydra tentacle. It is deformed because of a faulty Hippo signalling pathway
[Credit: Maria Brooun]

The working group led by Bert Hobmayer at the Department of Zoology has been intensively studying this model organism for years. Using electron microscopy, it provided important data on the internal organization of cells which are controlled by the Hippo signalling pathway.

"Hippo is a complex mechanism that is not yet fully understood in developmental biology," says Hobmayer. "We have now found similar principles of action in the simply built hydras. However, these seem to affect the entire animals."

The Immortal Polyp

The Hydra is a simply built animal, which is considered practically immortal. It permanently renews its tissue, can completely replace entire parts of the body, and form an entire organism from individual cells. The Hydra reproduces asexually by forming a bud from its body, which then grows into a new clone. With each new bud, a new body axis is created.

The study shows that the Hippo signalling pathway affects the rate of cell division throughout the Hydra. This way, it also controls the emergence of new specimens. In addition to controlling tissue growth and asexual reproduction, the Hippo signalling pathway also produces signalling molecules that are necessary for the formation of a normally shaped body axis.

Thus, the researchers have not only come a big step closer to the development of an important signalling pathway. The new knowledge gained on the simply built Hydra also opens up further studies with this model organism.

Source: University of Innsbruck [July 15, 2022]

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DNA from ancient population in Southern China suggests Native Americans' East Asian roots

2022-07-14T18:00:00.040+03:00

For the first time, researchers successfully sequenced the genome of ancient human fossils from the Late Pleistocene in southern China. The data, published in the journal Current Biology, suggests that the mysterious hominin belonged to an extinct maternal branch of modern humans that might have contributed to the origin of Native Americans.

The lateral view of the skull unearthed from Red Dear Cave [Credit: Xueping Ji]

"Ancient DNA technique is a really powerful tool," Su says. "It tells us quite definitively that the Red Deer Cave people were modern humans instead of an archaic species, such as Neanderthals or Denisovans, despite their unusual morphological features," he says.

The researchers compared the genome of these fossils to that of people from around the world. They found that the bones belonged to an individual that was linked deeply to the East Asian ancestry of Native Americans. Combined with previous research data, this finding led the team to propose that some of the southern East Asia people had traveled north along the coastline of present-day eastern China through Japan and reached Siberia tens of thousands of years ago. They then crossed the Bering Strait between the continents of Asia and North America and became the first people to arrive in the New World.

Life reconstruction of the Red Deer Cave People or Mengziren
[Credit: Xueping Ji]

The journey to making this discovery started over three decades ago, when a group of archaeologists in China discovered a large set of bones in the Maludong, or Red Deer Cave, in southern China's Yunnan Province. Carbon dating showed that the fossils were from the Late Pleistocene about 14,000 years ago, a period of time when modern humans had migrated to many parts of the world.

From the cave, researchers recovered a hominin skull cap with characteristics of both modern humans and archaic humans. For example, the shape of the skull resembled that of Neanderthals, and its brain appeared to be smaller than that of modern humans. As a result, some anthropologists had thought the skull probably belonged to an unknown archaic human species that lived until fairly recently or to a hybrid population of archaic and modern humans.

The excavation site of Maludong (Red Deer Cave) [Credit: Xueping Ji]

In 2018, in collaboration with Xueping Ji, an archaeologist at Yunnan Institute of Cultural Relics and Archaeology, Bing Su at Kunming Institute of Zoology, Chinese Academy of Sciences, and his colleagues successfully extracted ancient DNA from the skull. Genomic sequencing shows that the hominin belonged to an extinct maternal lineage of a group of modern humans whose surviving decedents are now found in East Asia, the Indo-China peninsula, and Southeast Asia islands.

The finding also shows that during the Late Pleistocene, hominins living in southern East Asia had rich genetic and morphologic diversity, the degree of which is greater than that in northern East Asia during the same period. It suggests that early humans who first arrived in eastern Asia had initially settled in the south before some of them moved to the north, Su says. "It's an important piece of evidence for understanding early human migration," he says.

Next, the team plans to sequence more ancient human DNA by using fossils from southern East Asia, especially ones that predated the Red Deer Cave people.

"Such data will not only help us paint a more complete picture of how our ancestors migrate but also contain important information about how humans change their physical appearance by adapting to local environments over time, such as the variations in skin colour in response to changes in sunlight exposure," Su says.

Source: Cell Press [July 14, 2022]

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Analysis of fossil tooth brings to light earliest humans from southern Africa

2022-07-14T16:00:00.045+03:00

Fossil tooth analysis by Southern Cross University geochemist Dr. Renaud Joannes-Boyau has played a central role in an international collaboration that has properly identified the earliest humans.

Dr Renaud Joannes-Boyau with a Homo Naledi tooth
[Credit: Southern Cross University]

The new study, published in the journal Proceedings of the National Academy of Sciences, demonstrates that among the 23 specimens analyzed and potentially representing early Homo from southern Africa between 2.5 and 1.4 million years, a maximum of seven of them actually represent Homo, while the others more likely belong to Australopithecus or Paranthropus.

These results have direct implications regarding our interpretations of hominin diversity, paleobiology and ultimately on our understanding of human evolution.

Dr. Renaud Joannes-Boyau used specialist equipment, located at Southern Cross University's Lismore campus, to detect lactation behavior based on geochemical analysis of tooth fossils.

The origins and the biogeographic diversity of the earliest members of genus Homo remain a major topic in paleoanthropology.

These results highlight the importance of correctly identifying the taxon to which a fossil belongs. Otherwise, any misattribution to the genus Homo whereas it represents in fact Australopithecus or Paranthropus would completely bias interpretations on paleobiological aspects, like for example dietary behavior, ecological interactions, hominin paleodiversity, adaptations and evolutionary relationships.

Properly identifying the earliest representatives of our genus Homo is crucial to understand when, where, and how our genus emerged on the African continent. However, there is no consensual definition of the genus Homo, which leads to unending debates regarding the identification of early Homo.

In southern Africa, early Homo remains have been described in several sites (Sterkfontein, Swartkrans, Kromdraai, Drimolen), in geological levels dated between 2.5 and 1.4 million years ago. Some of these specimens were also regarded as potentially representing Australopithecus and/or Paranthropus, complicating the taxonomic attribution of these fossils. These uncertainties preclude any reliable assessment of hominin paleodiversity, as well as the evolutionary relationships between Homo, Australopithecus and Paranthropus, eventually obscuring conditions of emergence of Homo.

Dr. Renaud Joannes-Boyau was part of an international team of researchers whose comprehensive revision of the southern African Early Pleistocene dental remains attributed to early Homo showed that many specimens were misattributed.

Figure 1: Geometric morphometric analyses of the enamel-dentine junction
[Credit: Southern Cross University]

This study is based on geometric morphometric analyses of the enamel-dentine junction (Figure 1), an internal structure of the teeth that has been showed to be a reliable taxonomic proxy to distinguish hominid species up to the sub-species level.

"It is exciting when new techniques, such as microtomography, allow us to extract new and valuable information from fossils that have been in our collections for decades," said Professor Matthew Skinner from the University of Kent.

As a result, among the 23 purported Homo specimens, only four of them (SK 27, SK 847, SKX 21204 and Sts 9) are statistically classified as Homo, and three others preserving more primitive features (StW 80-81, SE 1508 et StW 669) also possibly belong to the human genus.

All the other specimens more likely represent Australopithecus or Paranthropus.

One of the most emblematic remains of southern African paleoanthropology is the mandible SK 15 (Figure 2) that was attributed to Homo erectus for decades, and demonstrated in this study to be more likely related to Paranthropus.

"These quantitative analyses of the enamel-dentine junction shape allowed us to objectively re-evaluate the taxonomy of a number of purported Homo specimens, while also revealing a larger paleodiversity of hominins than previously accepted," said Dr. Clement Zanolli, CNRS researcher at the University of Bordeaux.

