The Great London [Search results for Fossils

  • Fossils: Dinosaur fossil investigation unlocks possible soft tissue treasure trove

    Fossils: Dinosaur fossil investigation unlocks possible soft tissue treasure trove

    Scientists have found remnants that have some similarities to red blood cells and collagen fibres in fragments of dinosaur fossils.

    Dinosaur fossil investigation unlocks possible soft tissue treasure trove
    A zoom-in of potential red blood cells inside a fossil fragment that has been sliced 
    open with a focused ion beam [Credit: Imperial College London]

    The team from Imperial College London have detected what look like soft tissue remnants in the fragments of 75 million year old dinosaur fossils even though the fossils are poorly preserved. Scientists have previously only found soft tissue in dinosaur fossils that have been exceptionally well preserved, which are very rare and far fewer in number.

    The researchers suggest their study, published today in Nature Communications, may cause palaeontologists to rethink how fossils are preserved, and may be the first step towards a better understanding of the biology of dinosaurs and the relationships between different species.

    In the study, the team analysed eight fossil fragments that have for more than a century been in the Natural History Museum's Sternberg and Cutler collections.

    The researchers examined part of a fossilised dinosaur claw and identified tiny structures that look ovoid and with an inner denser core. These could potentially be red blood cells although the researchers caution that further evidence would be needed to confirm that the structures do not have another origin. The hope is that if red blood cells can be found in fossilised dinosaur fragments, this could help scientists to understand when dinosaurs evolved a warm blooded, bird-like metabolism.

    In one dinosaur fossil fragment, the team also found structures that looked fibrous and had a banded structure similar to the banding that can be seen in modern day collagen fibres. The structure of collagen varies between different animal groups, providing a type of fingerprint to link related creatures. Further evidence would be needed to definitively conclude that the structures found originate from a preservation of collagen. If verified, the identification of collagen-like structures could in the future provide a new independent line of evidence to show how various dinosaur groups are related to each other.

    Study author Dr Sergio Bertazzo, a Junior Research Fellow from the Department of Materials at Imperial College London, said: "We still need to do more research to confirm what it is that we are imaging in these dinosaur bone fragments, but the ancient tissue structures we have analysed have some similarities to red blood cells and collagen fibres. If we can confirm that our initial observations are correct, then this could yield fresh insights into how these creatures once lived and evolved."

    Study author Dr Susannah Maidment, a Junior Research Fellow from the Department of Earth Science and Engineering at Imperial College London, added: "Our study is helping us to see that preserved soft tissue may be more widespread in dinosaur fossils than we originally thought. Although remnants of soft tissues have previously been discovered in rare, exceptionally preserved fossils, what is particularly exciting about our study is that we have discovered structures reminiscent of blood cells and collagen fibres in scrappy, poorly preserved fossils. This suggests that this sort of soft tissue preservation might be widespread in fossils. Early indications suggest that these poorly preserved fossils may be useful pieces in the dinosaur jigsaw puzzle to help us to understand in more detail how dinosaurs evolved into being warm blooded creatures, and how different dinosaur species were related."

    To carry out their study the team used a range of techniques. The first involved the use of a scanning electron microscopy device to observe the structure, composition and location of the soft tissue inside the dinosaur fossil fragments. The team then used a focused ion beam to slice into the samples and observe the internal structure of the fossils. They also examined the fossils using a transmission electron microscope to detect the fibrous structures.

    Birds are the distant relatives of dinosaurs, so the researchers used an ion mass spectrometer device to compare their ancient soft tissue to a blood sample taken from an Emu. This enabled them to compare and contrast the samples and see that their fossils had some similarities in the organic signatures to the blood cells present in the emu blood sample.

    The next step will see the team carrying out more research to confirm that the structures that they've observed are found in a wider range of fossil samples and also to understand how widespread this sort of soft tissue preservation might be in dinosaur fossils, how far back this type of preservation could go in the fossil records and the reasons why it may have occurred.

    Author: Colin Smith | Source: Imperial College London [June 10, 2015]

  • Fossils: Oldest pine fossils reveal fiery past

    Fossils: Oldest pine fossils reveal fiery past

    Scientists have found the oldest fossils of the familiar pine tree that dominates Northern Hemisphere forests today.

    Oldest pine fossils reveal fiery past
    False-colour image of the fossil 
    [Credit: H. Falcon-Lang]

    Scientists from the Department of Earth Sciences at Royal Holloway, University of London have found the oldest fossils of the familiar pine tree that dominates Northern Hemisphere forests today.

    The 140-million-year-old fossils (dating from the Cretaceous 'Age of the Dinosaurs') are exquisitely preserved as charcoal, the result of burning in wildfires. The fossils suggest that pines co-evolved with fire at a time when oxygen levels in the atmosphere were much higher and forests were especially flammable.

    Dr Howard Falcon-Lang from Royal Holloway, University of London) discovered the fossils in Nova Scotia, Canada. He said: "Pines are well adapted to fire today. The fossils show that wildfires raged through the earliest pine forests and probably shaped the evolution of this important tree." Modern pines store flammable resin-rich deadwood on the tree making them prone to lethal fires. However, they also produce huge numbers of cones that will only germinate after a fire, ensuring a new cohort of trees is seeded after the fire has passed by."

    The research is published in the journal Geological Society of America.

    Source: University of Royal Holloway London [March 10, 2016]

  • Human Evolution: DNA from Neanderthal relative may shake up human family tree

    Human Evolution: DNA from Neanderthal relative may shake up human family tree

    In a remarkable technical feat, researchers have sequenced DNA from fossils in Spain that are about 300,000 to 400,000 years old and have found an ancestor—or close relative—of Neanderthals. The nuclear DNA, which is the oldest ever sequenced from a member of the human family, may push back the date for the origins of the distinct ancestors of Neanderthals and modern humans, according to a presentation here yesterday at the fifth annual meeting of the European Society for the study of human evolution.

    DNA from Neanderthal relative may shake up human family tree
    DNA from these fossilized bones and teeth in a Spanish cave are providing
     clues about the origins of Neanderthals and modern humans 
    [Credit: J.-J. Hublin; Royal Museum For Central Africa,
     Tervuren, Belgium]

    Ever since researchers first discovered thousands of bones and teeth from 28 individuals in the mid-1990s from Sima de los Huesos (“pit of bones”), a cave in the Atapuerca Mountains of Spain, they had noted that the fossils looked a lot like primitive Neanderthals. The Sima people, who lived before Neanderthals, were thought to have emerged in Europe. Yet their teeth, jaws, and large nasal cavities were among the traits that closely resembled those of Neanderthals, according to a team led by paleontologist Juan-Luis Arsuaga of the Complutense University of Madrid. As a result, his team classified the fossils as members of Homo heidelbergensis, a species that lived about 600,000 to 250,000 years ago in Europe, Africa, and Asia. Many researchers have thought H. heidelbergensis gave rise to Neanderthals and perhaps also to our species, H. sapiens, in the past 400,000 years or so.

    But in 2013, the Sima fossils’ identity suddenly became complicated when a study of the maternally inherited mitochondrial DNA (mtDNA) from one of the bones revealed that it did not resemble that of a Neanderthal. Instead, it more closely matched the mtDNA of a Denisovan, an elusive type of extinct human discovered when its DNA was sequenced from a finger bone from Denisova Cave in Siberia. That finding was puzzling, prompting researchers to speculate that perhaps the Sima fossils had interbred with very early Denisovans or that the “Denisovan” mtDNA was the signature of an even more ancient hominin lineage, such as H. erectus. At the time, researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who had obtained the mtDNA announced that they would try to sequence the nuclear DNA of the fossils to solve the mystery.

    After 2 years of intense effort, paleogeneticist Matthias Meyer of the Max Planck Institute for Evolutionary Anthropology has finally sequenced enough nuclear DNA from fossils of a tooth and a leg bone from the pit to solve the mystery. The task was especially challenging because the ancient DNA was degraded to short fragments, made up of as few as 25 to 40 single nucleotides. (Nucleotides—also known as base pairs—are the building blocks of DNA.) Although he and his colleagues did not sequence the entire genomes of the fossils, Meyer reported at the meeting that they did get 1 million to 2 million base pairs of ancient nuclear DNA.

    DNA from Neanderthal relative may shake up human family tree
    Researchers have spent decades studying the remains found in the 'Pit of Bones', 
    reconstructing the skull shown above, which revealed it had suffered a 
    heavy blow to the head before death [Credit: msf]

    They scanned this DNA for unique markers found only in Neanderthals or Denisovans or modern humans, and found that the two Sima fossils shared far more alleles—different nucleotides at the same address in the genome—with Neanderthals than Denisovans or modern humans. “Indeed, the Sima de los Huesos specimens are early Neanderthals or related to early Neanderthals,” suggesting that the split of Denisovans and Neanderthals should be moved back in time, Meyer reported at the meeting.

    Researchers at the meeting were impressed by this new breakthrough in ancient DNA research. “This has been the next frontier with ancient DNA,” says evolutionary biologist Greger Larson of the University of Oxford in the United Kingdom.

    The close affinity with Neanderthals, but not with Denisovans or modern humans, suggests that the lineage leading to Neanderthals was separate from other archaic humans earlier than most researchers have thought. That means that the ancestors of modern humans also had to split earlier than expected from the population that gave rise to Neanderthals and Denisovans, who were more closely related to each other than they were to modern humans. (Although all three groups interbred at low levels after their evolutionary paths diverged—and such interbreeding may have been the source of the Denisovan mtDNA in the first Sima fossil whose DNA was sequenced.) Indeed, Meyer suggested in his talk that the ancestors of H. sapiens may have diverged from the branch leading to Neanderthals and Denisovans as early as 550,000 to 765,000 years ago, although those results depend on different mutation rates in humans and are still unpublished.

    That would mean that the ancestors of humans were already wandering down a solitary path apart from the other kinds of archaic humans on the planet 100,000 to 400,000 years earlier than expected. “It resolves one controversy—that they’re in the Neanderthal clade,” says paleoanthropologist Chris Stringer of the Natural History Museum in London. “But it’s not all good news: From my point of view, it pushes back the origin of H. sapiens from the Neanderthals and Denisovans.” The possibility that humans were a distinct group so early shakes up the human family tree, promising to lead to new debate about when and where the branches belong.

