Britain's history "could be wrecked" by Stonehenge tunnel, say archaeologists who found prehistoric frog legs
Archaeologists from The Hebrew University of Jerusalem’s Institute of Archaeology have discovered a monumental entryway to the Herodian Hilltop Palace at the Herodium National Park. The unique complex was uncovered during excavations by The Herodium Expedition in Memory of Ehud Netzer over the past year, as part of a project to develop the site for tourism.
The main feature of the entryway is an impressive corridor with a complex system of arches spanning its width on three separate levels. These arches buttressed the corridor’s massive side-walls, allowing the King and his entourage direct passage into the Palace Courtyard. Thanks to the supporting arches, the 20-meter long and 6-meter wide corridor has been preserved to a height of 20 meters.
The Hebrew University archaeologists — Roi Porat, Yakov Kalman and Rachel Chachy — suggest that the corridor was built as part of Herod’s plan to turn Herodium into a massive artificial volcano-shaped hill, a vast and impressive monument designed to commemorate the architect-King.
Surprisingly, during the course of the excavations, it became evident that the arched corridor was never actually in use, as prior to its completion it became redundant. This appears to have happened when Herod, aware of his impending death, decided to convert the whole hilltop complex into a massive memorial mound, a royal burial monument on an epic scale.
Whatever the case, the corridor was back-filled during the construction of the massive artificial hill at the end of Herod’s reign. The upper section of a new monumental stairway stretching from the hill’s base to its peak, constructed during the course of this building phase, appears to have been built over it.
The excavators point out that not only was the arched corridor covered over in the course of the construction of the hill-monument, but also all the structures earlier built by Herod on the hill’s slopes, including the Royal Theater uncovered by the expedition in 2008, while still led by Prof. Ehud Netzer, since deceased.
The only edifice not covered over was the splendid mausoleum-style structure, identified by Netzer and the expedition as Herod’s burial-place. Together with the monumental cone-shaped hill, this constituted the unique Herodian Royal burial-complex.
During the course of the current excavations, the original impressive Palace vestibule, blocked when the corridor became redundant, was also exposed. This entry-room, decorated with splendid painted frescoes, had a magnificent entryway leading into it, and offered evidence of the rebel occupation during the Great Revolt (66-71 CE), including Jewish Revolt coinage and crude temporary structures.
In addition, the excavations in the arched corridor also turned up impressive evidence from the Bar Kokhba Revolt period (132-135/6 CE): hidden tunnels dug on the site by the rebels as part of the guerilla warfare they waged against the Romans. Supported in part by wooden beams, these tunnels exited from the hilltop fortress by way of the corridor’s walls, through openings hidden in the corridor. One of the tunnels revealed a well-preserved construction of 20 or so cypress-wood branches, arranged in a cross-weave pattern to support the tunnel’s roof.
In the future, according to Mr. Shaul Goldstein, Director of Israel’s Nature and Parks Authority, the excavation of the arched corridor will allow visitors direct access to the Herodium hilltop palace-fortress, in the same way that Herod entered it two thousand years ago. There are also plans to provide tourists direct access from the structures on the slope, the Royal Theater and the Mausoleum, via the earlier monumental stairway, to the hilltop Palace.
Hebrew University of Jerusalem – Header Image – Aerial view of Herodium complex where Hebrew University archaeologists unearthed a unique palace entry complex. (Credit: Tatzpit Aerial Photography)
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Findings suggest that bacteria involved in the decay of those organisms play an active role in how fossils are formed—often in a matter of just a few tens to hundreds of years. Understanding the relationship between decay and fossilization will inform future study and help researchers interpret fossils in a new way.
“The vast majority of the fossil record is composed of bones and shells,” said James Schiffbauer, assistant professor of geological sciences in the College of Arts and Science at MU. “Fossils of soft-bodied animals like worms and jellyfish, however, provide our only views onto the early evolution of animal life. Most hypotheses as to the preservation of these soft tissues focus on passive processes, where normal decay is halted or impeded in some way, such as by sealing off the sediments where the animal is buried. Our team is instead detailing a scenario where the actual decay helped ‘feed’ the process turning the organisms into fossils—in this case, the decay of the organisms played an active role in creating fossils.”