Geochemical analyses and elemental mapping were also conducted on two purported early Homo specimens from southern Africa. Both of them were shown to represent more likely Australopithecus (SKX 268) and Paranthropus (KB 5223) using geometric morphometric analyses and interestingly the geochemical signal corroborates these results.

In particular, SKX 268 displays a weaning signal comparable to that reported in Australopithecus and different from what we know in Homo.

Figure 2: Mandible SK 15 is most likely related to Paranthropus and not Homo
[Credit: Southern Cross University]

"Lactation behavior of early hominin, which has been advanced as a versatile adaptive trait to survive challenging ecological niches, could be one of the key features distinguishing Homo from the other hominins," said Dr. Renaud Joannes-Boyau from Southern Cross University.

Dr. Joannes-Boyau explained the confusion around the three genus is because Homo, Australopithecus and Paranthropus were all living at the same time in the same area of southern Africa.

"Australopithecus is likely the ancestor of both Homo and Paranthropus," he said.

"The variation is very minimal between the two but there are some important changes that happens with Homo that makes us so successful that we evolved to over-compete and overtake all the different species.

"Geochemical analysis of the anatomy indicates there is nothing fundamentally different between the genus so it must be something in the behaviour of Homo that allowed the earliest humans to advance."

Source: Southern Cross University [July 14, 2022]

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Evolving to outpace climate change, tiny marine animal provides new evidence of long-theorized genetic mechanism

2022-07-14T13:00:00.023+03:00

Some copepods, diminutive crustaceans with an outsized place in the aquatic food web, can evolve fast enough to survive in the face of rapid climate change, according to new research that addresses a longstanding question in the field of genetics.

Several species of copepods and one ostracod are shown here [Credit: NOAA]

Barely more than a millimeter long, the copepod Eurytemora affinis paddles its way through the coastal waters of oceans and estuaries around the world in large numbers -- mostly getting eaten by juvenile fish, like salmon, herring and anchovy.

"This is a dominant coastal species, serving as very abundant and highly nutritious fish food," says Carol Eunmi Lee, professor in the University of Wisconsin-Madison's Department of Integrative Biology and senior author of a new study on the copepods published in the journal Nature Communications. "But they're vulnerable to climate change."

Ocean salinity, Lee explains, is changing rapidly as ice melts and precipitation patterns change: "These copepods are a saltwater species that now needs to adapt to much fresher water in their environment."

Many copepods (and innumerable other animals) evolved in salty water. As their environment changes, they will have to adjust to maintain their body chemistry … or die off.

"Salinity is a very strong environmental pressure in aquatic habitats," says David Stern, lead author of the study and a former postdoctoral researcher in Lee's lab, now working at the National Biodefense Analysis and Countermeasures Center.

Lee, Stern and the rest of the research team studied how some copepods responded to that pressure. They kept a population of Eurytemora affinis from the Baltic Sea in their lab -- the small crustaceans swimming in water just as salty as their home range and reproducing through several generations.

The researchers then split the copepods into 14 groups of a few thousand each. Four control groups lived out the experiment in the environment like the Baltic. The other 10 groups were exposed to declining salt levels, mimicking the sort of pressure caused by climate change. Each had their water reduced to lower salinity at each new generation (about three weeks for this copepod) for a total of ten generations.

The researchers next sequenced the genomes of each line of copepods at the beginning of their experiment and again after six generations and 10 generations, tracking evolutionary changes across their genomes. The strongest signals of natural selection -- where changes were largest and most common across the groups stressed by falling salinity -- were at parts of the genome believed to be important in regulating ions, such as sodium transporters.

"In saltwater, there are a lot of ions, like sodium, that are essential for survival. But when you get to freshwater, these ions are precious," says Lee. "So, the copepods need to suck them up from the environment and hang on to them, and the ability to do that relies on these ion transporters that we found undergoing natural selection."

At the end of the experiment, the researchers found that copepods with certain genetic combinations of the ion transporter were, repeatedly, more likely to survive through successive generations, even as the salinity of their water decreased. In fact, the same gene variants, or alleles, found in the copepods that survived the salinity decline in the laboratory are also common in the fresher regions of the Baltic Sea.

"With the number of genes we have encoding the traits in our copepods, there's no way we would see the amount of parallelism we did unless something was driving it," says Stern.

The evolution experiment is new evidence of a genetic mechanism called positive epistasis, in which the positive effect of a variant of a gene is amplified when working in combination with other key genes. It's a theory that legendary UW-Madison genetics professor Sewall Wright and others championed nearly a century ago in counterpoint to additive evolution, the idea that the effect of each single gene carries the same weight, and the effects of many genes add up in a linear fashion.

"Computer simulations of evolution in our experimental conditions predict that additive evolution would have given us much greater variation among our 10 lines," adds Stern. "We didn't see that kind of variation."

Epistasis had gone largely untested for lack of experimental tools, but the large amounts of genomic data from modern sequencing and computing simulations made it possible to show positive epistasis at work in parallel evolution and to describe the power of genetics for studying climate change. Stern, Lee and colleagues show in the new study that positive epistasis can drive the parallel evolution of groups of animals by favoring sets of alleles repeatedly through natural selection.

"This copepod gives us an idea of what it takes, an idea of what the conditions are needed, that enable a population to evolve rapidly in response to climate change," says Lee. "It also shows how important evolution is for understanding our changing planet and how -- or even whether -- populations and ecosystems will survive."

Author: Chris Barncard | Source: University of Wisconsin-Madison [July 14, 2022]

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'Everywhere they dig': looters hunt antiquities in Albania

2022-07-12T18:00:00.024+03:00

Shards of ceramics litter the fields of an ancient city in southeastern Albania, where looters have raided the area's highlands in search of antiquities to sell to international traffickers.

Experts say illicit treasure hunters operate with near impunity in Albania
[Credit: Gent Shkullaku/AFP]

Illicit treasure hunters operate with near impunity in the country, stirring outrage among archaeologists over the theft of priceless national heritage that feeds a global black market.

The government says it is working on measures to protect and preserve the sites looters prey on, but so far to little avail—even though removing archaeological artifacts is a crime, as in most countries. Now covered in wild vegetation, the region near present-day Korce was once home to the city of Hija e Korbit, or the "Shadow of the Raven".

The site, nestled against a hillside, has been ravaged in recent years by looters armed with shovels and backhoes searching for rare metals and artefacts. "There are people from all regions who rush to these places," says Axhem Lageshtari, 60, a local resident. "Everywhere they dig. They search in the hope of finding gold, silver or other valuables."

The area gained notoriety after the 1980s discovery of more than 600 silver coins—including some dating back centuries to the rule of Alexander the Great.

Experts tell AFP that illegal excavations have been detected at almost every important archaeological site in the region, which is home to historic necropolises, forts and other remains dating from the Bronze Age to the early Middle Ages.

"The problem is particularly worrying in Hija e Korbit, an important archaeological city that has not yet been explored by archaeologists," laments Rovena Kurti, the head of the department of prehistory at the Tirana Institute of Archaeology. "They damage the site and plunder the heritage," adds Kurti.

'Powerless'

The scavengers often destroy scientific data and remove objects from their environmental context which is needed for experts to understand the site's history, explains Cecile Oberweiler, the former director of the Franco-Albanian mission in Korce.

Various treasures such as coins have been unearthed
[Credit: Gent Shkullaku/AFP]

Northeast of the capital Tirana, the remains of a church from the 11th or 12th century have been disfigured with gaping holes left by looters.

The church of the Holy Virgin Mary was supposed to be protected as a recognised cultural monument, but that failed to stop the trespassers from ransacking the area. "We can give it any name but in truth, it is currently a ruin preyed upon by looters," says archaeologist Skender Mucaj.