    Author: Ann Gibbons | Source: ScienceMag/AAAS [September 11, 2015]

  • Great Legacy: Fossils and minerals take the antiques market by storm

    Great Legacy: Fossils and minerals take the antiques market by storm

    Throughout the Renaissance, the demand for antiques among the aristocracy burgeoned, with the trend soaring by the late 17th century as members of the upper classes began scouring Europe in search of bronzes, sculptures, prints, lamps and vases. With disposable income then rising among the aspiring middle classes in the latter part of the 19th century, the bourgeoisie took to investing in their homes and in the finer things as well. As antiques went mainstream, the market boomed in the hubs of London and Paris.

    Fossils and minerals take the antiques market by storm
    The antiques market may be shrinking at a concerning rate but a new desire for the prehistoric
    is having its own revival [Credit: European CEO]

    However, despite this generally rising appetite, antiques have a tendency to go in and out of fashion, as evidenced by the lulls in between the booms of the 1950s and 1980s. At present, the market is experiencing yet another lull; new tastes and values have sent demand and prices for antiques crashing, leaving armoires, bejewelled knick-knacks and Regency dining chairs unwanted and unsold, and causing many industry players to close down or change course entirely. Yet, in the midst of all the doom and gloom for antiques aficionados, there is some cause for optimism in a few niche areas, especially when it comes to fossils and minerals.

    Out with the old

    With so many more people living in smaller abodes these days – urban dwellers in particular – there is very little space for antique desks and looming tapestries. Nor, in fact, do such items match contemporary tastes, as interior design trends have changed considerably over the past decade or two. Sleek and modern pieces, airy spaces and overall functionality are the style du jour; cluttered rooms and bulky furniture seem to have little place in 21st century life.

    “In general, young people have lost interest, and it is mostly older people who are buying – and obviously this area of the population is one that declines”, said Errol Fuller, a curator at Summers Place Auctions, and a leading expert on fossils and extinct species. “Not all areas of antique collecting are in retreat; it is the more drab brown furniture and traditional items that young people have little interest in. They look old-hat and boring.”

    Given the niche knowledge and training required to even begin delving into the subject, Baby Boomers and Millennials are largely uninterested in antiques. Adding further to this growing indifference is the reputation antiques have for popularity among the older generations – a status consolidated by television programmes, such as the US and UK versions of Antiques Roadshow, that depict the field as a hobby for pensioners. The downsizing of former antiques hubs, such as London’s Fulham Road and New York’s Kentshire Gardens, reflects this shift further still, indicating the market in general has indeed reached a precarious state.

    In with the even older

    Over the past year or so, one big trend that is offering hope to those in the trade is the growing popularity of fossils and minerals.

    “Decorative items, or things with intrinsic interest, still have appeal, and fossils and minerals have much of this quality. As do antique stuffed animals and birds. And it is these kind of things that are appealing to the young”, Fuller said. “The general public is becoming increasingly interested in the natural world – perhaps because we realise that much of it is vanishing at an alarming rate. We are becoming more conscious of anything to do with nature and to call a piece of natural history your own and to look after it for a few more years and save it for generations to come, is quite special.”

    This interest in the natural can be seen across numerous sectors and industries: food, make-up and alternative therapies, to name but a few. It would seem, as these trends indicate, that people are done with the artificial and are tired of fakery; they yearn for something with authenticity. Items such as fossils and minerals offer a window into the natural world within one’s own home.

    “Some are incredibly rare as well. But I think the main point is that most people are in sheer awe when they look at something that was created millions of years ago and which is still appealing to us”, said Fuller. “To imagine that this fossilised dinosaur or crab used to live on this planet such a long time ago, and is now one of the prized possessions in your collection is quite mind-blowing. Antiques and the amazing craftsmanship used to create them will always attract us, but I think it is the fact that fossils are not man-made that makes us look at them in wonder.”

    Crucial to this trend is the fact that fossils and minerals complement almost any type of interior design. They offer contrast to a modern room with soft furnishings, yet not in the garish way that a cumbersome 17th century dining table might. Given the variety of sizes, colours and types available, there is something for everyone and every budget. “Fossils are also still reasonably priced, so are more accessible to the general public and not restricted to those with millions in their bank accounts”, Fuller said.

    Their backgrounds make talking points like no other; it’s impossible not to be interested in their age, formation and aesthetic value.

    “They are not man-made and, in terms of antiquity, they are much older. And, of course, they almost always have a story”, Fuller said. “People tend to buy antiques because they are interested in their history and they look great in their homes. Fossils and minerals tick all those boxes, but as our homes are getting more contemporary, fossils actually fit in better. They look better in a minimalist home than most antiques, while still being quirky enough to be a real focal point.”

    When asked if he sees this trend continuing in the coming years, Fuller’s response was clear: “Absolutely, and especially because it is an area in which young people are becoming particularly interested, for all the above reasons. Summers Place Auctions established specific natural history sales with our first Evolution sale in 2013, but we have since gone from one specialist auction a year to including natural history items in all our sales – four in total. There is always a huge interest, but our last sale, which included the natural history collection of the Emmen Zoo, was the best yet – every single lot sold. We offered items at prices as low as £30, up to over £100,000.”

    Cyclical nature

    As shown throughout history, the trend for antiques in the home comes in waves. Wider phenomena, it would seem, have a large role to play; something may occur in popular culture that can ignite a craze, and a shift within an economy can spur a new trend. Take the hit show Mad Men; watched by millions and considered by many to be one of the greatest dramas of all time, the programme, which depicted life in a New York advertising agency in the 1960s, had a direct impact on the antique market. As the show’s popularity grew, so did that of sleek mid-century furniture, with sales of pieces by Charles and Ray Eames, and Jean-Michel Frank soaring during the show’s run. However, sales of such items have begun to slow once more since the show ended in 2015, demonstrating the fickle nature of tastes and trends when it comes to interior design, popular culture and what’s ‘in’.

    The growing demand for Chinese antiquities offers another important lesson for the antiques world. Given the exponential growth in the Chinese economy over the past three decades, a huge social shift has taken place in the country, with a sizeable middle class now present for the first time in the country’s history. This expansion and growth in disposable income has allowed considerably more people in China to own their own homes and, consequently, to invest in them and in objects of aesthetic value. Interestingly, this shift has taken place at the same time as a significant cultural transition within the country, whereby symbols of the past, which were once neglected and even rejected, have regained their prominence. Until recently, all reminders of the China’s imperial past were overlooked by the ruling regime and, as a result, the public. However, a renewed zeal for Chinese history has seen citizens reach out for objects of cultural significance. This trend has led Chinese buyers to scour the globe in search of rare pieces.

    The western trend for fossils and minerals may be in line with contemporary tastes, yet this too is likely to pass at some point – it may take several years, but it will pass. Evidently, the appetite for antiques, and for the various individual categories themselves, comes and goes. They are a reflection of society, the state of the economy, and of what was valued at any one time. At present, we are at a stage where the natural is lovingly embraced, which is clearly reflected in what we eat and how we style our homes. But the future may look very different. Perhaps period decor will come back into fashion, perhaps the dining room will have a revival, and maybe even large brown furniture will have its day once more.

    Ultimately, the antiques market has a life of its own. It has its own ebb and flow, and is certainly an interesting reflection of society. Although the antique market is shrinking in general, all is not lost for those invested in it; who knows what we’ll once again value in the future?

    Author: Elizabeth Matsangou | Source: European CEO [July 19, 2016]

  • East Asia: How China is rewriting the book on human origins

    East Asia: How China is rewriting the book on human origins

    On the outskirts of Beijing, a small limestone mountain named Dragon Bone Hill rises above the surrounding sprawl. Along the northern side, a path leads up to some fenced-off caves that draw 150,000 visitors each year, from schoolchildren to grey-haired pensioners. It was here, in 1929, that researchers discovered a nearly complete ancient skull that they determined was roughly half a million years old. Dubbed Peking Man, it was among the earliest human remains ever uncovered, and it helped to convince many researchers that humanity first evolved in Asia.

    How China is rewriting the book on human origins
    The reconstructed skull of Peking Man, the fossil that launched discussions 
    of human origins in China [Credit: DeAgostini/Getty]

    Since then, the central importance of Peking Man has faded. Although modern dating methods put the fossil even earlier—at up to 780,000 years old—the specimen has been eclipsed by discoveries in Africa that have yielded much older remains of ancient human relatives. Such finds have cemented Africa's status as the cradle of humanity—the place from which modern humans and their predecessors spread around the globe—and relegated Asia to a kind of evolutionary cul-de-sac.

    But the tale of Peking Man has haunted generations of Chinese researchers, who have struggled to understand its relationship to modern humans. "It's a story without an ending," says Wu Xinzhi, a palaeontologist at the Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing. They wonder whether the descendants of Peking Man and fellow members of the species Homo erectus died out or evolved into a more modern species, and whether they contributed to the gene pool of China today.

    Keen to get to the bottom of its people's ancestry, China has in the past decade stepped up its efforts to uncover evidence of early humans across the country. It is reanalysing old fossil finds and pouring tens of millions of dollars a year into excavations. And the government is setting up a US$1.1-million laboratory at the IVPP to extract and sequence ancient DNA.

    The investment comes at a time when palaeoanthropologists across the globe are starting to pay more attention to Asian fossils and how they relate to other early hominins—creatures that are more closely related to humans than to chimps. Finds in China and other parts of Asia have made it clear that a dazzling variety of Homo species once roamed the continent. And they are challenging conventional ideas about the evolutionary history of humanity.

    "Many Western scientists tend to see Asian fossils and artefacts through the prism of what was happening in Africa and Europe," says Wu. Those other continents have historically drawn more attention in studies of human evolution because of the antiquity of fossil finds there, and because they are closer to major palaeoanthropology research institutions, he says. "But it's increasingly clear that many Asian materials cannot fit into the traditional narrative of human evolution."

    Chris Stringer, a palaeoanthropologist at the Natural History Museum in London, agrees. "Asia has been a forgotten continent," he says. "Its role in human evolution may have been largely under-appreciated."

    Evolving story

    In its typical form, the story of Homo sapiens starts in Africa. The exact details vary from one telling to another, but the key characters and events generally remain the same. And the title is always 'Out of Africa'.

    How China is rewriting the book on human origins

    In this standard view of human evolution, H. erectus first evolved there more than 2 million years ago. Then, some time before 600,000 years ago, it gave rise to a new species: Homo heidelbergensis, the oldest remains of which have been found in Ethiopia. About 400,000 years ago, some members of H. heidelbergensis left Africa and split into two branches: one ventured into the Middle East and Europe, where it evolved into Neanderthals; the other went east, where members became Denisovans—a group first discovered in Siberia in 2010. The remaining population of H. heidelbergensis in Africa eventually evolved into our own species, H. sapiens, about 200,000 years ago. Then these early humans expanded their range to Eurasia 60,000 years ago, where they replaced local hominins with a minuscule amount of interbreeding.