Schiffbauer studied a type of fossil animal from the Ediacaran Period called Conotubus, which lived more than 540 million years ago. He noted that these fossils are either replicated by, or associated with, pyrite—commonly called fool’s gold. The tiny fossils are tube-shaped and believed to have been composed of substances similar at least in hardness to human fingernails. These fossilized tubes are all that remain of the soft-bodied animals that inhabited them and most likely resembled worms or sea anemone-like animals.
“Most of the animals that had once lived on the Earth—with estimates eclipsing 10 billion species—were never preserved in the fossil record, but in our study we have a spectacular view of a tinier fraction of soft-bodied animals,” said Shuhai Xiao, professor of geobiology at Virginia Tech and a co-author on this study. “We asked the important questions of how, and under what special conditions, these soft-tissued organisms can escape the fate of complete degradation and be preserved in the rock record.”
Schiffbauer and his team performed a sophisticated suite of chemical analyses of these fossils to determine what caused the pyrite to form. They found that the fool’s gold on the organisms’ outer tube formed when bacteria first began consuming the animal’s soft tissues, with the decay actually promoting the formation of pyrite.
“Normally, the earth is good at cleaning up after itself,” Schiffbauer said. “In this case, the bacteria that helped break down these organisms also are responsible for preserving them as fossils. As the decay occurred, pyrite began replacing and filling in space within the animal’s exoskeleton, preserving them. Additionally, we found that this process happened in the space of a few years, perhaps even as low as 12 to 800. Ultimately, these new findings will help scientists to gain a better grasp of why these fossils are preserved, and what features represent the fossilization process versus original biology, so we can better reconstruct the evolutionary tree of life.”
Schiffbauer’s study, “A unifying model for Neoproterozoic-Palaeozoic exceptional fossil preservation through pyritization and carbonaceous compression,” was published in the journal Nature Communications. He collaborated with Shuhai Xiao and Jerry Hunter of Virginia Tech, Yaoping Cai and Hong Hua on Northwest University, Xi’an, China, Adam Wallace of the University of Delaware, Huifang Xu at the University of Wisconsin, Yongbo Peng of Indiana University and Alan Kaufman of the University of Maryland. Schiffbauer is the corresponding author.
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The Great Sphinx of Giza is a limestone statue of a reclining or couchant sphinx (a mythical creature with a lion’s body and a human head) that stands on the Giza Plateau on the west bank of the Nile in Giza, Egypt. The face of the Sphinx is generally believed to represent the face of the Pharaoh Khafra.
It is the largest monolith statue in the world, standing 73.5 metres (241 ft) long, 19.3 metres (63 ft) wide, and 20.22 m (66.34 ft) high. It is the oldest known monumental sculpture, and is commonly believed to have been built by ancient Egyptians of the Old Kingdom during the reign of the Pharaoh Khafra (c. 2558–2532 BC).
El Castillo, Chichen Itza – 1892
El Castillo, also known as the Temple of Kukulcan, is a Mesoamerican step-pyramid that dominates the center of the Chichen Itza archaeological site in the Mexican state of Yucatán.
Built by the pre-Columbian Maya civilization sometime between the 9th and 12th centuries CE, El Castillo served as a temple to the god Kukulkan, the Yucatec Maya Feathered Serpent deity closely related to the god Quetzalcoatl known to the Aztecs and other central Mexican cultures of the Postclassic period.
The Washington Monument – 1862
The Washington Monument is an obelisk on the National Mall in Washington, DC, built to commemorate George Washington, once commander-in-chief of the early Continental Army and the first American president.