The pillaging of the site has been particularly painful for local resident Nora Braia. "I come every Tuesday to pray to the Virgin Mary. She saved the life of my sick son, but I was powerless to save this shelter," Braia, 80, tells AFP through tears, saying she hopes the assailants "will be chased by misfortune".

Experts say not enough is being done legally to stop the looting.

Albania's ministry of culture told AFP that efforts are under way to fight the "illicit trafficking of cultural property", including a national action plan unveiled in 2018 along with initiatives to improve coordination with international organisations.

'A blind eye'

There are no official estimates of the market value of the objects taken from Albania. But researchers are certain that some of the artefacts have fallen into the hands of international traffickers and then been sold in auctions to museums and private collections abroad.

"It is a fight that Albania cannot lead alone, the responsibility also falls on the authorities of other countries who turn a blind eye when these objects are displayed in their museums," said Neritan Ceka, an archaeologist and art historian.

The recent indictment of Jean-Luc Martinez—the former head of the Louvre in Paris who was charged with conspiring to hide the origin of archaeological treasures—highlighted the extent of the illegal trade in antiquities.

French archaeologist Pascal Darcque said the problem was widespread and that museums often do not take seriously the process of vetting objects for sale and their origins.

"Their sale must be blocked and if their geographical origin can be established, the object must be returned," Darcque said.

Author: Briseida Mema | Source: AFP [July 12, 2022]

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Using accurate data when studying Human evolution

2022-07-12T16:00:00.002+03:00

Uncovering the evolution of any set of living creatures is a complex and highly detailed task for scientists, and theories and approaches that may differ over time may indeed change the fossil record. But paleoanthropologist and Stony Brook University Professor Carrie S. Mongle, Ph.D., and co-authors urge investigators to take caution on their findings. They provide researchers investigating the evolutionary past of ancient hominins (a group including humans and our immediate fossil ancestors) an important and foundational message in a recent paper published in Nature Ecology & Evolution. That is—conclusions drawn from evolutionary models are only as good as the data upon which they are based.

The SK 48 cranium of an ancient hominin, Paranthropus robustus, was one of the fossils included
in the analysis of some new claims on human evolution [Credit: Carrie S. Mongle]

In "Modelling hominin evolution requires accurate hominin data," the authors develop a response to a previous research paper that had made some major claims on when the genus Homo emerged based on fossil dates. The team, however, proved that many of the fossil dates from the study were wrong, and they provided data to correct these errors.

"It has become increasingly common in our field for researchers to propose a 'new and exciting' synthesis of evolutionary events that a given group of scientists think overturns our understanding of human evolution," says Mongle, Assistant Professor in the Department of Anthropology and Turkana Basin Institute. "Our paper is meant to draw attention to the issue that we cannot make major claims based on piecemeal compilations of the fossil record and questionable data from literature. We also offer a carefully constrained geochronological dataset for researchers to use for future studies."

Mongle and co-authors found that by re-analyzing the original study with corrected fossil dates, the estimated timing of species divergences differed by as much as 300,000 years from the previously reported estimates. This is important because these estimates are often used to correlate evolutionary transitions with ancient environments and climate change. When estimates are off by this much, it can completely change scientists' interpretations of the evolutionary drivers that made us human.

Mongle and co-authors make the case for evolutionary scientists to develop future total evidence studies when studying human evolution. They conclude that it is "critical to recognize that no algorithm is a replacement for careful comparative anatomy and meticulously constrained geochronology when it comes to interpreting evolutionary trends from the fossil record."

Source: Stony Brook University [July 12, 2022]

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Oldest European salamander fossil, discovered in Scotland

2022-07-12T14:00:00.040+03:00

Fossils discovered in Scotland represent some of the world's oldest salamanders, according to a new study led by UCL researchers.

Artist's impression of Marmorerpeton wakei [Credit: Brennan Stokkermans]

The research team analyzed 166-million-year-old fossils of a type of animal called Marmorerpeton, found in Middle Jurassic rocks on the Isle of Skye.

They found that it has several key salamander traits, but is not part of the modern group of salamanders. Their results are reported in Proceedings of the National Academy of Sciences. The specimen is believed to be the oldest salamander fossil found in Europe.

Marmorerpeton was first described over 30 years ago, but only a few isolated fossil vertebrae and partial jaw bones were found, making it somewhat enigmatic. The new Scottish material adds a wealth of new data, and it also represents a new species: Marmorerpeton wakei, named after the late Professor David Wake, a leading American authority on salamander evolution.

Lead-author Dr. Marc Jones (UCL Cell & Developmental Biology) says that "the fossil is definitely a salamander but unlike anything alive today. It highlights the importance of the fossil record for preserving combinations of anatomical features that do not exist in any living animal."

Marmorerpeton was first described over 30 years ago, but only a few isolated fossil
vertebrae and partial jaw bones were found, making it somewhat enigmatic
[Credit: University College London]

Salamanders, which include newts, are a type of amphibian. Unlike frogs they have a tail and are more variable in size and shape. There are over 700 species found across the northern hemisphere in various freshwater and woodland habitats. They are renowned for their ability to regrow limbs and organs.

This new Scottish fossil salamander had a wide, shallow frog-like head but powerful jaws and distinctive, prominent projections behind the eyes. The skull roof bones show that it was ornamented like that of a crocodile, setting it apart from modern salamanders. The limb bones and deep tail of Marmorerpeton wakei suggest this salamander was aquatic, perhaps using its wide jaws to catch prey by suction feeding, similar to the lifestyle seen in the modern hellbender of North America.

Commenting on the appearance of Marmorerpeton wakei, Dr. Jones says that "the big bony projections behind the eye were a bit unexpected but smaller projections do exist in fossil salamanders from slightly younger rocks. Their purpose remains unknown."

Modern salamanders have been extensively studied to understand development, regeneration, and toxins. However, their early evolution is still very poorly understood. The study included a detailed survey of modern salamander anatomy which informed the subsequent analyses.

Simplified evolutionary tree of amphibians showing how Marmorerpeton is probably related to
other salamanders. Ma = millions of years ago [Credit: Silhouettes are from Phylopic.org
and originals by Marc Jones]

Many previous studies of fossil salamanders have relied heavily on fossils from the Late Jurassic period, found in Kazakhstan, belonging to the genus Karaurus. As new fossils are found that predate this—such as Marmorerpeton—they provide a more complete understanding of how early salamanders evolved.

Senior-author Professor Susan Evans (UCL Cell & Developmental Biology) who first described Marmorerpeton in 1988 says that "the origin and early history of modern amphibian groups remains mysterious and new fossils like this one are key to developing a better understanding of amphibian evolution."

"In theory, the Skye salamander should give us a clue as to what the ancestors of modern salamanders looked like. However, it could be that they are a highly specialized off-shoot."

Senior co-author Professor Roger Benson (University of Oxford) says that "the fossil site on Skye is proving to be a treasure trove for our understanding of the Middle Jurassic fauna and ecosystems, and is helping to fill gaps in the fossil record of many animal lineages including mammals, reptiles and amphibians."

Modern salamander diversity. Top row: Amphiuma; Bolitoglossa; Andrias; Middle row:
Necturus; Plethodon; Desmognathus; Bottom row: Triturus; Eurycea; Salamandr
[Credit: See individual images]

Dr. Jones added that "several fossil salamanders are known from the Jurassic and Cretaceous of China. These were thought to represent early members of modern groups, but our new analyses suggest they might not be part of specific groups as some of their characteristics are found more widely than previously thought."

The details of the new Scottish fossils of Marmorerpeton wakei were only revealed thanks to microCT scanning, which was used to digitize the bones embedded within in the rock. This technology provides a powerful tool in revealing bones hidden for millions of years. One specimen, collected in 2016, was found to be part of a specimen collected in 1971 but left undescribed until now. The digital models are now freely available for others to examine or 3D print.