    A hallmark of H. heidelbergensis—the potential common ancestor of Neanderthals, Denisovans and modern humans—is that individuals have a mixture of primitive and modern features. Like more archaic lineages, H. heidelbergensis has a massive brow ridge and no chin. But it also resembles H. sapiens, with its smaller teeth and bigger braincase. Most researchers have viewed H. heidelbergensis—or something similar—as a transitional form between H. erectus and H. sapiens.

    Unfortunately, fossil evidence from this period, the dawn of the human race, is scarce and often ambiguous. It is the least understood episode in human evolution, says Russell Ciochon, a palaeoanthropologist at the University of Iowa in Iowa City. "But it's central to our understanding of humanity's ultimate origin."

    The tale is further muddled by Chinese fossils analysed over the past four decades, which cast doubt over the linear progression from African H. erectus to modern humans. They show that, between roughly 900,000 and 125,000 years ago, east Asia was teeming with hominins endowed with features that would place them somewhere between H. erectus and H. sapiens, says Wu.

    "Those fossils are a big mystery," says Ciochon. "They clearly represent more advanced species than H. erectus, but nobody knows what they are because they don't seem to fit into any categories we know."

    How China is rewriting the book on human origins

    The fossils' transitional characteristics have prompted researchers such as Stringer to lump them with H. heidelbergensis. Because the oldest of these forms, two skulls uncovered in Yunxian in Hubei province, date back 900,000 years >1, 2>, Stringer even suggests that H. heidelbergensis might have originated in Asia and then spread to other continents.

    But many researchers, including most Chinese palaeontologists, contend that the materials from China are different from European and African H. heidelbergensis fossils, despite some apparent similarities. One nearly complete skull unearthed at Dali in Shaanxi province and dated to 250,000 years ago, has a bigger braincase, a shorter face and a lower cheekbone than most H. heidelbergensis specimens>3, suggesting that the species was more advanced.

    Such transitional forms persisted for hundreds of thousands of years in China, until species appeared with such modern traits that some researchers have classified them as H. sapiens. One of the most recent of these is represented by two teeth and a lower jawbone, dating to about 100,000 years ago, unearthed in 2007 by IVPP palaeoanthropologist Liu Wu and his colleagues>4. Discovered in Zhirendong, a cave in Guangxi province, the jaw has a classic modern-human appearance, but retains some archaic features of Peking Man, such as a more robust build and a less-protruding chin.

    Most Chinese palaeontologists—and a few ardent supporters from the West—think that the transitional fossils are evidence that Peking Man was an ancestor of modern Asian people. In this model, known as multiregionalism or continuity with hybridization, hominins descended from H. erectus in Asia interbred with incoming groups from Africa and other parts of Eurasia, and their progeny gave rise to the ancestors of modern east Asians, says Wu.

    Support for this idea also comes from artefacts in China. In Europe and Africa, stone tools changed markedly over time, but hominins in China used the same type of simple stone instruments from about 1.7 million years ago to 10,000 years ago. According to Gao Xing, an archaeologist at the IVPP, this suggests that local hominins evolved continuously, with little influence from outside populations.

    Politics at play?

    Some Western researchers suggest that there is a hint of nationalism in Chinese palaeontologists' support for continuity. "The Chinese—they do not accept the idea that H. sapiens evolved in Africa," says one researcher. "They want everything to come from China."

    Chinese researchers reject such allegations. "This has nothing to do with nationalism," says Wu. It's all about the evidence—the transitional fossils and archaeological artefacts, he says. "Everything points to continuous evolution in China from H. erectus to modern human."

    But the continuity-with-hybridization model is countered by overwhelming genetic data that point to Africa as the wellspring of modern humans. Studies of Chinese populations show that 97.4% of their genetic make-up is from ancestral modern humans from Africa, with the rest coming from extinct forms such as Neanderthals and Denisovans>5. "If there had been significant contributions from Chinese H. erectus, they would show up in the genetic data," says Li Hui, a population geneticist at Fudan University in Shanghai. Wu counters that the genetic contribution from archaic hominins in China could have been missed because no DNA has yet been recovered from them.

    Many researchers say that there are ways to explain the existing Asian fossils without resorting to continuity with hybridization. The Zhirendong hominins, for instance, could represent an exodus of early modern humans from Africa between 120,000 and 80,000 years ago. Instead of remaining in the Levant in the Middle East, as was thought previously, these people could have expanded into east Asia, says Michael Petraglia, an archaeologist at the University of Oxford, UK.

    How China is rewriting the book on human origins
    Dozens of teeth from a cave in Daoxian, China, have been attributed to modern humans 
    and date to 120,000–80,000 years ago [Credit: S. Xing and X-J. Wu]

    Other evidence backs up this hypothesis: excavations at a cave in Daoxian in China's Hunan province have yielded 47 fossil teeth so modern-looking that they could have come from the mouths of people today. But the fossils are at least 80,000 years old, and perhaps 120,000 years old, Liu and his colleagues reported last year>6. "Those early migrants may have interbred with archaic populations along the way or in Asia, which could explain Zhirendong people's primitive traits," says Petraglia.

    Another possibility is that some of the Chinese fossils, including the Dali skull, represent the mysterious Denisovans, a species identified from Siberian fossils that are more than 40,000 years old. Palaeontologists don't know what the Denisovans looked like, but studies of DNA recovered from their teeth and bones indicate that this ancient population contributed to the genomes of modern humans, especially Australian Aborigines, Papua New Guineans and Polynesians—suggesting that Denisovans might have roamed Asia.

    Maria Martinon-Torres, a palaeoanthropologist at University College London, is among those who proposed that some of the Chinese hominins were Denisovans. She worked with IVPP researchers on an analysis>7, published last year, of a fossil assemblage uncovered at Xujiayao in Hebei province—including partial jaws and nine teeth dated to 125,000–100,000 years ago. The molar teeth are massive, with very robust roots and complex grooves, reminiscent of those from Denisovans, she says.

    A third idea is even more radical. It emerged when Martinon-Torres and her colleagues compared more than 5,000 fossil teeth from around the world: the team found that Eurasian specimens are more similar to each other than to African ones>8. That work and more recent interpretations of fossil skulls suggest that Eurasian hominins evolved separately from African ones for a long stretch of time. The researchers propose that the first hominins that left Africa 1.8 million years ago were the eventual source of modern humans. Their descendants mostly settled in the Middle East, where the climate was favourable, and then produced waves of transitional hominins that spread elsewhere. One Eurasian group went to Indonesia, another gave rise to Neanderthals and Denisovans, and a third ventured back into Africa and evolved into H. sapiens, which later spread throughout the world. In this model, modern humans evolved in Africa, but their immediate ancestor originated in the Middle East.

    Not everybody is convinced. "Fossil interpretations are notoriously problematic," says Svante Paabo, a palaeogeneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. But DNA from Eurasian fossils dating to the start of the human race could help to reveal which story—or combination—is correct. China is now making a push in that direction. Qiaomei Fu, a palaeogeneticist who did her PhD with Paabo, returned home last year to establish a lab to extract and sequence ancient DNA at the IVPP. One of her immediate goals is to see whether some of the Chinese fossils belong to the mysterious Denisovan group. The prominent molar teeth from Xujiayao will be an early target. "I think we have a prime suspect here," she says.

    Fuzzy picture

    Despite the different interpretations of the Chinese fossil record, everybody agrees that the evolutionary tale in Asia is much more interesting than people appreciated before. But the details remain fuzzy, because so few researchers have excavated in Asia.

    When they have, the results have been startling. In 2003, a dig on Flores island in Indonesia turned up a diminutive hominin>9, which researchers named Homo floresiensis and dubbed the hobbit. With its odd assortment of features, the creature still provokes debate about whether it is a dwarfed form of H. erectus or some more primitive lineage that made it all the way from Africa to southeast Asia and lived until as recently as 60,000 years ago. Last month, more surprises emerged from Flores, where researchers found the remains of a hobbit-like hominin in rocks about 700,000 years old>10.

    Recovering more fossils from all parts of Asia will clearly help to fill in the gaps. Many palaeoanthropologists also call for better access to existing materials. Most Chinese fossils—including some of the finest specimens, such as the Yunxian and Dali skulls—are accessible only to a handful of Chinese palaeontologists and their collaborators. "To make them available for general studies, with replicas or CT scans, would be fantastic," says Stringer. Moreover, fossil sites should be dated much more rigorously, preferably by multiple methods, researchers say.

    But all agree that Asia—the largest continent on Earth—has a lot more to offer in terms of unravelling the human story. "The centre of gravity," says Petraglia, "is shifting eastward."

    Author: Jane Qiu | Source: Nature 535, 22–25 (14 July 2016) doi:10.1038/535218a [July 15, 2016]

  • Morocco: Spectacular Moroccan fossils redefine evolutionary timelines

    Morocco: Spectacular Moroccan fossils redefine evolutionary timelines

    Some of the oldest marine animals on the planet, including armoured worm-like forms and giant, lobster like sea creatures, survived millions of years longer than previously thought, according to a spectacularly preserved fossil formation from southeastern Morocco.

    Spectacular Moroccan fossils redefine evolutionary timelines
    A marrellomorph arthropod, probably belonging to the genus Furca 
    [Credit: Marianne Collins, ArtofFact]

    The Lower Fezouata formation has been revealing exciting discoveries about life in the Ordovician -- around 485 -- 444 million years ago -- since its discovery just five years ago.

    'The Fezouata is extraordinarily significant' says Professor Derek Briggs of Yale University, co-author of a study published today in the Journal of the Geological Society. 'Animals typical of the Cambrian are still present in rocks 20 million years younger, which means there must be a cryptic record in between, which is not preserved.'

    Spectacular Moroccan fossils redefine evolutionary timelines
    The oldest representative of the cheloniellid arthropods, 
    which range to the Devonian [Credit: Peter Van Roy]

    Over 160 genera have already been documented from the Fezouata, with much more expected to be found. They include animals which would have looked perfectly at home during the Cambrian: armoured lobopodians -- worm like creatures with spines on their backs and short, stubby legs, and anomalocaridids -- huge segmented animals with remarkable feeding limbs, which are some of the largest marine creatures of the time.

    As well as demonstrating the longevity of fauna thought to have been extinct millions of years previously, the Fezouata proves that other creatures evolved far earlier than previously thought.