The monument, made of marble, granite, and bluestone gneiss, standing 555 feet 5 1⁄8 inches (169.294 m) tall. Construction of the monument began in 1848, was halted from 1854 to 1877, and was finally completed in 1884.
Edfu – 1831
The Temple of Edfu is an ancient Egyptian temple located on the west bank of the Nile in the city of Edfu which was known in Greco-Roman times as Apollonopolis Magna, after the chief god Horus-Apollo. It is one of the best preserved temples in Egypt. The temple, dedicated to the falcon god Horus, was built in the Ptolemaic period between 237 and 57 BC.
Macchu Picchu – 1912
Machu Picchu is a 15th-century Inca site located 2,430 metres (7,970 ft) above sea level. It is located in the Cusco Region, Urubamba Province, Machupicchu District in Peru. It is situated on a mountain ridge above the Sacred Valley which is 80 kilometres (50 mi) northwest of Cusco and through which the Urubamba River flows.
Colosseum – 1922
The Colosseum or Coliseum, also known as the Flavian Amphitheatre is an elliptical amphitheatre in the centre of the city of Rome, Italy. Built of concrete and stone, it was the largest amphitheatre of the Roman Empire, and is considered one of the greatest works of Roman architecture and engineering. It is the largest amphitheatre in the world.
The Colosseum is situated just east of the Roman Forum. Construction began under the emperor Vespasian in 70 AD, and was completed in 80 AD under his successor and heir Titus.
Eiffel Tower – 1888
The Eiffel Tower is an iron lattice tower located on the Champ de Mars in Paris. It was named after the engineer Gustave Eiffel, whose company designed and built the tower. Erected in 1889 as the entrance arch to the 1889 World’s Fair, it was initially criticised by some of France’s leading artists and intellectuals for its design, but has become both a global cultural icon of France and one of the most recognisable structures in the world.
Abu Simbel – 1926
The Abu Simbel temples are two massive rock temples in Abu Simbel, southern Egypt, near the border with Sudan. They are situated on the western bank of Lake Nasser, about 230 km southwest of Aswan (about 300 km by road). The twin temples were originally carved out of the mountainside during the reign of Pharaoh Ramesses II in the 13th century BC, as a lasting monument to himself and his queen Nefertari to commemorate his alleged victory at the Battle of Kadesh. However, the complex was relocated in its entirety in 1968, on an artificial hill made from a domed structure, high above the Aswan High Dam reservoir.Mesa Verde – 1891
Mesa Verde National Park is a U.S. National Park and UNESCO World Heritage Site located in Montezuma County, Colorado, United States. The Anasazi inhabited Mesa Verde between 600 to 1300, though there is evidence they left before the start of the 15th century. They were mainly subsistence farmers, growing crops on nearby mesas. By the year 750 the people were building mesa-top villages made of adobe. In the late 1190s they began to build the cliff dwellings for which Mesa Verde is famous.
Acropolis of Athens – 1872
The Acropolis of Athens is an ancient citadel located on a high rocky outcrop above the city of Athens and contains the remains of several ancient buildings of great architectural and historic significance, the most famous being the Parthenon.
While there is evidence that the hill was inhabited as far back as the fourth millennium BC, it was Pericles (c. 495 – 429 BC) in the fifth century BC who coordinated the construction of the site’s most important buildings including the Parthenon, the Propylaia, the Erechtheion and the temple of Athena Nike.
Contributing Source : WikiPedia
Scientists have puzzled over this chronology as mastodons, which looked similar to modern-day Asian elephants, are known to have had a preference for forests and wetlands filled with heaps of leafy goods. In a paper published today in the Proceedings of the National Academy of Sciences, an international team suggests that the Arctic and Subarctic were just temporary “holiday homes” for mastodons when the local climate was warm around 125,000 years ago.
When the cold weather returned, their populations moved much further to the south, where the paper suggests they ultimately died out about 10,000 years ago. The findings debunk theories about over hunting by early humans being the reason for their disappearance from this region as these new dates show they were wiped out locally before human colonisation.