Source: University College London [July 12, 2022]

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Entombed together: Rare fossil flower and parasitic wasp make for amber artwork

2022-07-11T14:00:00.018+03:00

Oregon State University fossil research has revealed an exquisite merger of art and science: a long-stemmed flower of a newly described plant species encased in a 30-million-year-old tomb together with a parasitic wasp.

Oregon State University fossil research has revealed an exquisite merger of art and science: a long-
stemmed flower of a newly described plant species encased in a 30-million-year-old tomb
together with a parasitic wasp [Credit: George Poinar Jr., Oregon State University]

"Based on interests, background and current environment, everybody has their own way of interpreting visual images in the natural world," said George Poinar Jr. of the OSU College of Science. "Thus an organism can be described, given a scientific name and then stored away in a taxonomic hierarchy. The same organism can be regarded as an art object and even assigned to a particular art period."

The study by Poinar, published in Historical Biology, reports the first description of a fossil flower of the Euphorbiaceae family in amber, in this case amber from the Dominican Republic, home to some of the world's clearest fossilized tree resin.

Members of Euphorbiaceae, also known as the spurge family, grow worldwide, with 105 of its 300 genera, and 1,800 species, found in tropical regions of the Americas.

"Fossil flowers of members of this family are quite rare," Poinar said. "I could only find one previously known fossil, from sedimentary deposits in Tennessee."

Examples of members of this family include the rubber tree, the castor-oil plant and the poinsettia. Many members contain a milky latex while some species are useful as a source of oil or wax.

Poinar, an international expert in using plant and animal life forms preserved in amber to learn about the biology and ecology of the distant past, named the new flower Plukenetia minima. It's the first record of the genus Plukenetia on the island of Hispaniola, home to Haiti and the Dominican Republic, and also the first fossil record of the genus.

Poinar said the mature female flower is noteworthy for its small size but lengthy stalk, which at the tip has four distinct capsules.

The wasp, Hambletonia dominicana, was described by Poinar as a new species in a separate paper published in 2020 in Biosis: Biological Systems. It's an encyrtid, a group of wasps known for attacking a wide range of insects.

In the current study, the flower has already bloomed and contains four maturing seed pods or capsules. One of the pods contains a developing fly larva.

"In many cases, unrelated organisms become entombed together in amber just by chance," Poinar said. "But I feel that in this case, the wasp was attracted to the flower, either for obtaining nectar or in attempts to deposit an egg on the capsule that contains the fly larva."

The wasp egg would then hatch, enter the pod and devour the fly larva, Poinar said, enabling the wasp to survive in the ecological niche created by the vegetation and flower heads of Plukenetia.

"Both of the fossils can be associated with two 20th-century art movements that appeared in fine art, design and architecture," Poinar said. "The 'petite' flower represents the Art Nouveau style that emphasizes elegant curves and long lines. The 'dancing' wasp represents the Art Deco style that stresses sharp angles and decorative shapes."

Author: Steve Lundeberg | Source: Oregon State University [July 11, 2022]

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Paleobiology: Complex family relationships

2022-07-11T13:00:00.005+03:00

An international team of researchers led by LMU paleontologist Bettina Reichenbacher has managed to classify fossils of one of the most species-rich fish groups into a family tree for the first time.

Rhyacichthys guilberti [Credit: © Philippe Keith]

Gobies are one of the most species-rich groups of ocean and freshwater fish. Found throughout the world in around 2,300 species divided between eight families, the Gobioidei suborder is highly diverse. Understanding how, why, and when this diversity came about is very complicated. In helping to answer these questions, goby fossils can make a definite contribution. After all, they are direct evidence of goby diversity many millions of years ago.

First, however, scientists had to find out whether the fossil gobies belong to one of today's families -- and if so, which one. And this problem could not be solved -- at least sufficiently -- before now, as the individual families of goby have acquired only few new traits, so-called apomorphies, in the course of their evolution. And few of these important traits generally survive in fossil gobies. For this reason, most fossil gobies could not be assigned to a family before now, or only with a high degree of uncertainty.

To solve this problem, an international team of researchers led by LMU paleontologist Bettina Reichenbacher took the existing molecular family tree of the gobies and supplemented the molecular data with morphological data.

Through this technique, the researchers were able to then "add" fossil goby species to the established family tree of today's gobies. Or, to put it another way, the fossils were "placed" in the family tree of their current descendants. Some of the fossils ended up in a place in the family tree where previous studies had indicated they might belong; others ended up in entirely new, sometimes surprising family surroundings.

"We see our approach as groundbreaking for all further phylogenetic investigations into fossil gobies," says Reichenbacher. The researchers hope that this will yield a better understanding of the evolutionary history of these fascinating fish.

The study is published in PLOS ONE.

Source: Ludwig-Maximilians-Universitat Munchen [July 11, 2022]

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500-million-year-old fossilized brains of stanleycaris prompt a rethink of the evolution of insects and spider

2022-07-08T14:00:00.019+03:00

ROM (Royal Ontario Museum) revealed new research based on a cache of fossils that contains the brain and nervous system of a half-billion-year-old marine predator from the Burgess Shale called Stanleycaris. Stanleycaris belonged to an ancient, extinct offshoot of the arthropod evolutionary tree called Radiodonta, distantly related to modern insects and spiders. These findings shed light on the evolution of the arthropod brain, vision, and head structure. The results were announced in the paper, "A three-eyed radiodont with fossilized neuroanatomy informs the origin of the arthropod head and segmentation," published in the journal Current Biology.

Life reconstruction of Stanleycaris [Credit: ROM]

It's what's inside Stanleycaris' head that has the researchers most excited. In 84 of the fossils, the remains of the brain and nerves are still preserved after 506 million years. "While fossilized brains from the Cambrian Period aren't new, this discovery stands out for the astonishing quality of preservation and the large number of specimens," said Joseph Moysiuk, lead author of the research and a University of Toronto (U of T) PhD Candidate in Ecology and Evolutionary Biology, based at the Royal Ontario Museum. "We can even make out fine details such as visual processing centers serving the large eyes and traces of nerves entering the appendages. The details are so clear it's as if we were looking at an animal that died yesterday."

The new fossils show that the brain of Stanleycaris was composed of two segments, the protocerebrum and deutocerebrum, connected with the eyes and frontal claws, respectively. "We conclude that a two-segmented head and brain has deep roots in the arthropod lineage and that its evolution likely preceded the three-segmented brain that characterizes all living members of this diverse animal phylum," added Moysiuk. In present day arthropods like insects, the brain consists of protocerebrum, deutocerebrum, and tritocerebrum. While the difference of a segment may not sound game-changing, it in fact has radical scientific implications. Since repeated copies of many arthropod organs can be found in their segmented bodies, figuring out how segments line up between different species is key to understanding how these structures diversified across the group. "These fossils are like a Rosetta Stone, helping to link traits in radiodonts and other early fossil arthropods with their counterparts in surviving groups."

In addition to its pair of stalked eyes, Stanleycaris possessed a large central eye at the front of its head, a feature never before noticed in a radiodont. "The presence of a huge third eye in Stanleycaris was unexpected. It emphasizes that these animals were even more bizarre-looking than we thought, but also shows us that the earliest arthropods had already evolved a variety of complex visual systems like many of their modern kin" said Dr. Jean-Bernard Caron, ROM's Richard Ivey Curator of Invertebrate Palaeontology, and Moysiuk's PhD supervisor. "Since most radiodonts are only known from scattered bits and pieces, this discovery is a crucial jump forward in understanding what they looked like and how they lived," added Caron, who is also an Associate Professor at the U of T, in Ecology & Evolution and Earth Sciences.

In the Cambrian Period, radiodonts included some of the biggest animals around, with the famous "weird wonder" Anomalocaris reaching up to at least 1 meter in length. At no more than 20 cm long, Stanleycaris was small for its group, but at a time when most animals grew no bigger than a human finger, it would have been an impressive predator. Stanleycaris' sophisticated sensory and nervous systems would have enabled it to efficiently pick out small prey in the gloom.