    Spectacular Moroccan fossils redefine evolutionary timelines
    The oldest horseshoe crab, a subadult specimen showing
     the fused segments at the rear characteristic of
     living horseshoe crabs [Credit: Peter Van Roy]

    'Horseshoe crabs, for example, turn out to be at least 20 million years older than we thought. The formation demonstrates how important exceptionally preserved fossils are to our understanding of major evolutionary events in deep time' says Peter Van Roy, also of Yale, who first recognised the scientific importance of the Fezouata fauna and is lead author of the study, part of a project funded by the National Science Foundation.

    The spectacular preservation, which includes detailed soft parts and organisms over 2 metres in length, is thanks to the fine grained, muddy sediments in which the organisms were preserved.

    Spectacular Moroccan fossils redefine evolutionary timelines
    Aegirocassis benmoulai, a giant filter-feeding anomalocaridid preserved in
     three dimensions within a concretion. Two sets of swimming flaps are 
    evident on the left side of the trunk [Credit: Peter Van Roy]

    'These are special rocks' says Professor Briggs. 'Some of the organisms are enormous -- several metres in length. With such exceptional preservation, in a fully marine exposure, we can develop a reasonably full picture of what marine life looked like in the Ordovician.'

    The discoveries suggest the 'Great Ordovician Biodiversification Event' -- an explosion in diversity throughout the earlier part of the Ordovician period -- may have been a continuation of the Cambrian explosion.

    Spectacular Moroccan fossils redefine evolutionary timelines
    Aegirocassis benmoulai reconstruction 
    [Credit: Marianne Collins/ArtofFact]

    'There is much more to learn from the Fezouata' says Professor Briggs. 'Why do we not see more assemblages like this in the Ordovician? What ecological changes happened at the Cambro-Ordovician interval? Are the Cambrian Explosion and the Great Ordovician Biodiversification Event separate, or phases of the same event?'

    Source: Geological Society of London [July 07, 2015]

  • Palaeontology: Newly discovered pliosaur terrorised ancient Russian seas

    Palaeontology: Newly discovered pliosaur terrorised ancient Russian seas

    The Mesozoic played host to some of the most dangerous predators to ever swim the Earth's oceans. Among these, pliosaurs were lethal hunters, and some of the largest predators ever on this planet. They were the shorter-necked cousins of the plesiosaurs, which are often spoken of in reference to their superficial similarity to the Loch Ness Monster, which we're definitely not going to do here. Together, pliosaurs and plesiosaurs form a group known as Sauropterygia, which existed in the oceans from the Triassic right until the end of the Cretaceous, when they went extinct along with the non-avian dinosaurs and other vertebrate groups. This actually makes sauropterygians the longest living group of marine-adapted tetrapods (animals with four limbs), which is quite an impressive feat!

    Newly discovered pliosaur terrorised ancient Russian seas
    Fossils of the new pliosaur, Makhaira [Credit: Fischer et al. 2015]

    New discoveries show that perhaps this evolutionary success can be attributed to the ecological diversity that this group possessed, and in particular an ability to adapt to different feeding styles.

    Valentin Fischer from the University of Oxford and an international team of researchers have discovered a new pliosaur from western Russia, named Makhaira rossica. The name dreives from the Latinized Ancient Greek word 'mákhaira', which describes a blade with a curved outline, as well as the Latin word 'rossica', which means Russian. The specimen comprises a fragmentary skeleton of a sub-adult animal, found within a series of limestone nodules along the banks of the Volga River.

    Makhaira comes from a period in Earth's geological history, known as the earliest part of the Cretaceous, where our knowledge of vertebrate life is relatively poor due to the way in which fossils are differentially preserved through time. Sadly, this lack of knowledge means that our understanding of how faunas changed from the latest part of the Jurassic period into the first part of the Cretaceous is relatively poor compared to other important geological boundaries.

    Analysis of the evolutionary placement of this new species places it as the most basal member of a group known as Brachaucheninae, which survived through the Cretaceous. However, the new species is different in being a little smaller than some of its more advanced relatives.

    Newly discovered pliosaur terrorised ancient Russian seas
    Evolutionary relationships of Makhaira with other Jurassic and Cretaceous pliosaurs 
    [Credit: Fischer et al. 2015]

    The weirdest feature of the new beasty has to be the teeth. The teeth occur in pairs, and have a trihedral form, meaning they had three peaks on each alveolus, and the edges of the teeth were adorned with wicked serrations. They were also very large, similar even to some teeth from theropod dinosaurs roaming the lands at the time!

    The morphology of these teeth suggest that they were equipped just for one thing – devouring other large animals! This form of feeding is known as macrophagy, and was a common form of predation at the time for giant marine crocodyliforms (the ancestors of modern crocodiles) called metriorhynchids. Importantly, this feeding style previously seemed to have been lost in the early evolution of other brachauchenine pliosaurs, but now appears to have been present in at least one species from this group. This shows that Early Cretaceous pliosaurs were still well adapted to hypercarnivory, and retained a high feeding diversity at the beginning of the Cretaceous, and not lost from their Jurassic ancestors.

    Recently, Alessandro Chiarenza, a colleague of mine at Imperial College London, reported on what appeared to be the oldest metriorhynchid remains currently known, from a fossil site in Sicily. Based on a single fossilised tooth from a period known as the Aptian, later on in the Cretaceous than when Makhaira was found, these remains extended the duration of metriorhynchids, and their eventual extinction, by several millions of years.

    However, the morphology of the teeth of Makhaira wasn't known at the time of publishing the crocodyliform fossils, and it seems that it is actually impossible to distinguish between these and the teeth of some metriorhynchids. This means that the Sicilian tooth cannot be referred unequivocally to either a metriorhynchid or a pliosaur – the teeth of some species is just too similar to say for certain! What does this imply though? Well, it seems that the fate of metriorhynchids is still a mystery concealed by the fossil record, and is only something that future study of these fossils, their other monstrous counterparts, and discovery of new fossils can hope to solve!

    The findings are published in the >Royal Society Open Science journal.

    Author: Victoria Costello | Source: Public Library of Science [January 16, 2016]

  • Fossils: Mammal diversity exploded immediately after dinosaur extinction

    Fossils: Mammal diversity exploded immediately after dinosaur extinction

    The diversity of mammals on Earth exploded straight after the dinosaur extinction event, according to UCL researchers. New analysis of the fossil record shows that placental mammals, the group that today includes nearly 5000 species including humans, became more varied in anatomy during the Paleocene epoch - the 10 million years immediately following the event.

    Mammal diversity exploded immediately after dinosaur extinction
    Leptictis [Credit: Dr Thomas Halliday]

    Senior author, Dr Anjali Goswami (UCL Genetics, Evolution & Environment), said: "When dinosaurs went extinct, a lot of competitors and predators of mammals disappeared, meaning that a great deal of the pressure limiting what mammals could do ecologically was removed. They clearly took advantage of that opportunity, as we can see by their rapid increases in body size and ecological diversity. Mammals evolved a greater variety of forms in the first few million years after the dinosaurs went extinct than in the previous 160 million years of mammal evolution under the rule of dinosaurs."

    The Natural Environment Research Council-funded research, published today in the Biological Journal of the Linnean Society, studied the early evolution of placental mammals, the group including elephants, sloths, cats, dolphins and humans. The scientists gained a deeper understanding of how the diversity of the mammals that roamed the Earth before and after the dinosaur extinction changed as a result of that event.

    Placental mammal fossils from this period have been previously overlooked as they were hard to place in the mammal tree of life because they lack many features that help to classify the living groups of placental mammals. Through recent work by the same team at UCL, this issue was resolved by creating a new tree of life for placental mammals, including these early forms, which was described in a study published in Biological Reviews yesterday.

    First author of both papers, Dr Thomas Halliday (UCL Earth Sciences and Genetics, Evolution & Environment), said: "The mass extinction that wiped out the dinosaurs 66 million years ago is traditionally acknowledged as the start of the 'Age of Mammals' because several types of mammal appear for the first time immediately afterwards.

    "Many recent studies suggest that little changed in mammal evolution during the Paleocene but these analyses don't include fossils from that time. When we look at the mammals that were present, we find a burst of evolution into new forms, followed by specialisation that finally resulted in the groups of mammals we see today. The earliest placental mammal fossils appear only a few hundred thousand years after the mass extinction, suggesting the event played a key role in diversification of the mammal group to which we belong."

    The team studied the bones and teeth of 904 placental fossils to measure the anatomical differences between species. This information was used to build an updated tree of life containing 177 species within Eutheria (the group of mammals including all species more closely related to us than to kangaroos) including 94 from the Paleocene - making it the tree with the largest representation from Paleocene mammals to date. The new tree was analysed in time sections from 140 million years ago to present day, revealing the change in the variety of species.

    Three different methods were used by the team to investigate the range and variation of the mammals present and all showed an explosion in mammal diversity after the dinosaur extinction. This is consistent with theories that mammals flourished when dinosaurs were no longer hunting them or competing with them for resources.

    Dr Anjali Goswami (UCL Genetics, Evolution & Environment), added: "Extinctions are obviously terrible for the groups that go extinct, non-avian dinosaurs in this case, but they can create great opportunities for the species that survive, such as placental mammals, and the descendants of dinosaurs: birds."

    Professor Paul Upchurch (UCL Earth Sciences), co-author of the Biological Reviews study, added: "Several previous methodological studies have shown that it is important to include as many species in an evolutionary tree as possible: this generally improves the accuracy of the tree. By producing such a large data set, we hope that our evolutionary tree for Paleocene mammals is more robust and reliable than any of the previous ones. Moreover, such large trees are very useful for future studies of large-scale evolutionary patterns, such as how early placental mammals dispersed across the continents via land bridges that no longer exist today."

    The team are now investigating rates of evolution in these mammals, as well as looking at body size more specifically. Further work will involve building data from DNA into these analyses, to extend these studies to modern mammals.

    Source: University College London [December 21, 2015]

  • Fossils: 520-million-year-old arthropod brains turn paleontology on its head

    Fossils: 520-million-year-old arthropod brains turn paleontology on its head

    Science has long dictated that brains don't fossilize, so when Nicholas Strausfeld co-authored the first ever report of a fossilized brain in a 2012 edition of Nature, it was met with "a lot of flack."

    520-million-year-old arthropod brains turn paleontology on its head
    A: Under a light microscope, the above fossil shows traces of preserved neural
     tissues in black. B: An elemental scan of this fossil uncovered that carbon (in pink)
     and iron (in green) do not overlap in the preserved neural tissue 
    [Credit: Strausfeld et al. and Current Biology]

    "It was questioned by many paleontologists, who thought - and in fact some claimed in print - that maybe it was just an artifact or a one-off, implausible fossilization event," said Strausfeld, a Regents' professor in UA's Department of Neuroscience.