Researchers from the University of Oxford and the University of California radiocarbon dated collagen from 36 fossil teeth and bones of American mastodons from Alaska and Yukon. The dates for all of the fossils were older than previously thought. Alaska and Yukon were part of an ancient region known as eastern Beringia which is thought to have connected Asia with North America at various times. When taking mastodon habitat preferences and other ecological and geological information into account, the results show that mastodons probably only lived in eastern Beringia for a relatively short time when temperatures were as warm as they are today.
Dr Fiona Brock, a researcher from the Oxford Radiocarbon Accelerator Unit at the University of Oxford, said: ‘We applied dating techniques to target the collagen, avoiding contaminants such as varnish and glues, applied several years ago to strengthen the specimens, which otherwise may make the dates “younger” than they should be. Our state of the art techniques developed at Oxford to isolate and date individual amino acids from the bones have resulted in new dating evidence that provides a big shift in our thinking. The American mastodons weren’t suddenly wiped out by the humans but moved south where their population dwindled away.’
Lead author Grant Zazula, a palaeontologist from the Yukon Government, said: ‘The residency of mastodons in the north did not last long. The return to cold, dry glacial conditions along with the advance of continental glaciers around 75,000 years ago effectively wiped out their habitats. This new evidence suggests that mastodons disappeared from Beringia, and their populations became displaced to areas much further to the south, where they ultimately suffered complete extinction about 10,000 years ago.’
Over the course of the late Pleistocene (between about 10,000 and 125,000 years ago), the American mastodon (Mammut americanum) species was widespread. They lived in many parts of continental North America, as well as the tropics of Honduras and the Arctic coast of Alaska. Scholars had presumed that the mass extinction of mastodons was the result of rapid climate change in North America or that they were over hunted. However, the new findings show they died out several tens of millennia before the onset of climate changes at the end of the Ice Age 10,000 years ago. Researchers know that giant ground sloths, American camels, and giant beavers made the migration south as well, but they are still investigating what other groups of animals might have done this.
But while aqueducts, sewers and baths retain an obvious presence in the landscape and in the archaeological record, the Romans’ largest and most important water achievement may have been “virtual”.
The Romans developed networks of trade and food supply that enabled them to escape local water constraints, in a way that is explained in a new study in the journal Hydrology and Earth System Sciences. Fertile regions such as southern Spain or Italy’s Po valley would grow lots of food and ship it back to Rome or to the drier outposts of the Empire.
Embedded within this is a what geographers call a virtual water trade – an indirect way of shifting this precious resource from wetter, less populated areas to those regions with more people or a less consistent climate.
The map below shows this in action. The amount of virtual water imports (a) and exports (b) in different parts of the Empire are illustrated by the size of the circles. The numbers express this in tonnes of grain. Rome is by far the largest water importer, followed by Alexandria and Memphis in Egypt, and Ephesus and Antioch in modern-day Turkey. Spain and Egypt were the biggest exporters.
All ships lead to Rome
The paper’s primary author, Brian Dermody at the University of Utrecht, suggests this sophisticated water economy ultimately contributed to its own downfall as it enabled urban populations to boom beyond sustainable levels.
Does this sound uncomfortably familiar? In the next 30 years we are facing a critical combination of inter-related stresses on the core resources that keep our civilisation running. As it happens, the Romans gave us a word for that too – the “food-water-energy nexus” (from the Latin nectere, to bind together).
So are we doomed to the same fate as the Romans?Increased energy use
As its name suggests, the nexus recognises that different resources are intimately interconnected. We need water for drinking, washing and for industry; but we also need it to grow food, and around 70% of global fresh water supply is used for farming. As populations grow and become more wealthy, demand for food will increase, placing pressure on domestic water supply and industrial output.