With large compound eyes, a formidable-looking circular mouth lined with teeth, frontal claws with an impressive array of spines, and a flexible, segmented body with a series of swimming flaps along its sides, Stanleycaris would have been the stuff of nightmares for any small bottom dweller unfortunate enough to cross its path.

About the Burgess Shale

For this research, Moysiuk and Caron studied a previously unpublished collection of 268 specimens of Stanleycaris. The fossils were primarily collected in the 1980s and 90s from rock layers above the famous Walcott Quarry site of the Burgess Shale in Yoho National Park, B.C., Canada, and are part of the extensive collection of Burgess Shale fossils housed at ROM.

The Burgess Shale fossil sites are located within Yoho and Kootenay National Parks and are managed by Parks Canada. Parks Canada is proud to work with leading scientific researchers to expand knowledge and understanding of this key period of earth history and to share these sites with the world through award-winning guided hikes. The Burgess Shale was designated a UNESCO World Heritage Site in 1980 due to its outstanding universal value and is now part of the larger Canadian Rocky Mountain Parks World Heritage Site.

Fossils of Stanleycaris can be seen by the public in the new Burgess Shale fossil display in the Willner Madge Gallery, Dawn of Life at ROM.

Source: Royal Ontario Museum [July 08, 2022]

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Unlocking the secrets of the ancient coastal Maya

2022-07-07T18:00:00.012+03:00

Georgia State University anthropologist Dr. Jeffrey Glover grew up in metro Atlanta, but speaking to him, it sounds like his heart is in Quintana Roo. This part of Mexico's Yucatan Peninsula has been the home base for an expansive research project spanning more than 10 years. His research there with Dr. Dominique Rissolo, a maritime archaeologist at UC San Diego's Qualcomm Institute, has uncovered thousands of artifacts that help them shed new light on the ancient Maya people who lived along this stretch of coast.

View of excavation in progress [Credit: Georgia State University]

Glover and Rissolo are working with an interdisciplinary and international team of researchers to uncover new insights about the dynamic interplay between social and natural processes that shaped life for these ancient, Maya people over the last 3,000 years. The team has just released a new article in the Journal of Island and Coastal Archaeology summarizing their findings to date.

"The Proyecto Costa Escondida," which translates into English as the 'hidden coast' project, has focused on the ancient Maya port sites of Vista Alegre and Conil. "We chose the project name because, the coast is literally hidden behind mangroves. We've canoed the coastline and you've really got to snake back to get to the site," Glover said. "But at the same time, and more importantly, this region has been hidden from scholarship -- there just hadn't been a lot of work done there until we arrived."

Jeffrey Glover discusses archaeology with local students from Chiquila. When in the field, PCE team
members make every effort to engage the local community about their work and what the project is
learning about the rich history of the region. This takes the form of talks at local schools or field
trips to the excavation site as well as efforts to get a community museum constructed
[Credit: Georgia State University]

To date, the work has produced a wealth of knowledge about maritime Maya civilization since 800 BCE (Before Common Era). Glover, an associate professor of Anthropology, is using an historical ecology framework to better understand the dynamic relationship between humans and the environment at the ancient Maya port sites of Vista Alegre and Conil.

"This is about how people respond to change," said Dr. John Yellen, program director for archeology at the U.S. National Science Foundation, which helped fund the research. "Through the lens of historical ecology, this broad team of researchers has shown how Maya adapted over centuries to a wide range of environmental changes. This insight into one society's long-term adaptation to coastal environments provides a fruitful model for studying such interactions across many cultures."

These are some of the oldest artifacts recovered by PCE members at Vista Alegre. Based on the style
of these artifacts, they date to the Middle Preclassic period (800 – 400 BC). This is the time period
when people first settled at Vista Alegre. Even more interesting, is that figurines were not often found
during this time period in the local area but were more common in the southern parts of the Maya
area (modern day Belize and Guatemala). These finds indicate that from its inception, Vista Alegre
was tied into broader networks via the coast than neighbouring inland sites
[Credit: Georgia State University]

This region lies along Yucatan's north coast, some hours from popular tourist attractions like Cancun and well-known archaeological sites like Chichen Itza and Tulum.

"What's remarkable about our study area is that it represents one of the least developed coastlines on the northern Yucatan Peninsula," said Rissolo, who was recently featured in a video series about the Maritime Maya. "When trying to understand the ancient maritime cultural landscape of the so-called 'Riviera Maya,' for example, your perspective is obscured by all-inclusive resorts, golf courses and theme parks. The shores of the Laguna Holbox, on the other hand, are still largely wild and offer a more unobstructed view into the region's past."

This nearly intact dish was found with the burial of a 40-45 year old woman at Vista Alegre. Based
on the style of the pot and radiocarbon dates from the burial, the dish and associated burial date to
between 400 and 250 BC. Particularly interesting are the designs on the dish. There are four sets
of four lines along the interior sides of the dish and three dots in the middle of the pot. These
numbers are not random and correspond to key concepts in the ancient Maya worldview. The
world is divided into four parts linked to the passage of the sun and at the center of the universe
are the three hearth stones of creation. These can still be seen in the night sky in the belt
of the constellation we call Orion. For the ancient Maya, Orion represented the turtle
that supported the world [Credit: Georgia State University]

The site of Vista Alegre is a small island surrounded by mangroves that lies along the southern shore of the Holbox Lagoon (also called Conil or Yalahau Lagoon). Glover describes Vista Alegre as what was probably once a small, bustling port. Here, they've discovered and recorded as many as 40 rock-filled platforms that served as the foundation for perishable pole and thatch buildings. The largest is a pyramidal structure that stands about 13 meters -- or nearly 43 feet -- tall. Glover believes this probably served as a temple and a lookout where the site's inhabitants could see if anyone was approaching by sea. Conil, on the other hand, is a much more expansive site located beneath the modern town of Chiquila and was encountered by early Spanish conquistadors who described it as a town of 5,000 houses.

Researchers have identified tens of thousands of artifacts and ecofacts (animal and plant remains that speak to past diets), which have helped improve our understanding of how the landscape has changed over time, how the people lived, and how they dealt with challenges not unlike those faced by people today, such as: rising sea levels and changing political and economic systems. "We are coordinating and synthesizing all the different datasets that we have, which gives us a wider-angle picture," Glover said.

This is a ceramic net weight. This artifact started its life as part of a piece of pottery. When that pot
broke, the inhabitants of Vista Alegre repurposed the sherd (a piece of ceramic) by carving notches
in its ends to be used (along with a bunch of other ones) as weights for a casting net. As indicated
by the faunal (animal bone) remains recovered from Vista Alegre, the past inhabitants were reliant
on the near shore resources of the Yalahau lagoon for most of their diet (fish, shark, rays,
and shellfish) [Credit: Georgia State University]

The project, which has been funded by the National Science Foundation (NSF)and the National Oceanic and Atmospheric Administration (NOAA), combines traditional archaeological techniques (think digging with a small hand trowel or shovel) with new, high-tech practices for land and sea. Glover says it is a matter of making the most out of the materials at hand.

"Archaeology requires a broad knowledge of the latest scientific techniques mixed with a strong reliance on 'MacGyvering,' Glover said. "We often utilize rustic equipment combined with high-tech tools. On any given day, we might find ourselves in a small dinghy borrowed from the local community out of which we are running marine geophysical survey equipment or pounding PVC tubes into the sediments with a homemade fencepost driver."