    His latest paper in Current Biology addresses these doubts head-on, with definitive evidence that, indeed, brains do fossilize.

    In the paper, Strausfeld and his collaborators, including Xiaoya Ma of Yunnan Key Laboratory for Palaeobiology at China's Yunnan University and Gregory Edgecombe of the Natural History Museum in London, analyze seven newly discovered fossils of the same species to find, in each, traces of what was undoubtedly a brain.

    The species, Fuxianhuia protensa, is an extinct arthropod that roamed the seafloor about 520 million years ago. It would have looked something like a very simple shrimp. And each of the fossils - from the Chengjiang Shales, fossil-rich sites in Southwest China - revealed F. protensa's ancient brain looked a lot like a modern crustacean's, too.

    520-million-year-old arthropod brains turn paleontology on its head
    Tracings of two newly discovered fossilized brains are superimposed 
    upon the original Fuxianhuia protensa sample from 2012
    [Credit: Strausfeld et al. and Current Biology]

    Using scanning electron microscopy, the researchers found that the brains were preserved as flattened carbon films, which, in some fossils, were partially overlaid by tiny iron pyrite crystals. This led the research team to a convincing explanation as to how and why neural tissue fossilizes.

    In another recent paper in Philosophical Transactions of the Royal Society B, Strausfeld's experiments uncovered what it likely was about ancient environmental conditions that allowed a brain to fossilize in the first place.

    The only way to become fossilized is, first, to get rapidly buried. Hungry scavengers can't eat a carcass if it's buried, and as long as the water is anoxic enough - that is, lacking in oxygen - a buried creature's tissues evade consumption by bacteria as well. Strausfeld and his collaborators suspect F. protensa was buried by rapid, underwater mudslides, a scenario they experimentally recreated by burying sandworms and cockroaches in mud.

    This is only step one. Step two, explained Strausfeld, is where most brains would fail: Withstanding the pressure from being rapidly buried under thick, heavy mud.

    520-million-year-old arthropod brains turn paleontology on its head
    A Fuxianhuia protensa specimen from the Chenjiang fossil beds in southwest China. 
    The ancient arthropod was 12 centimeters (just under 5 inches) in length 
    [Credit: Xiaoya Ma, London Museum of Natural History]

    To have been able to do this, the F. protensa nervous system must have been remarkably dense. In fact, tissues of nervous systems, including brains, are densest in living arthropods. As a small, tightly packed cellular network of fats and proteins, the brain and central nervous system could pass step two, just as did the sandworm and cockroach brains in Strausfeld's lab.

    "Dewatering is different from dehydration, and it happens more gradually," said Strausfeld, referring to the process by which pressure from the overlying mud squeezes water out of tissues. "During this process, the brain maintains its overall integrity leading to its gradual flattening and preservation. F. protensa's tissue density appears to have made all the difference."

    Now that he and his collaborators have produced unassailable evidence that fossilized arthropod brains are more than just a one-off phenomenon, Strausfeld is working to elucidate the origin and evolution of brains over half a billion years in the past.

    "People, especially scientists, make assumptions. The fun thing about science, actually, is to demolish them," said Strausfeld.

    Source: University of Arizona [November 06, 2015]

  • Fossils: Mammals evolved faster after dinosaur extinction

    Fossils: Mammals evolved faster after dinosaur extinction

    Our ancestors evolved three times faster in the 10 million years after the extinction of the dinosaurs than in the previous 80 million years, according to UCL researchers.

    Mammals evolved faster after dinosaur extinction
    Late cretaceous dinosaurs [Credit: UCL]

    The team found the speed of evolution of placental mammals -- a group that today includes nearly 5000 species including humans -- was constant before the extinction event but exploded after, resulting in the varied groups of mammals we see today.

    Lead researcher, Dr Thomas Halliday (UCL Genetics, Evolution & Environment), said: "Our ancestors -- the early placental mammals - benefitted from the extinction of non-avian dinosaurs and dwindling numbers of competing groups of mammals. Once the pressure was off, placental mammals suddenly evolved rapidly into new forms.

    "In particular, we found a group called Laurasiatheria quickly increased their body size and ecological diversity, setting them on a path that would result in a modern group containing mammals as diverse as bats, cats, rhinos, whales, cows, pangolins, shrews and hedgehogs."

    The team found that the last common ancestor for all placental mammals lived in the late Cretaceous period, about three million years before the non-avian dinosaurs became extinct 66 million years ago. This date is 20 million years younger than suggestions from previous studies which used molecular data from living mammals and assumed a near-constant rate of evolution.

    In this study, funded by the Natural Environment Research Council and published in >Proceedings B of the Royal Society, the researchers analysed fossils from the Cretaceous to the present day, and used the dates of their occurrence in the fossil record to estimate the timing of divergences based on an updated tree of life. The new tree was released by the same team in 2015 and has the largest representation of Paleocene mammals to date.

    The scientists measured all the small changes in the bones and teeth of 904 placental fossils and mapped the anatomical differences between species on the tree of life. From measuring the number of character changes over time for each branch, they found the average rate of evolution for early placental mammals both before and after the dinosaur extinction event. They compared the average rate of evolution over the geological stages before the extinction and the geological stages after to see what impact it had.

    Senior author, Professor Anjali Goswami (UCL Genetics, Evolution & Environment and UCL Earth Sciences), said: "Our findings refute those of other studies which overlooked the fossils of placental mammals present around the last mass extinction. Using rigorous methods, we've successfully tracked the evolution of early placental mammals and reconstructed how it changed over time. While the rate differed between species, we see a clear and massive spike in the rates of evolution straight after the dinosaurs become extinct, suggesting our ancestors greatly benefitted from the demise of the dinosaurs. The huge impact of the dinosaur extinction on the evolution of our ancestors really shows how important this event was in shaping the modern world."

    Professor Paul Upchurch (UCL Earth Sciences), co-author of the study, added: "Our large and refined data set allows us to build a clearer picture of evolutionary history. We plan on using it to study other large-scale evolutionary patterns such as how early placental mammals dispersed across the continents via land bridges that no longer exist today."

    Source: University College London [June 28, 2016]

  • Fossils: New Piltdown hoax analysis points to work of 'lone forger'

    Fossils: New Piltdown hoax analysis points to work of 'lone forger'

    The Piltdown Man scandal is arguably the greatest scientific fraud ever perpetrated in the UK, with fake fossils being claimed as evidence of our earliest ancestor.

    New Piltdown hoax analysis points to work of 'lone forger'
    The faked fossilized remains of Piltdown man (stained to look old), newspaper articles from the 1950s exposing the fraud.
      Inset: Charles Dawson, who the new article claims is probably the sole fraudster 
    [Credit: Natural History Museum]

    Published 100 years on from Dawson's death, new research reveals that the forgeries were created using a limited number of specimens that were all constructed using a consistent method, suggesting the perpetrator acted alone.

    It is highly likely that an orang-utan specimen and at least two human skeletons were used to create the fakes, which are still kept at the Natural History Museum.

    Between 1912 and 1914 Museum palaeontologist Arthur Smith Woodward and the amateur antiquarian Charles Dawson announced the discovery of fossils from Piltdown in Sussex. These were supposedly a new evolutionary link between apes and humans. They indicated a species with both an ape-like jaw and a large braincase like a modern human. Before he died in 1916, Dawson claimed to have discovered further evidence at a second site.

    The forgeries helped misdirect the study of anthropology for decades. While doubts were raised from the start, it took 40 years for the scientific community to recognise that the remains had been altered to seem ancient and had been planted in the sites.

    The new research, published in >Royal Society Open Science, was undertaken by a multi-disciplinary team from institutions in Liverpool, London, Cambridge and Canterbury. They used the latest scientific methods to test the Piltdown specimens to uncover more about how the forgery was done.

    New Piltdown hoax analysis points to work of 'lone forger'
    Surface modifications of Piltdown I M 1 : (A-B) photo and CT scans showing the material removal of the cusps in an 
    unnatural horizontal plane and enamel reconstruction on the lingual margin (C) Comparison of surface modifications 
    on different areas of the Piltdown I M 1 : Enamel (D), dentine (E), restorative putty (F), stained enamel (G)
    [Credit: De Groote et al./Natural History Museum]

    DNA analyses show that both the canine from the first Piltdown site and the molar from the second site probably came from one orang-utan, related most closely to orang-utans now occupying south-west Sarawak (Borneo). In addition, the shape and form of the molar from the second Piltdown site was almost certainly from the other side of the jawbone planted in the first site.

    3D X-ray imaging (Micro-CT scans) show that many of the bones and a tooth were filled with Piltdown gravel and the openings plugged with small pebbles. Holes in the skull bones were filled with dental putty, which was also used to re-set the teeth in the jaw and to reconstruct one of the teeth that fell apart while it was being ground down.

    Dr Laura Buck co-author on the paper from the Division of Biological Anthropology, University of Cambridge commented on the project's importance. "Even today, over a hundred years after the Piltdown fraud was perpetrated, it remains relevant because of the huge impact it had on the course of Palaeoanthropological research at the beginning of the twentieth century."

    "Fossil human remains from Africa, such as the Taung child from South Africa, were largely ignored when first found because they didn't fit with preconceptions of what an early human relative would look like, based on Piltdown Man. This serves as an important reminder to researchers today to study what is there and not what we think should be there," Buck said.

    Dr Isabelle De Groote from Liverpool John Moores University and lead author on the paper, thinks the results point to a clear conclusion: "Although multiple individuals have been accused of producing the fake fossils, our analyses to understand the modus operandi show consistency between all the different specimens and on both sites. It is clear from our analysis that this work was likely all carried out by one forger: Charles Dawson."

    Source: University of Cambridge [August 11, 2016]

  • Fossils: Long-necked dino species discovered in Australia

    Fossils: Long-necked dino species discovered in Australia

    The Australian Age of Dinosaurs Museum today announced the naming of Savannasaurus elliottorum, a new genus and species of dinosaur from western Queensland, Australia. The bones come from the Winton Formation, a geological deposit approximately 95 million years old.