Economic growth and technological developments increase energy use, driving additional demand for water in power station cooling and other uses in energy generation. The rise in shale gas extraction provides a stark illustration of this: irrespective of the many other ethical and political issues surrounding fracking, it is its thirst for water (used to force the hydrocarbons out of the rocks) that may prove the key limitation. After all, 38% of the world’s shale gas resources are located in areas of extremely high water stress or arid conditions. In the UK, plans for fracking in major regions such as the Severn catchment could place untenable pressure on water use for farming and domestic supply.
In all this complexity, the mega-issue of climate change arguably plays only an aggravating role. Intensive farming is degrading soil, its primary resource base, up to 100 times faster than the rates at which it is formed. Non-renewable fuel and mineral resources are becoming increasingly scarce and more costly to recover. And renewable, drinkable water supplies are under often extreme threat.
Solving climate change will not in itself solve the problems of the food-water-energy nexus; in fact it should be apparent that our effective response to climate change is deeply entwined with a sustainable untangling of the nexus.Interconnected threats
Like the Romans, the “modern” response to the emergent limitations of the food-water-energy nexus was economic. Global trade through the 20th century allowed us to circumvent local or regional resource limitations, stimulating unprecedented population growth along with rising wealth and living standards.
Many countries could not hope to maintain their current consumption of food and resources if they were forced become self-reliant on resources available within their territory – in the current economic and technological conditions, at least.
This makes the global economy vulnerable to regional problems. Look at this year’s escalation of tension between Russia and the West, for instance. Sanctions imposed by both sides have affected international trade in wheat and other crops, leading to supply shortages or gluts in some places and the destabilisation of farming economies and farmer incomes in others – and has raised the threat of disruption to transnational energy supplies. Again, the challenges of the nexus – and our vulnerability to those changes – transcend the background threat of climate change.
So, faced with challenges which appear strikingly similar, what can our postmodern, self-aware civilisation do to avoid the fate of the Romans? We cannot stop the nexus any more than we can prevent the climate change that will result from our current levels of greenhouse gas emission. Business as usual is clearly not an option. In the absence of a magic bullet (or something much worse, an environmental disaster or collapse), resilience is the key.
One advantage we have over the Romans is information; we can learn from precedent. We can see what is over the horizon and make a judgement on how it may impact our lives and livelihoods. The challenge, unfortunately, remains how to stimulate people and politicians to change in response to those dangers. However human nature means we are as ready to listen to soothsayers as scientists and, in that respect, we and the Romans are still very much the same.Written by Jonathan Bridge
Lecturer in Environmental Engineering at University of Liverpool
The Conversation – Header Image : WikiPedia
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According to Amit Shadman, excavation director on behalf of the Israel Antiquities Authority, “The farm, which is extraordinarily well-preserved, extends across an area of 30 × 40 m and was built in the eighth century BCE, the time of the Assyrian conquest.
Farm houses during this period served as small settlements of sorts whose inhabitants participated in processing agricultural produce. The numerous wine presses discovered in the vicinity of the settlement indicate the wine industry was the most important branch of agriculture in the region. A large silo, which was used to store grain, shows that the ancient residents were also engaged in growing cereal.”
According to Shadman the building continued to be used during the Persian period (also known as the Time of the Return to Zion) in the sixth century BCE, and in the Hellenistic period as well which began in the country with the arrival of Alexander the Great, one of the greatest military leaders of antiquity. With Alexander’s victory over the Persian army in 333 BCE he embarked upon numerous successful military campaigns. His campaign in Israel did not encounter any special difficulties and the country opened its gates to the great warrior.
Evidence of a Greek presence in the region was uncovered on one of the floors of the building in the form of a rare silver coin bearing the military leader’s name – ΑΛΕΞΑNΔΡΟΥ. One can also discern the image of the god Zeus on that side of the coin, while the head of Heracles appears on its reverse.
During the Ottoman period a lime kiln was dug into the structure which utilized the stones in the building as ready source of raw material.
In light of this impressive building’s excellent state of preservation, the Israel Antiquities Authority and Ministry of Construction decided to conserve the structure in situ for the benefit of the city’s residents and the visiting public.