This obsidian (volcanic glass) blade from Vista Alegre provides valuable clues to past trade networks
. The obsidian can be traced based on its chemical composition to the source where the obsidian
originated. In the case of this blade, it came from an obsidian source in the highlands of Guatemala.
Other obsidian materials at Vista Alegre come from as far away as central Mexico (near modern
day Mexico City) and provide us with key pieces of evidence to reconstruct ancient trade
networks and to track how they changed over time [Credit: Georgia State University]

The complex work of marine geoarchaeology was spearheaded by Dr. Beverly Goodman-Tchernov and Dr. Roy Jaijel of the University of Haifa in Israel. The core samples include sediment from the coastline and give researchers a better idea of how the coastline has changed over time by looking at a host of different datasets. In particular, the remains of tiny creatures (foraminifera) are preserved in the cores. These creatures lived in very specific environments, so by finding certain species of foraminifera, the team can reconstruct what the coastal environment was like. Instead of being hidden as it is today, Vista Alegre was most likely once more open and purposely built on a peninsula that jutted into the lagoon making it a more obvious destination for ancient canoe-based traders.

Along with paleo-coastline reconstruction, Dr. Patricia Beddows of Northwestern University has been combing research on the modern hydrological system with oxygen isotope values from the core sediments to study how access to freshwater changed over time as a result of rising sea-levels. The team has to bring all of their drinking water with them to the site, so they are keenly aware what a limiting factor freshwater access could have been for past peoples. One idea is that there were springs near the site in the past that have been effectively drowned by rising sea level. To try to identify freshwater seeps (that are about two degrees Celsius cooler than the ocean water) the team is using a drone equipped with a thermal camera to identify areas that might represent past sources of freshwater.

The team also uncovered tens of thousands of pieces of pottery and hundreds of pieces of obsidian (volcanic glass used to make tools that can be traced to its original geologic location), which reveal these coastal peoples were involved in extensive trade. Glover says the diversity of these artifacts stands out when compared to that of nearby, inland sites. The research team believes the archaeological data reinforce the idea that these coastal peoples had much broader and more cosmopolitan connections because they were part of long-distance, canoe-based trade networks.

These trade connections are most evident about 1,000 years ago when researchers see a major realignment and expansion in international trade associated with the emergence of Chichen Itza as a powerful religious, political, and economic city. "Strong evidence of this realignment comes from the obsidian data which reveals greater connections to parts of central Mexico, near modern day Mexico City" Glover said.

This carved serpent head is what first attracted Glover and Rissolo to Vista Alegre. Based on the style
of the carving, the serpent head dates to the Postclassic period (AD 1250 – 1521) and would have
been one of a pair that marked the balustrades on each side of the stairs that led up the main
pyramidal structure at the site. While the Postclassic is a time period when Vista Alegre’s
importance as a coastal port site had faded, the site still held ritual significance as
evidenced by the serpent head and other ritual offerings dating to this time period
[Credit: Georgia State University]

Many of these artifacts come from poring over the detritus -- or garbage -- left behind by this past civilization, Glover says this is often an archaeologist's goldmine. Mixed with the pottery and obsidian, the research team found items like spindle whorls, that would have been used to make cotton thread which could have been traded as bolts of cloth or used for fishing lines or nets.

When asked what is missing, Rissolo said "We would love to find an intact ancient Maya trading canoe! It's possible that such a vessel may be preserved beneath the muddy bottom of the bays surrounding Vista Alegre. We would learn so much about these legendary watercraft."

This ceramic stamp would have been used by the ancient inhabitants of Vista Alegre to impress designs
on paper and/or articles of clothing. PCE members have also recovered evidence of the tools needed
to make paper (which one can imagine was important when keeping track of the comings
and goings of international cargo) [Credit: Georgia State University]

The team also discovered an array of natural materials, including more than 20,000 animal bones, from sharks, rays, turtles and marine gastropods (gastropods include animals like conchs and whelks which have been studied by another project leader, Dr. Derek Smith). The team is working closely with Mexican archeologists at the Autonomous University of Yucatan in Merida, Mexico to analyze the animal remains and burial sites that have been discovered.

Research came to a halt during much of the pandemic, but after months of excavations and discovery of so many artifacts, the team is still working to analyze their findings. Glover said they are also in discussions with local leaders in Mexico to create a community museum to highlight the region's rich cultural and natural history.

This is a collection of shell beads and other personal adornments recovered from Vista Alegre. One can
see examples of finished shell beads, a tiger shark tooth pendant, and unfinished shell beads. The
unfinished shell beads are the most interesting to PCE members because that indicate that the
production of shell beads was happening on site [Credit: Georgia State University]

Often, when people think about the ancient Maya, they may picture some sudden, cataclysmic event that upended daily life and led to end of this past, advanced civilization. Glover notes that this could not be further from the truth. Maya peoples are alive and well today in the Yucatan, Belize, and Guatemala. While the 'collapse' of Maya kingdoms between 800 and 900 CE often gets blown out of proportion in popular media, that does not mean that were not changes in settlements over time.

"I think it's a story, not of a sudden or mass exodus, but a shift over time," Glover explained, "and to understand these shifts we must understand the complex interplay of environmental and cultural factors, which is what our research is revealing."

This is one of the most special finds the project has recovered to date. The engraved shell plaque,
which would have been worn by someone, depicts two central seated figures facing each other,
each holding a banner or standard in their left hand. A third individual (depicted in smaller
scale) is seated behind the principal figure on the left side of the scene. The scene exemplifies
the interpersonal interactions behind long-distance coastal exchange networks, and the
artifact could have been an emblem marking the wearer as a member of a specific
trade group or guild [Credit: Georgia State University]

The research also highlights the specific lifestyles and adaptive strategies needed to live in a dynamic coastal environment and how this fostered a shared identity amongst coastal Maya communities. "Our research gives us some idea of the shared challenges that coastal peoples faced -- rising sea-levels, diminished freshwater, changing economic and political systems -- and they probably leaned on one another, Glover said. "In some ways, I think it might have been easier to hop in your canoe and paddle down the coast to seek help than it was to walk over land."

"The past, just like the present is not static, and these people were constantly having to make decisions. Sometimes those decisions meant sticking it out, and sometimes they meant re-establishing their lives right down the coast. This new article is a great summation of what we have learned to date. But, you know, there's always more to be done, and we certainly have plans to continue." Glover said.

Later this year, the team will start a new project with Dr. Tim Murtha, a colleague at University of Florida, to conduct a light detection and ranging (LIDAR) survey. They will collect detailed elevation data that can reveal the distribution of ancient Maya settlements like house mounds or pyramids. While not focused on the coast, the project will help the team better understand the relationship between inland and coastal communities.

On this project, Glover and Rissolo teamed with Dr. Patricia Beddows (Northwestern University), Dr. Beverly Goodman (University of Haifa), Dr. Derek Smith (University of Washington), and others under the auspices of Mexico's National Institute of Anthropology and History (INAH).

More information on the project can be found at: http://costaescondida.org

Author: Noelle Toumey Reetz | Source: Georgia State University [July 07, 2022]

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Early stone tools were not rocket science

2022-07-06T19:00:00.006+03:00

Archaeologically excavated stone tools – some as much as 2.6 million years old – have been hailed as evidence for an early cultural heritage in human evolution. But are these tools proof that our ancestors were already becoming human, both mentally and culturally?

One participant of the study—who was naive to stone tools as well as any of their production
techniques—uses the so-called bipolar technique. The resulting tool is seen centrally
in the lower right [Credit: William D. Snyder et al, 2022]

Dr. Claudio Tennie und William Snyder from the Department of Early Prehistory and Quaternary Ecology at the University of Tubingen (Germany) have tested this traditional interpretation in a study funded by the European Research Council. They draw a different conclusion: as shown by an experimental study, the earliest techniques for making stone tools can be spontaneously reinvented even without cultural transmission. They therefore are not evidence for the beginning of human culture, which possibly may have started much later, the researchers judge.

Tools made from scratch

The authors asked 28 study participants (local adults, who did not study archaeology) to open a box containing monetary rewards. Participants were free to use provided raw materials – a painted glass hemisphere, a medium sized river pebble and a large granite block – in whatever manner they deemed suitable to break a rope that kept the box shut.