    Long-necked dino species discovered in Australia
    >An artist's impression of the Savannasaurus elliottorum [Credit: Australian Age of Dinosaurs 
    >Museum of Natural History]

    Savannasaurus was discovered by David Elliott, co-founder of the Australian Age of Dinosaurs Museum, while mustering sheep in early 2005. As Elliott recalled yesterday, "I was nearly home with the mob -- only about a kilometre from the yards -- when I spotted a small pile of fossil bone fragments on the ground. I was particularly excited at the time as there were two pieces of a relatively small limb bone and I was hoping it might be a meat-eating theropod dinosaur." Mr Elliott returned to the site later that day to collect the bone fragments with his wife Judy, who 'clicked' two pieces together to reveal a complete toe bone from a plant-eating sauropod. The Elliotts marked the site and made arrangements to hold a dig later that year.

    The site was excavated in September 2005 by a joint Australian Age of Dinosaurs (AAOD) Museum and Queensland Museum team and 17 pallets of bones encased in rock were recovered. After almost ten years of painstaking work by staff and volunteers at the AAOD Museum, the hard siltstone concretion around the bones was finally removed to reveal one of the most complete sauropod dinosaur skeletons ever found in Australia. More excitingly, it belonged to a completely new type of dinosaur.

    The new discovery was nicknamed Wade in honour of prominent Australian palaeontologist Dr Mary Wade. "Mary was a very close friend of ours and she passed away while we were digging at the site," said Mr Elliott. "We couldn't think of a better way to honour her than to name the new dinosaur after her."

    Long-necked dino species discovered in Australia
    The dinosaur dig site in Winton where the bones have been painstakingly unearthed> 
    >[Credit: Australian Age of Dinosaurs Museum of Natural History]

    "Before today we have only been able to refer to this dinosaur by its nickname," said Dr Stephen Poropat, Research Associate at the AAOD Museum and lead author of the study. "Now that our study is published we can refer to Wade by its formal name, Savannasaurus elliottorum," Dr Poropat said. "The name references the savannah country of western Queensland in which it was found, and honours the Elliott family for their ongoing commitment to Australian palaeontology."

    In the same publication, Dr Poropat and colleagues announced the first sauropod skull ever found in Australia. This skull, and the partial skeleton with which it was associated, has been assigned to Diamantinasaurus matildae -- a sauropod dinosaur named in 2009 on the basis of its nickname Matilda. "This new Diamantinasaurus specimen has helped to fill several gaps in our knowledge of this dinosaur's skeletal anatomy," said Poropat. "The braincase in particular has allowed us to refine Diamantinasaurus' position on the sauropod family tree."

    Dr Poropat collaborated with British sauropod experts Dr Philip Mannion (Imperial College, London) and Professor Paul Upchurch (University College, London), among others, to work out the position of Savannasaurus (and refine that of Diamantinasaurus) on the sauropod family tree. "Both Savannasaurus and Diamantinasaurus belong to a group of sauropods called titanosaurs. This group of sauropods includes the largest land-living animals of all time," said Dr Mannion. "Savannasaurus and the new Diamantinasaurus specimen have helped us to demonstrate that titanosaurs were living worldwide by 100 million years ago."

    Long-necked dino species discovered in Australia
    >The fossils make up one of the most complete collection ever found in Australia> 
    >[Credit: Australian Age of Dinosaurs Museum of Natural History]

    Poropat and his colleagues suggest that the arrangement of the continents, and the global climate during the middle part of the Cretaceous Period, enabled titanosaurs to spread worldwide.

    "Australia and South America were connected to Antarctica throughout much of the Cretaceous," said Professor Upchurch. "Ninety-five million years ago, at the time that Savannasaurus was alive, global average temperatures were warmer than they are today. However, it was quite cool at the poles at certain times, which seems to have restricted the movement of sauropods at polar latitudes. We suspect that the ancestor of Savannasaurus was from South America, but that it could not and did not enter Australia until approximately 105 million years ago. At this time global average temperatures increased allowing sauropods to traverse landmasses at polar latitudes."

    Savannasaurus was a medium-sized titanosaur, approximately half the length of a basketball court, with a long neck and a relatively short tail. "With hips at least one metre wide and a huge barrel-like ribcage, Savannasaurus is the most rotund sauropod we have found so far -- even more so than the somewhat hippopotamus-like Diamantinasaurus," said Dr Poropat. "It lived alongside at least two other types of sauropod (Diamantinasaurus and Wintonotitan), as well as other dinosaurs including ornithopods, armoured ankylosaurs, and the carnivorous theropod Australovenator."

    Long-necked dino species discovered in Australia
    >Dr Stephen Poropat from the Australian Age of Dinosaurs Museum of Natural History in Winton, 
    >with five back vertebrae from the newly-discovered Australian dinosaur Savannasaurus elliottorum 
    >[Credit: Judy Elliott/Australian Age of Dinosaurs Museum of Natural History]

    Mr Elliott is relieved that Wade can now join "Matilda" and the other new dinosaur species on display in the Museum's Holotype Room. "That this dinosaur specimen can now be displayed for our visitors is a testament to the efforts of numerous volunteers who have worked at the Museum on the fossils over the past decade," he said. Mr Elliott and Dr Poropat agree that the naming of Savannasaurus, the fourth new species published by the AAOD Museum, is just the tip of the iceberg with respect to the potential for new dinosaur species in western Queensland.

    "The Australian Age of Dinosaurs Museum has a massive collection of dinosaur fossils awaiting preparation and the number of specimens collected is easily outpacing the number being prepared by volunteers and staff in our Laboratory," Mr Elliott said. "The Museum already has the world's largest collection of bones from Australia's biggest dinosaurs and there is enough new material to keep us working for several decades."

    The paper naming the new dinosaur was published in >Scientific Reports.

    Source: Australian Age of Dinosaurs Museum of Natural History [October 20, 2016]

  • Palaeontology: Fossil of 425-million-year-old parasite found intact with its host

    Palaeontology: Fossil of 425-million-year-old parasite found intact with its host

    An international team of scientists led by the University of Leicester has discovered a new species of fossil in England -- and identified it as an ancient parasitic intruder.

    Fossil of 425-million-year-old parasite found intact with its host
    Two pentastomids (in orange) attached externally to the ostracod; 
    one of the pentastomids; the ostracod with its shell removed, showing the
     external pentastomids and a pentastomid near the eggs of the ostracod
     [Credit: Siveter, Briggs, Siveter and Sutton]

    The fossil species found in 425-million year old rocks in Herefordshire, in the Welsh borderland, is described as 'exceptionally well preserved.' The specimens range from about 1 to 4 millimeters long.

    The fossil species -- a 'tongue worm', which has a worm-like body and a head and two pairs of limbs -- is actually a parasite whose representatives today live internally in the respiratory system of a host, which it enters when it is eaten.

    The new fossil, which was originally entirely soft-bodied, is the first fossil tongue worm species to be found associated with its host, which in this case is a species of ostracod -- a group of micro-arthropods (crabs, spiders and insects are also arthropods) with two shells that are joined at a hinge.

    Professor David Siveter, of the Department of Geology at the University of Leicester made the discovery working alongside researchers from the Universities of Oxford, Imperial College London and Yale, USA. Their research is published in the journal Current Biology and was supported by The Natural Environmental Research Council, together with the Leverhulme Trust, the John Fell Oxford University Press (OUP) Research Fund and Yale Peabody Museum of Natural History.

    Professor Siveter said: "This discovery is important not only because examples of parasites are exceptionally rare in the fossil record, but also because the possible host of fossil tongue worms -- and the origin of the lifestyle of tongue worms -- has been the subject of much debate.

    "This discovery affirms that tongue worms were 'external' parasites on marine invertebrate animals at least 425 million years ago; it also suggests that tongue worms likely found their way into land-based environments and associated hosts in parallel with the movement of vertebrates onto the land by some 125 million years later."

    Professor Siveter said tongue worms -- technically termed pentastomids -- are in fact not worms at all; they are an unusual group of tiny and widespread parasitic arthropods. Their fossils are exceptionally rare and until now are known only from a handful of isolated juvenile specimens.

    Today they are known from about 140 species, nearly all of which are parasitic on vertebrate animals, particularly reptiles and including humans. Some of the fossil tongue worm specimens occur inside the shell, near the eggs of the ostracod; others are attached to the external surface of its shell, a unique position for any fossil or living tongue worm.

    Professor Siveter added: "The tongue worm and its host lived in a sea that 425 million years ago -- during the Silurian period of geological time -- covered much of southern Britain, which was positioned then in warm southerly subtropical latitudes. The animals died and were preserved when a volcanic ash rained down upon them. The new species has been named Invavita piratica, which means an 'ancient intruder' and 'piracy', referring to its parasitic lifestyle in the sea."

    The fossils have been reconstructed as virtual fossils by 3D computer modelling.

    Source: University of Leicester [May 21, 2015]

  • Palaeontology: Fossil bee nests provide clues about the environment in which Australopithecus africanus lived

    Palaeontology: Fossil bee nests provide clues about the environment in which Australopithecus africanus lived

    Analysis of the first fossil bee nest from the Plio-Pleistocene of South Africa suggests that the human ancestor Australopithecus africanus lived in a dry savannah environment, according a study published in the >open-access journal PLOS ONE by Jennifer Parker from University College London, United Kingdom, and colleagues.

    Fossil bee nests provide clues about the environment in which Australopithecus africanus lived
    Photographs of each of the Individual Pieces of Extracted Nest [CreditJennifer F. Parker et al./PLOS ONE (2016)]

    Little paleoecological information is available for the site in South Africa where the first Au. africanus fossil—the 'Taung Child'—was discovered. However, insect-related fossils, abundant at the discovery site, can yield insights into the paleoenvironment. Bees, for example, tend to build characteristic nests in characteristic conditions. Parker and colleagues analyzed CT scans of a fossil bee nest that was discovered near the Taung Child site to determine its internal structure and thus the kinds of bees that built it.

    Fossil bee nests provide clues about the environment in which Australopithecus africanus lived
    Locality and stratigraphy of the deposits [Credit: Jennifer F. Parker et al./PLOS ONE (2016)]

    The fossil nest was exceptionally well preserved, and the structure of its cells and tunnels suggested that it was made by a ground-nesting solitary bee. These bees typically nest on bare, light, dry soil that is exposed to the sun, which bolsters other recent evidence that Au. africanus lived in dry savannahs. Insect-related fossils are common but largely overlooked at sites where human ancestors lived, the researchers said, and their work underscores the contribution such fossils can make to understanding the environments where human ancestors lived.

    Fossil bee nests provide clues about the environment in which Australopithecus africanus lived
    Three different individual cells. (A) and (B) have been extracted from the nest, and (C) (although broken 
    in half laterally) remains in the matrix [Credit: Jennifer F. Parker et al./PLOS ONE (2016)]

    "When Raymond Dart published his description of the 'Taung Child' in 1925 he profoundly changed our understanding of human evolution," says study co-author Philip Hopley. "In the 90 years following his discovery, attention of anthropologists has moved to other African sites and specimens, and research at Taung has been hampered by the complex geology and uncertain dating. New research at Taung is helping to reconstruct the environment in which this enigmatic little hominin lived and died."