Israel Antiquities Authority – Header Image – An aerial photograph of the farm house. Photographic credit: Skyview Company, courtesy of the Israel Antiquities Authority
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In what MAI Director James Adovasio, Ph.D., describes as the most extensive Paleoindian excavation currently under way in all of North America, that being the Old Vero Man site where Sellards drew his now century-old conclusions, evidence uncovered recently by MAI positively demonstrates the contemporaneous presence of humans and late Pleistocene animals.
The MAI began its Vero excavation last year at the invitation of the Old Vero Ice Age Sites Committee (OVIASC), a dedicated group of citizens determined to define Vero’s rightful place in the archaeological record. OVIASC has been instrumental in raising the funds necessary for the first season of excavation that ran January to May 2014, and will commence again in January 2015.
Although actual human remains were not retrieved in the dig’s first round, certain artifacts identified during the excavation, among them burned fragments of bone, some with cut marks; could only be the work of human beings, Adovasio said.
“It’s taken more than 100 years, but we now know that Sellards was right,” he added, crediting rigorous excavation protocols and new technology that enabled investigators to proceed with a precise understanding of the site’s geology – an advantage Sellards did not have.
Further, radiocarbon dating of the soil where much of the cultural materials have been found – in all, 170 species of plants and animals from MAI and earlier investigations – goes back 13,000-14,000 calendar years, making Vero the oldest terrestrial archaeological site in all of Florida and one of the oldest in the entire Southeast U.S.
Adovasio said MAI archaeologists and students also uncovered a buried soil layer dating back some 19,000 years, and that is where they intend to concentrate their second excavation in January.
“If that stratum or layer produces cultural materials, it will be one of the oldest locations in all of North or South America,” Adovasio added.
While the current findings are significant to Floridians, Adovasio said the Vero site also plays a role in the more far-reaching debate surrounding the founding populations of the Americas. Historically, the first agreed-upon culture in the Americas was called Clovis, after a site discovered in New Mexico in the 1920s. Sites identified as Clovis dated around 11,200 – 11,500 radiocarbon years ago. But, beginning in the 1970s, sites predating Clovis began to be discovered, such as Pennsylvania’s Meadowcroft Rockshelter, where Adovasio was principal excavator; Monte Verde in Chile and Gault in Central Texas.
Those discoveries – and now Vero – go a long way toward proving Clovis believers wrong and turning most archaeologists on Adovasio’s side of the debate.
Moving forward, Adovasio said that subsequent investigations are expected to reveal the interrelationship of human, animal and plant populations at Vero. He said their hope is “to distinguish lifestyles of the folks who might have lived at Vero in terms of how much they match or don’t match other behavioral models from other sites.”
Adovasio and his colleagues (C. Andrew Hemmings, A.E. Marjenin, F.J. Vento and A. Vega) made their first presentation on the Vero excavation last month at the 71st Annual Southeastern Archaeological Conference in Greenville, South Carolina. Their symposium presentation was titled “The Old Vero Man Site: Current Investigations Suggest Pleistocene Human Occupation.”
The faunal and floral materials recovered, among them a bone tentatively identified as that of a dire wolf, now extinct, are being studied in the archaeology labs at Mercyhurst University, creating a rare and historic opportunity for students.
MAI is now working with Florida Atlantic University scientists, who intend to analyze ancient DNA found at the dig site to provide yet another glimpse of the Florida landscape at the end of the last Ice Age.
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The absence of teeth or “edentulism” has evolved on multiple occasions within vertebrates including birds, turtles, and a few groups of mammals such as anteaters, baleen whales and pangolins. Where early birds are concerned, the fossil record is fragmentary. A question that has intrigued biologists is: Based on this fossil record, were teeth lost in the common ancestor of all living birds or convergently in two or more independent lineages of birds?