They were not given any information, let alone demonstrations and 25 participants proved – via post-test questionnaires – to have been naive at start of test with regard to production techniques of early stone tools. Despite their naivety, the majority innovated at least one of these techniques and proceeded to make and use the resulting tools to cut the rope locking the puzzle box. The authors found that every single production technique of early stone tools was thus re-innovated on the spot – from scratch – across the naive participants.

2.6 million years old (A) and 1.7 million years old stone tools and an example of a result
of the current experiment with subjects without prior knowledge (artifact C)
[Credit: William D. Snyder et al, 2022]

“These data contradict earlier claims that learning how to make any stone tools must be inherently difficult and that it therefore is impossible to do in the absence of models to copy”, says Claudio Tennie. “If the earliest stone tools in the human record really had been the first cases of human culture, then they should resist spontaneous innovation – they should not come about anew ‘from scratch’, in the absence of cultural transmission.”

“When we asked other researchers about it before revealing our results, most did not predict this outcome. They strongly believed that all stone tool making requires copying. But it does not,” says Tennie.

“That stone tools existed 2,6 million years ago is no longer reliable ‘smoking gun’ evidence that our ancestors in the earliest Stone Age had culture like our own” Snyder summaries. “We must now look at much later time periods for the origin of modern human culture.”

The study was published in Science Advances.

Author: Antje Karbe | Source: Universitaet Tubingen [July 06, 2022]

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New genetic research on remote Pacific islands yields surprising findings on world's earliest seafarers

2022-07-06T18:00:00.005+03:00

New genetic research from remote islands in the Pacific offers fresh insights into the ancestry and culture of the world's earliest seafarers, including family structure, social customs, and the ancestral populations of the people living there today.

Guam (pictured) was one of the Pacific islands that scientists believe maintained a matrilocal
population structure some 2,500 to 3,500 years ago [Credit: David Burdick, NOAA]

The work, described in the journal Science, reveals five previously undocumented migrations into a subregion of this area and suggests that about 2,500 to 3,500 years ago early inhabitants of these Pacific islands -- including Guam in the northern region and Vanuatu in the southwest -- had matrilocal population structures where women almost always remained in their communities after marriage while men more often moved out of their mothers' community to live with that of their wives'.

The practice is different from that of patrilocal societies where women are overwhelming the ones to leave their own community. These findings support the idea that the world's earliest seafarers were organized through female lineages.

The results come from a genome-wide analysis on 164 ancient individuals from 2,800 to 300 years ago as well 112 modern individuals. It was published by a team of researchers co-led by Harvard geneticists David Reich and Yue-Chen Liu, Ron Pinhasi at the University of Vienna, and Rosalind Hunter-Anderson, an independent researcher working in Albuqueque New Mexico.

"It's an unexpected gift to be able to learn about cultural patterns from genetic data," said David Reich, a professor in the Department of Human Evolutionary Biology and a professor of genetics at Harvard Medical School. "Today, traditional communities in the Pacific have both patrilocal and matrilocal population structures and there was a debate about what the common practice was in the ancestral populations. These results suggest that in the earliest seafarers, matrilocality was the rule.

The genetic analysis compared early seafarers from Guam, Vanuatu, and Tonga -- living about 2500 to 3,000 years ago -- revealing that their mitochondrial DNA sequences, which humans only inherit from their biological mother, differed almost completely while sharing much more of the rest of their DNA. The only way this can happen is if migrants who left their communities to marry into new ones were almost always males.

"Females certainly moved to new islands, but when they did so they were part of joint movements of both females and males" explains Reich. "This pattern of leaving the community must have been nearly unique to males in order to explain why genetic differentiation is so much higher in mitochondrial DNA than in the rest of the genome."

The new study from an interdisciplinary team of geneticists and archeologists quintuples the body of ancient DNA data from the vast Pacific region called Remote Oceania, the last habitable place on earth to be peopled. It also provides surprising insights into the extraordinarily complex peopling of one of Remote Oceania's major subregions.

Map of migration routes [Credit: David Reich, Yue-Chen Liu, and Rosalind Hunter-Anderson]

Humans arrived and spread through Australia, New Guinea, the Bismarck Archipelago, and the Solomon Islands beginning 50,000 years ago, but it wasn't until after 3,500 years ago that humans began living in Remote Oceania for the first time after developing the technology to cross open water in unique long-distance canoes.

This expansion included the region called Micronesia: about two thousand small islands north of the Equator including Guam, the Marshall Islands, the Caroline Islands, Palau, and the Northern Mariana Islands.

It's long been a mystery what the routes people took to arrive in the region. The revealing of five streams of migration into Micronesia helps bring clarity to this mystery and the origins of the people there today.

"These migrations we document with ancient DNA are the key events shaping this region's unique history," said Liu, a post-doctoral fellow in Reich's lab and the study's lead author. "Some of the findings were very surprising."

Of the five detected migrations, three were from East Asia, one from Polynesia, and a Papuan ancestry coming from the northern fringes of mainland New Guinea. The indigenous ancestry from New Guinea was a major surprise as a different stream of this migration -- one from New Britain, an island chain to the east of New Guinea -- was the source of the Papuan ancestry in the southwest Pacific and in Central Micronesia.

The researchers also found that present-day Indigenous people of the Mariana Islands in Micronesia, including Guam and Saipan, derive nearly all their pre-European-contact ancestry from two of the East Asian-associated migrations the researchers detected. It makes them the "only people of the open Pacific who lack ancestry from the New Guinea region," Liu said.

The researchers consulted with several Indigenous communities in Micronesia for the study. This is the fourth publication of original ancient DNA data from remote Pacific islands by Reich's group.

"It's important that when we do ancient DNA work, we don't just write a paper about the population history of a region and then move on," Reich said. "Each paper raises as many new questions as it answers, and this requires long term commitment to follow up the initial findings. In the Pacific islands there are so many open questions, so many surprises still to be discovered."

Author: Juan Siliezar | Source: Harvard University [July 06, 2022]

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Excavations at ancient Galilean synagogue uncover intricate mosaic floor panels dating back nearly 1,600 years

2022-07-05T18:00:00.063+03:00

A team of specialists and students led by University of North Carolina at Chapel Hill professor Jodi Magness recently returned to Israel’s Lower Galilee to continue unearthing nearly 1,600-year-old mosaics in an ancient Jewish synagogue at Huqoq. Discoveries made this year include the first known depiction of the biblical heroines Deborah and Jael as described in the book of Judges.

Israelite commander Barak depicted in the Huqoq synagogue mosaic
[Credit: Jim Haberman]

The Huqoq Excavation Project is now in its 10th season after recent seasons were paused due to the COVID-19 pandemic. Project director Magness, the Kenan Distinguished Professor of religious studies in Carolina’s College of Arts & Sciences, and assistant director Dennis Mizzi of the University of Malta focused this season on the southwest part of the synagogue, which was built in the late fourth-early fifth century C.E.

This season, the project team unearthed a part of the synagogue’s floor decorated with a large mosaic panel that is divided into three horizontal strips (called registers), which depicts an episode from the book of Judges chapter 4: The victory of the Israelite forces led by the prophetess and judge Deborah and the military commander Barak over the Canaanite army led by the general Sisera. The Bible relates that after the battle, Sisera took refuge in the tent of a Kenite woman named Jael (Yael), who killed him by driving a tent stake through his temple as he slept. The uppermost register of the newly-discovered Huqoq mosaic shows Deborah under a palm tree, gazing at Barak, who is equipped with a shield. Only a small part of the middle register is preserved, which appears to show Sisera seated. The lowest register depicts Sisera lying deceased on the ground, bleeding from the head as Jael hammers a tent stake through his temple.