    Source: Public Library of Science [September 29, 2016]

  • Kenya: 17 million-year-old whale fossil pinpoints date of East Africa's puzzling uplift

    Kenya: 17 million-year-old whale fossil pinpoints date of East Africa's puzzling uplift

    Uplift associated with the Great Rift Valley of East Africa and the environmental changes it produced have puzzled scientists for decades because the timing and starting elevation have been poorly constrained.

    17 million-year-old whale fossil pinpoints date of East Africa's puzzling uplift
    A 17 million-year-old whale fossil stranded far inland in Kenya now sheds light on the
     timing and starting elevation of East Africa's puzzling tectonic uplift, says paleontologist 
    Louis Jacobs, Southern Methodist University, Dallas, who rediscovered the fossil 
    [Credit: Southern Methodist University]

    Now paleontologists have tapped a fossil from the most precisely dated beaked whale in the world -- and the only stranded whale ever found so far inland on the African continent -- to pinpoint for the first time a date when East Africa's mysterious elevation began.

    The 17 million-year-old fossil is from the beaked Ziphiidae whale family. It was discovered 740 kilometers inland at an elevation of 620 meters in modern Kenya's harsh desert region, said vertebrate paleontologist Louis L. Jacobs, Southern Methodist University, Dallas.

    At the time the whale was alive, it would have been swimming far inland up a river with a low gradient ranging from 24 to 37 meters over more than 600 to 900 kilometers, said Jacobs, a co-author of the study.

    The study, published in the Proceedings of the National Academy of Sciences, provides the first constraint on the start of uplift of East African terrain from near sea level.

    "The whale was stranded up river at a time when east Africa was at sea level and was covered with forest and jungle," Jacobs said. "As that part of the continent rose up, that caused the climate to become drier and drier. So over millions of years, forest gave way to grasslands. Primates evolved to adapt to grasslands and dry country. And that's when -- in human evolution -- the primates started to walk upright."

    Identified as a Turkana ziphiid, the whale would have lived in the open ocean, like its modern beaked cousins. Ziphiids, still one of the ocean's top predators, are the deepest diving air-breathing mammals alive, plunging to nearly 10,000 feet to feed, primarily on squid.

    17 million-year-old whale fossil pinpoints date of East Africa's puzzling uplift
    A map of Africa and Kenya showing where a 17-million-year-old whale fossil
     was found far inland [Credit: Wichura/PNAS]

    In contrast to most whale fossils, which have been discovered in marine rocks, Kenya's beached whale was found in river deposits, known as fluvial sediments, said Jacobs, a professor in the Roy M. Huffington Department of Earth Sciences of SMU's Dedman College of Humanities and Sciences. The ancient large Anza River flowed in a southeastward direction to the Indian Ocean. The whale, probably disoriented, swam into the river and could not change its course, continuing well inland.

    "You don't usually find whales so far inland," Jacobs said. "Many of the known beaked whale fossils are dredged by fishermen from the bottom of the sea."

    Determining ancient land elevation is very difficult, but the whale provides one near sea level.

    "It's rare to get a paleo-elevation," Jacobs said, noting only one other in East Africa, determined from a lava flow.

    Beaked whale fossil surfaced after going missing for more than 30 years

    The beaked whale fossil was discovered in 1964 by J.G. Mead in what is now the Turkana region of northwest Kenya.

    Mead, an undergraduate student at Yale University at the time, made a career at the Smithsonian Institution, from which he recently retired. Over the years, the Kenya whale fossil went missing in storage. Jacobs, who was at one time head of the Division of Paleontology for the National Museums of Kenya, spent 30 years trying to locate the fossil. His effort paid off in 2011, when he rediscovered it at Harvard University and returned it to the National Museums of Kenya.

    The fossil is only a small portion of the whale, which Mead originally estimated was 7 meters long during its life. Mead unearthed the beak portion of the skull, 2.6 feet long and 1.8 feet wide, specifically the maxillae and premaxillae, the bones that form the upper jaw and palate.

    The researchers reported their findings in "A 17 million-year-old whale constrains onset of uplift and climate change in East Africa" online at the PNAS web site.

    Modern cases of stranded whales have been recorded in the Thames River in London, swimming up a gradient of 2 meters over 70 kilometers; the Columbia River in Washington state, a gradient of 6 meters over 161 kilometers; the Sacramento River in California, a gradient of 4 meters over 133 kilometers; and the Amazon River in Brazil, a gradient of 1 meter over 1,000 kilometers.

    Source: Southern Methodist University [March 17, 2015]

  • Palaeontology: Africa’s earliest known coelacanth found in Eastern Cape

    Palaeontology: Africa’s earliest known coelacanth found in Eastern Cape

    Various specimens of Africa’s earliest coelacanth have been found in a 360 million year-old fossil estuary near Grahamstown, in South Africa’s Eastern Cape.

    Africa’s earliest known coelacanth found in Eastern Cape
    Serenichthys coelacanth holotype 
    [Credit: Wits University]

    More than 30 complete specimens of the new fossil species, Serenichthys kowiensis, were collected from the famous Late Devonian aged Waterloo Farm locality, by palaeontologist Dr Robert Gess and described by him in collaboration with Professor Michael Coates of the University of Chicago.

    Gess did the research whilst he was completing his PhD at the Evolutionary Studies Institute at the University of the Witwatersrand. An article describing the new species will be published in the in the prestigious Zoological Journal of the Linnean Society of London on Monday, 21 August.

    “Remarkably, all of the delicate whole fish impressions represent juveniles. This suggests that Serenichthys was using a shallow, waterweed-filled embayment of the estuary as a nursery, as many fish do today,” says Gess.

    The fossils come from black shales originally disturbed by road works at Waterloo Farm. These shales are the petrified compacted remains of mud, which was deposited in the quiet reaches of an estuary not unlike some of those along the Eastern Cape coast today.

    “This earliest known record of a coelacanth nursery foreshadows a much younger counterpart, known from the 300 million year old Mazon Creek beds of Illinois in the United States,” says Gess.

    “This glimpse into the early life history of ancient coelacanths raises further questions about the life history of the modern coelacanth, Latimeria, which is known to bear live young, but whether they, too, are clustered in nurseries remains unknown,” explains Coates.

    360 million years ago, Africa was part of the southern supercontinent Gondwana, made up of Africa, India, Australia, Antarctica and South America. At that time, the rocks of Waterloo Farm were forming along the shores of the semi-enclosed Agulhas Sea, not far from the South Pole.

    Africa’s earliest known coelacanth found in Eastern Cape
    Reconstruction of Serenichthys kowiensis. Scale bar – 5 mm. 
    [Credit: Wits University]

    Gess originally identified coelacanth remains from the locality whilst carrying out excavations at Waterloo Farm in the mid-1990s under the supervision of Dr Norton Hiller, of the Rhodes University Geology Department. These fossils were not, however, well enough preserved to be reconstructed and described. His painstaking excavation of tons of shale salvaged during subsequent roadworks has now shed light on dozens more specimens, a few of which are preserved in exquisite detail.

    These were prepared under a microscope and have allowed the species to be reconstructed in minute detail. They prove to be a new genus and species.

    Coelacanths are believed to have arisen during the Devonian Period (about 419.2 ± 3.2 million years ago), however only five species of reconstructable Devonian coelacanths have previously been described, in addition to a number of very fragmentary remains. None of these came from Africa, but rather from North America, Europe, China and Australia. The new species gives important additional information on the early evolution of coelacanths.

    “According to our evolutionary analysis (conducted by Gess and Coates), it is the Devonian species that most closely resembles the line leading to modern coelacanths,” says Gess.

    The new species was discovered a mere 100km from the mouth of the Chalumna River, off which the type specimen of Latimeria chalumnae (the first discovered modern coelacanth) was caught in 1938.

    Furthermore, the Geology Department at Rhodes, where Gess was based when he found his first fossil coelacanth, is on the site of the former Chemistry Department where Latimeria was first described. In keeping with the naming of its living relative (after an Eastern Cape river), the species name of the new fossil form, kowiensis, is after the Kowie River which rises among the hills where it was found, and the genus name, Serenichthys, honours Serena Gess, who provided land for the storage of more than 70 tons of black shale rescued from roadworks for ongoing research – in which all the new material was found.

    All specimens have been deposited in the palaeontological collection of the Albany Natural History Museum, in Grahamstown, Eastern Cape Province, South Africa.

    Source: University of the Witwatersrand [September 21, 2015]

  • Fossils: Unearthed: The cannibal sharks of a forgotten age

    Fossils: Unearthed: The cannibal sharks of a forgotten age

    Scientists have discovered macabre fossil evidence suggesting that 300 million-year-old sharks ate their own young, as fossil poop of adult Orthacanthus sharks contained the tiny teeth of juveniles. These fearsome marine predators used protected coastal lagoons to rear their babies, but it seems they also resorted to cannibalising them when other food sources became scarce.

    Unearthed: The cannibal sharks of a forgotten age
    Sketch of Orthacanthus, the tri-cuspid tooth of Orthacanthus and a thin section of an Orthacanthus coprolite 
    showing teeth within the black box [Credit: University of Bristol]

    Three hundred million years ago, Europe and North America lay on the equator and were covered by steamy jungles (the remains of which are now compacted into coal seams). The top predators of these so-called "Coal Forests" were not land animals, but huge sharks that hunted in the oily waters of coastal swamps.

    The fossil evidence for shark cannibalism comes from distinctive spiral-shaped coprolites (fossil poop) found in the Minto Coalfield of New Brunswick, Canada. The poop is known to have been excreted by Orthacanthus because this shark had a special corkscrew rectum that makes identification easy. The poop is packed full of the teeth of juvenile Orthacanthus, confirming that these sharks fed on their own babies. This is called "fillial cannibalism".

    PhD candidate in the School of Natural Sciences, Trinity College Dublin, Aodhan O Gogain, made the extraordinary discovery. His findings have just been >published in the journal Palaeontology. He said: "Orthacanthus was a three-metre-long xenacanth shark with a dorsal spine, an eel-like body, and tricusped teeth. There is already evidence from fossilised stomach contents that ancient sharks like Orthacanthus preyed on amphibians and other fish, but this is the first evidence that these sharks also ate the young of their own species."