A research team led by biologists at the University of California, Riverside and Montclair State University, NJ, has found an answer. Using the degraded remnants of tooth genes in birds to determine when birds lost their teeth, the team reports in the Dec. 12 issue of Science that teeth were lost in the common ancestor of all living birds more than 100 million years ago.
“One of the larger lessons of our finding is that ‘dead genes,’ like the remnants of dead organisms that are preserved in the fossil record, have a story to tell,” said Mark Springer, a professor of biology and one of the lead authors of the study along with Robert Meredith at Montclair State University who was previously a graduate student and postdoctoral researcher in Springer’s laboratory. “DNA from the crypt is a powerful tool for unlocking secrets of evolutionary history.”
Springer explained that edentulism and the presence of a horny beak are hallmark features of modern birds.
“Ever since the discovery of the fossil bird Archaeopteryx in 1861, it has been clear that living birds are descended from toothed ancestors,” he said. “However, the history of tooth loss in the ancestry of modern birds has remained elusive for more than 150 years.”
All toothless/enamelless vertebrates are descended from an ancestor with enamel-capped teeth. In the case of birds, it is theropod dinosaurs. Modern birds use a horny beak instead of teeth, and part of their digestive tract to grind up and process food.
Tooth formation in vertebrates is a complicated process that involves many different genes. Of these genes, six are essential for the proper formation of dentin (DSPP) and enamel (AMTN, AMBN, ENAM, AMELX, MMP20).
The researchers examined these six genes in the genomes of 48 bird species, which represent nearly all living bird orders, for the presence of inactivating mutations that are shared by all 48 birds. The presence of such shared mutations in dentin and enamel-related genes would suggest a single loss of mineralized teeth in the common ancestor of all living birds.
Springer, Meredith, and other members of their team found that the 48 bird species share inactivating mutations in both dentin-related (DSPP) and enamel-related genes (ENAM, AMELX, AMTN, MMP20), indicating that the genetic machinery necessary for tooth formation was lost in the common ancestor of all modern birds.
“The presence of several inactivating mutations that are shared by all 48 bird species suggests that the outer enamel covering of teeth was lost around ~116 million years ago,” Springer said.
On the basis of fossil and molecular evidence, the researchers propose a two-step scenario whereby tooth loss and beak development evolved together in the common ancestor of all modern birds. In the first stage, tooth loss and partial beak development began on the anterior portion of both the upper and lower jaws. The second stage involved concurrent progression of tooth loss and beak development from the anterior portion of both jaws to the back of the rostrum.
“We propose that this progression ultimately resulted in a complete horny beak that effectively replaced the teeth and may have contributed to the diversification of living birds,” Springer said.
The research team also examined the genomes of additional toothless/enamelless vertebrates including three turtles and four mammals (pangolin, aardvark, sloth, and armadillo) for inactivating mutations in the dentin- and enamel-related genes. For comparison, the researchers looked at the genomes of mammalian taxa with enamel-capped teeth.
“All edentulous vertebrate genomes that we examined are characterized by inactivating mutations in DSPP, AMBN, AMELX, AMTN, ENAM, and MMP20, rendering these genes non-functional,” Springer said. “The dentin-related gene DSPP is functional in vertebrates with enamelless teeth – sloth, aardvark, armadillo. All six genes are functional in the American alligator, a representative of Crocodylia, the closest living relatives of birds, and mammalian taxa with enamel capped teeth.”
The research was supported, in part, by a grant to Springer from the National Science Foundation.
Springer and Meredith were joined in the research by Guojie Zhang at China National GeneBank, China; M. Thomas P. Gilbert at the University of Copenhagen Oster Voldgade, Denmark; and Erich D. Jarvis at Duke University Medical Center, NC.
All the scientists are coauthors with several others, including UC Riverside biologist John Gatesy, on a second paper in the same issue of Science. This paper employs the same 48 bird genomes to ask the question: “What makes a bird a bird?”
“The new bird genomes represent a major advance given that only a handful of bird genomes – zebra finch, turkey, chicken and duck – were previously available,” Springer said.
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