Mosaic depicting a fox eating grapes in the ancient synagogue at Huqoq
[Credit: Jim Haberman]

“This is the first depiction of this episode and the first time we’ve seen a depiction of the biblical heroines Deborah and Jael in ancient Jewish art,” Magness said. “Looking at the book of Joshua chapter 19, we can see how the story might have had special resonance for the Jewish community at Huqoq, as it is described as taking place in the same geographical region – the territory of the tribes of Naphtali and Zebulon.”

Also among the newly discovered mosaics is a fragmentary Hebrew dedicatory inscription inside a wreath, flanked by panels measuring 6 feet tall and 2 feet wide, which show two vases that hold sprouting vines. The vines form medallions that frame four animals eating clusters of grapes: a hare, a fox, a leopard and a wild boar.

Mosaic depicting the construction of the Tower of Babel
[Credit: Jim Haberman]

A decade of discovery

Mosaics were first discovered at the site in 2012, and work continued each summer until the COVID-19 pandemic paused work after the dig in 2019. The mosaics exposed in the last 10 active seasons cover the synagogue’s aisles and main hall.

Discoveries along the east aisle include:

- Panels depicting Samson and the foxes (as related in Judges 15:4)

- Samson carrying the gate of Gaza on his shoulders (Judges 16:3)

- A Hebrew inscription surrounded by human figures, animals and mythological creatures including putti, or cupids

Mosaic depicting parting of the Red Sea
[Credit: Jim Haberman]

- The first non-biblical story ever found decorating an ancient synagogue — perhaps the legendary meeting between Alexander the Great and the Jewish high priest

The mosaic floor in the north aisle is divided into two rows of panels containing figures and objects accompanied by Hebrew inscriptions identifying them as biblical stories, including:

- One panel depicts two of the spies sent by Moses to explore Canaan carrying a pole with a cluster of grapes, labeled “a pole between two” (from Numbers 13:23)

- Another panel showing a man leading an animal on a rope is accompanied by the inscription “a small child shall lead them” (Isaiah 11:6)

Mosaic depicting the meeting between Alexander the Great and the Jewish high priest
[Credit: Jim Haberman]

The mosaics panels in the nave, or main hall, include:

- A portrayal of Noah’s Ark

- The parting of the Red Sea

- A Helios-zodiac cycle

- Jonah being swallowed by three successive fish

- The building of the Tower of Babel

Mosaic showing the "Month of Teveth (December-January) with the sign of Capricorn
from the Huqoq synagogue [Credit: Jim Haberman]

In 2019, the team uncovered panels in the north aisle that frame figures of animals identified by an Aramaic inscription as the four beasts representing four kingdoms in the book of Daniel, chapter 7. A large panel in the northwest aisle depicts Elim, the spot where the Israelites camped by 12 springs and 70 date palms after departing Egypt and wandering in the wilderness without water (Exodus 15:27).

In the 14th century C.E. (the Mamluk period), the synagogue was rebuilt and expanded in size, perhaps in connection with the rise of a tradition that the Tomb of Habakkuk was located nearby, which became a focal point of late medieval Jewish pilgrimage.

Mosaic showing Samson carrying the gate of Gaza on his shoulders
[Credit: Jim Haberman]

“The 14th century C.E. building appears to be the first Mamluk period synagogue ever discovered in Israel, making it no less important than the earlier building,” said Magness.

Sponsors of the project are UNC-Chapel Hill, Austin College, Baylor University, Brigham Young University and the University of Toronto. Students and staff from Carolina and the consortium schools participated in the dig. Financial support for the 2022 season was also provided by the National Geographic Society, the Loeb Classical Library Foundation, the Kenan Charitable Trust and the Carolina Center for Jewish Studies at UNC-Chapel Hill.

Mosaic showing the spies of Moses carrying clusters of grapes to explore Canaan
(OT, Numbers 13:23) [Credit: Jim Haberman]

The mosaics have been removed from the site for conservation, and the excavated areas have been backfilled. Excavations are scheduled to continue in summer 2023. For additional information and updates, visit the project’s website: www.huqoq.org.

Source: University of North Carolina at Chapel Hill [July 05, 2022]

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Greater overturning in the Pacific during the Ice Age

2022-07-05T14:00:00.025+03:00

Located between Australia and New Zealand, the Tasman Sea is an important but so far neglected component of the global ocean conveyor belt. Now a new study has discovered evidence that this marginal sea in the South Pacific also played an important role in the exchange of water masses between the large ocean basins during the last ice age. These findings will help to refine climate models and improve our understanding of ocean circulation and carbon storage in the sea, an international team of researchers led by geoscientist Dr Torben Struve from the University of Oldenburg reports in the journal Nature Communications.

Some fossil specimens of the hard coral Desmophyllum dianthus
[Credit: Eleni Anagnostou]

In their study the researchers examined 62 fossil specimens of the stony coral Desmophyllum dianthus. These were collected by the underwater remotely operated vehicle JASON during a research expedition south of Tasmania at depths between 1,400 and 1,700 metres. According to dating analysis, these animals lived about 10,000 to 70,000 years ago, a period that included the peak and end of the last glacial period. "The corals grow in areas with strong currents and turbulence that inhibit the deposition of sediment," explained Struve, who conducts research in the Marine Isotope Geochemistry group at the University of Oldenburg's Institute for Chemistry and Biology of the Marine Environment.

Because the skeletons of these sedentary animals record the chemical fingerprint of the surrounding seawater, complex analyses can reveal the chemical composition of the ocean at the corresponding water depth during the corals' lifetime. This in turn provided clues about which water masses flowed through the Tasman Sea at the time. "These cold-water corals are a particularly good archive for studying the chemical composition of deep ocean currents in the past," Struve explained.

Young water flowed through the depths of the Tasman Sea

In their study the researchers focused specifically on the ratio of different variants of the trace element neodymium, some of which are produced by radioactive decay and are commonly referred to as radiogenic isotopes. The analysis showed that water from the Pacific Ocean flowed through the depths of the Tasman Sea around the peak of the ice age -- as indicated by the relatively high content of radiogenic neodymium in the coral samples.

The underwater robot JASON in action [Credit: Eleni Anagnostou]

The investigations also showed that this water from the Pacific had been in contact with the sea surface relatively recently compared to other water masses in the same depth range, or in other words, that it had been relatively "young." As the team writes in their paper, the data supports a scenario in which the upper Pacific Ocean was more mixed during the last ice age than it is today -- while at the same time the deepest layers were more isolated from the atmosphere, which contributed to the long-term storage of carbon dioxide and the cooler glacial climate.

According to the new study, the circulation patterns during the last glacial period would have looked like this: in the North Pacific, surface water sank to a depth of about 2,000 metres and then spread a long way southward. After flowing around the southern tip of the Australian island of Tasmania, this water could have flowed into the Indian Ocean where it joined the global "conveyor belt" of ocean currents and reinforced it. This conveyor belt plays an important role in distributing heat among the various ocean basins: the warm North Atlantic Current, for example, is responsible for the comparatively mild climate in northwestern Europe. From the North Atlantic, the circulation extends across the Antarctic Circumpolar Current and the Indian Ocean to the northern Pacific -- and then back again. In today's system, the water in the North Pacific is the oldest, meaning that the last contact with the surface occurred a very long time ago.

The historical view allocated the return flow of this conveyor belt to the Indian Ocean mainly to a relatively shallow strait north of Australia. However, recent studies suggest that the outflow of Pacific waters through the Tasman Sea is also significantly involved in the exchange of water masses between ocean basins -- albeit at shallower depths than during the last glacial interval. It is possible that up to half of the water flowing northwards within the global conveyor belt in the Atlantic today originated in the area south of Australia. "Our study contributes to a better understanding of the dynamics of this global ocean circulation system under changing climatic conditions," said Struve. Now there is evidence that there was a close link between changes in the deep Tasman outflow and circulation changes in the Pacific Ocean during the last glacial period.

Source: University of Oldenburg [July 05, 2022]

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