    Professor Mike Benton, University of Bristol, is a co-author of the study. He said: "As palaeontologists cannot observe predator-prey relationships directly in the way that a zoologist can, they have to use other methods to interpret ancient food webs. One method is by probing the contents of coprolites [fossil poop] as we have done here."

    Dr Howard Falcon-Lang, Royal Holloway University of London is another co-author. He said: "We don't know why Orthacanthus resorted to eating its own young. However, the Carboniferous Period was a time when marine fishes were starting to colonise freshwater swamps in large numbers. It's possible that Orthacanthus used inland waterways as protected nurseries to rear its babies, but then consumed them as food when other resources became scarce."

    Aodhan O Gogain added: "Orthacanthus was probably a bit like the modern day bull shark, in that it was able to migrate backwards and forwards between coastal swamps and shallow seas. This unusual ecological adaptation may have played an important role in the colonisation of inland freshwater environments."

    The Minto Coalfield in Canada, where the fossils were discovered, is of considerable historical importance, being the first place in North America where settlers mined coal in the early 17th Century.

    Source: University of Bristol [August 11, 2016]

  • Fossils: Ancient DNA traces extinct Caribbean 'Island Murderer' back to the dawn of mammals

    Fossils: Ancient DNA traces extinct Caribbean 'Island Murderer' back to the dawn of mammals

    From skeletal remains found among ancient owl pellets, a team of scientists has recovered the first ancient DNA of the extinct West Indian mammal Nesophontes, meaning "island murder." They traced its evolutionary history back to the dawn of mammals 70 million years ago.

    Ancient DNA traces extinct Caribbean 'Island Murderer' back to the dawn of mammals
    The Solenodon taxa is the closest living relative to the extinct Nesophontes 
    [Credit: Natural History Museum, London UK]

    The authors, including Selina Brace, Jessica Thomas, Ian Barnes et al., published their findings in the advanced online edition of >Molecular Biology and Evolution.

    The insect-eating creature existed in the Caribbean islands until the 16th century when, perhaps, they were outcompeted as the first Spanish ships arrived—-introducing rats as stowaways. "Nesophontes was just one of the dozens of mammals that went extinct in the Caribbean during recent times," said Professor Ian Barnes, Research Leader at London's Natural History Museum.

    Ancient DNA traces extinct Caribbean 'Island Murderer' back to the dawn of mammals
    The relationship of Nesophontes to other mammals [Credit: Natural History Museum, London UK]

    Scientists used a 750-year-old specimen to generate many thousands of base pairs of DNA sequence data. This allowed the research team to uncover its evolutionary origins and finally resolve the relationships between its closest relatives, the insectivores, a group including shrews, hedgehogs and moles. Phylogenetic and divergence time scenarios clearly demonstrate that Nesophontes is a deeply distinct sister group to another group of living native Caribbean insectivores, the solenodons. The time of the split between these two correlates with an era when the northern Caribbean was formed of volcanic islands, well before the origins of the islands we see today.

    Obtaining DNA from tropical fossils is notoriously difficult, and the team made use of the latest developments in ancient DNA technology to conduct the study.

    Ancient DNA traces extinct Caribbean 'Island Murderer' back to the dawn of mammals
    Nesophontes sample used in the investigation, recovered from skeletal remains in owl pellets. (a) Map of the Carribean
     and Hispaniola (b) where the sample was recovered, and a skull from the collection locality (c) 
    [Credit: Natural History Museum, London UK]

    "Once we'd dealt with the tiny size of the bone samples, the highly degraded state of the DNA, and the lack of any similar genomes to compare to, the analysis was a piece of cake," said Natural History Museum scientist Dr. Selina Brace.

    The findings will be of considerable interest for evolutionary biologists studying mammalian biogeography, and the significant role that humans may have played in a recent extinction.

    Source: Oxford University Press [September 13, 2016]

  • Fossils: Cold snap: Climate cooling and sea-level changes caused crocodilian retreat

    Fossils: Cold snap: Climate cooling and sea-level changes caused crocodilian retreat

    Fluctuating sea levels and global cooling caused a significant decline in the number of crocodylian species over millions of years, according to new research.

    Cold snap: Climate cooling and sea-level changes caused crocodilian retreat
    Image of Sarcosuchus [Credit: Imperial College London 
    and Robert Nicholls]

    Crocodylians include present-day species of crocodiles, alligators, caimans and gavials and their extinct ancestors. Crocodylians first appeared in the Late Cretaceous period, approximately 85 million years ago, and the 250 million year fossil record of their extinct relatives reveals a diverse evolutionary history.

    Extinct crocodylians and their relatives came in all shapes and sizes, including giant land-based creatures such as Sarcosuchus, which reached around 12 metres in length and weighed up to eight metric tonnes. Crocodylians also roamed the ocean -- for example, thalattosuchians were equipped with flippers and shark-like tails to make them more agile in the sea.

    Many crocodylians survived the mass extinction that wiped out almost all of the dinosaurs 66 million years ago, but only 23 species survive today, six of which are classified by the International Union for Conservation of Nature as critically endangered and a further four classified as either endangered or vulnerable.

    In a new study published in Nature Communications, researchers from Imperial College London, the University of Oxford, the Smithsonian Institution and the University of Birmingham compiled a dataset of the entire known fossil record of crocodylians and their extinct relatives and analysed data about Earth's ancient climate. They wanted to explore how the group responded to past shifts in climate, to better understand how the reptiles may cope in the future.

    Crocodylians are ectotherms, meaning they rely on external heat sources from the environment such as the Sun. The researchers conclude that at higher latitudes in areas we now know as Europe and America, declining temperatures had a major impact on crocodylians and their relatives.

    At lower latitudes the decline of crocodylians was caused by areas on many continents becoming increasingly arid. For example, in Africa around ten million years ago, the Sahara desert was forming, replacing the vast lush wetlands in which crocodylians thrived. In South America, the rise of the Andes Mountains led to the loss of a proto-Amazonian mega wetland habitat that crocodylians lived in around five million years ago.

    Marine species of crocodylians were once widespread across the oceans. The team found that fluctuations in sea levels exerted the main control over the diversity of these creatures. For example, at times when the sea level was higher it created greater diversity because it increased the size of the continental shelf, providing the right conditions near the coast for them and their prey to thrive.

    Interestingly, the Cretaceous-Paleogene mass extinction event, which wiped out many other creatures on Earth nearly 66 million years ago including nearly all of the dinosaurs, had positive outcomes for the crocodylians and their extinct relatives. The team found that while several groups did go extinct, the surviving groups rapidly radiated out of their usual habitats to take advantage of territories that were now uninhabited.

    In the future, the team suggest that a warming world caused by global climate change may favour crocodylian diversification again, but human activity will continue to have a major impact on their habitats.

    Dr Philip Mannion, joint lead author from the Department of Earth Science and Engineering at Imperial College London, said: "Crocodylians are known by some as living fossils because they've been around since the time of the dinosaurs. Millions of years ago these creatures and their now extinct relatives thrived in a range of environments that ranged from the tropics, to northern latitudes and even deep in the ocean. However, all this changed because of changes in the climate, and crocodylians retreated to the warmer parts of the world. While they have a fearsome reputation, these creatures are vulnerable and looking back in time we've been able to determine what environmental factors had the greatest impact on them. This may help us to determine how they will cope with future changes."

    The next step for the researchers will be for them to look at similar patterns in other fossil groups with long histories, such as mammals and birds to determine how past climate influenced them.

    Source: Imperial College London [September 24, 2015]

  • Namibia: Study provides strongest evidence oxygen levels were key to early animal evolution

    Namibia: Study provides strongest evidence oxygen levels were key to early animal evolution

    It has long puzzled scientists why, after 3 billion years of nothing more complex than algae, complex animals suddenly started to appear on Earth. Now, a team of researchers has put forward some of the strongest evidence yet to support the hypothesis that high levels of oxygen in the oceans were crucial for the emergence of skeletal animals 550 million years ago.

    Study provides strongest evidence oxygen levels were key to early animal evolution
    Rosalie Tostevin in Namibia [Credit: Fred Bowyer]

    The new study is the first to distinguish between bodies of water with low and high levels of oxygen. It shows that poorly oxygenated waters did not support the complex life that evolved immediately prior to the Cambrian period, suggesting the presence of oxygen was a key factor in the appearance of these animals.

    Lead author Dr Rosalie Tostevin completed the study analyses as part of her PhD with UCL Earth Sciences, and is now in the Department of Earth Sciences at Oxford University. She said: 'The question of why it took so long for complex animal life to appear on Earth has puzzled scientists for a long time. One argument has been that evolution simply doesn't happen very quickly, but another popular hypothesis suggests that a rise in the level of oxygen in the oceans gave simple life-forms the fuel they needed to evolve skeletons, mobility and other typical features of modern animals.

    'Although there is geochemical evidence for a rise in oxygen in the oceans around the time of the appearance of more complex animals, it has been really difficult to prove a causal link. By teasing apart waters with high and low levels of oxygen, and demonstrating that early skeletal animals were restricted to well-oxygenated waters, we have provided strong evidence that the availability of oxygen was a key requirement for the development of these animals. However, these well-oxygenated environments may have been in short supply, limiting habitat space in the ocean for the earliest animals.'

    Study provides strongest evidence oxygen levels were key to early animal evolution
    Cloudina fossils [Credit: Rachel Wood]

    The team, which included other geochemists, palaeoecologists and geologists from UCL and the universities of Edinburgh, Leeds and Cambridge, as well as the Geological Survey of Namibia, analysed the chemical elemental composition of rock samples from the ancient seafloor in the Nama Group - a group of extremely well-preserved rocks in Namibia that are abundant with fossils of early Cloudina, Namacalathus and Namapoikia animals.

    The researchers found that levels of elements such as cerium and iron detected in the rocks showed that low-oxygen conditions occurred between well-oxygenated surface waters and fully 'anoxic' deep waters. Although abundant in well-oxygenated environments, early skeletal animals did not occupy oxygen-impoverished regions of the shelf, demonstrating that oxygen availability (probably >10 micromolar) was a key requirement for the development of early animal-based ecosystems.

    Professor Graham Shields-Zhou (UCL Earth Sciences), one of the co-authors and Dr Tostevin's PhD supervisor, said: 'We honed in on the last 10 million years of the Proterozoic Eon as the interval of Earth's history when today's major animal groups first grew shells and churned up the sediment, and found that oxygen levels were important to the relationship between environmental conditions and the early development of animals.'

    The research, based on fieldwork carried out in the Nama Group in Namibia, is published in the >journal Nature Communications.

    Source: University College London [September 23, 2016]

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