WFS

Formation of sedimentary layers of white clay, Tamilnadu, India

Fossil site for wood fossils, Tamilnadu, India

Fossil site in Kerala, India

Fossil wood park maintained by geological survey of India at Tamilnadu

Cretaceous fossil sites india

Fossils in rack:-Cyad

Fossils in rack:-echiniderms

Fossils in rack:-Rastellum sp

Pre-historic seabed, Cretaceous period

Plate tectonics cannot explain dynamics of Earth and crust formation more than three billion years ago

November 10th, 2016

Riffin

The current theory of continental drift provides a good model for understanding terrestrial processes through history. However, while plate tectonics is able to successfully shed light on processes up to 3 billion years ago, the theory isn’t sufficient in explaining the dynamics of Earth and crust formation before that point and through to the earliest formation of planet, some 4.6 billion years ago. This is the conclusion of Tomas Naæraa of the Nordic Center for Earth Evolution at the Natural History Museum of Denmark, a part of the University of Copenhagen. His new doctoral dissertation has just been published by the journal Nature.

“Using radiometric dating, one can observe that Earth’s oldest continents were created in geodynamic environments which were markedly different than current environments characterised by plate tectonics. Therefore, plate tectonics as we know it today is not a good model for understanding the processes at play during the earliest episodes of Earths’s history, those beyond 3 billion years ago. There was another crust dynamic and crust formation that occurred under other processes,” explains Tomas Næraa, who has been a PhD student at the Natural History Museum of Denmark and the Geological Survey of Denmark and Greenland — GEUS.

“Plate tectonics theory can be applied to about 3 billion years of the Earth’s history. However, the Earth is older, up to 4.567 billion years old. We can now demonstrate that there has been a significant shift in the Earth’s dynamics. Thus, the Earth, under the first third of its history, developed under conditions other than what can be explained using the plate tectonics model,” explains Tomas Næraa.
Credit: Image courtesy of University of Copenhagen

Plate tectonics is a theory of continental drift and sea floor spreading. A wide range of phenomena from volcanism, earthquakes and undersea earthquakes (and pursuant tsunamis) to variations in climate and species development on Earth can be explained by the plate tectonics model, globally recognized during the 1960’s. Tomas Næraa can now demonstrate that the half-century old model no longer suffices.

“Plate tectonics theory can be applied to about 3 billion years of the Earth’s history. However, the Earth is older, up to 4.567 billion years old. We can now demonstrate that there has been a significant shift in the Earth’s dynamics. Thus, the Earth, under the first third of its history, developed under conditions other than what can be explained using the plate tectonics model,” explains Tomas Næraa. Tomas is currently employed as a project researcher at GEUS.

Central research topic for 30 years

Since 2006, the 40-year-old Tomas Næraa has conducted studies of rocks sourced in the 3.85 billion year-old bedrock of the Nuuk region in West Greenland. Using isotopes of the element hafnium (Hf), he has managed to shed light upon a research topic that has puzzled geologists around the world for 30 years. Næraa’s instructor, Professor Minik Rosing of the Natural History Museum of Denmark considers Næraa’s dissertation a seminal work:

“We have come to understand the context of the Earth’s and continent’s origins in an entirely new way. Climate and nutrient cycles which nourish all terrestrial organisms are driven by plate tectonics. So, if the Earth’s crust formation was controlled and initiated by other factors, we need to find out what controlled climate and the environments in which life began and evolved 4 billion years ago. This fundamental understanding can be of great significance for the understanding of future climate change,” says Minik Rosing, who adds that: “An enormous job waits ahead, and Næraas’ dissertation is an epochal step.”

Journal Reference:

T. Næraa, A. Scherstén, M. T. Rosing, A. I. S. Kemp, J. E. Hoffmann, T. F. Kokfelt, M. J. Whitehouse. Hafnium isotope evidence for a transition in the dynamics of continental growth 3.2 Gyr ago. Nature, 2012; 485 (7400): 627 DOI: 10.1038/nature11140

University of Copenhagen. “Plate tectonics cannot explain dynamics of Earth and crust formation more than three billion years ago.” ScienceDaily. ScienceDaily, 1 June 2012. <www.sciencedaily.com/releases/2012/06/120601120606.htm>.
Key: WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

WFS News: Fossil clues to aftermath of dinosaur asteroid strike

November 7th, 2016

Riffin

Rapid recovery of Patagonian plant–insect associations after the end-Cretaceous extinction

Michael P. Donovan,, Ari Iglesias,, Peter Wilf,, Conrad C. Labandeira, & N. Rubén Cúneo

The Southern Hemisphere may have provided biodiversity refugia after the Cretaceous/Palaeogene (K/Pg) mass extinction. However, few extinction and recovery studies have been conducted in the terrestrial realm using well-dated macrofossil sites that span the latest Cretaceous (late Maastrichtian) and early Palaeocene (Danian) outside western interior North America (WINA). Here, we analyse insect-feeding damage on 3,646 fossil leaves from the latest Maastrichtian and three time slices of the Danian in Chubut, Patagonia, Argentina (palaeolatitude approximately 50° S). We test the southern refugial hypothesis and the broader hypothesis that the extinction and recovery of insect herbivores, a central component of terrestrial food webs, differed substantially from WINA at locations far south of the Chicxulub impact structure in Mexico. We find greater insect-damage diversity in Patagonia than in WINA during both the Maastrichtian and Danian, indicating a previously unknown insect richness. As in WINA, the total diversity of Patagonian insect damage decreased from the Cretaceous to the Palaeocene, but recovery to pre-extinction levels occurred within approximately 4 Myr compared with approximately 9 Myr in WINA. As for WINA, there is no convincing evidence for survival of any of the diverse Cretaceous leaf miners in Patagonia, indicating a severe K/Pg extinction of host-specialized insects and no refugium. However, a striking difference from WINA is that diverse, novel leaf mines are present at all Danian sites, demonstrating a considerably more rapid recovery of specialized herbivores and terrestrial food webs. Our results support the emerging idea of large-scale geographic heterogeneity in extinction and recovery from the end-Cretaceous catastrophe.

a–l, Latest Cretaceous samples from the Lefipán Formation (a–c), and early Palaeocene samples8 from the Salamanca (d–i) and Peñas Coloradas (j–l) formations. a, Multiple, overlapping blotch mines containing centralized frass (DT299) on leaf morphotype LEF28 (LefW; MPEF-Pb 4776). b, Spheroidal galls with striated surfaces (DT303) on LEF2 (LefE; MPEF-Pb 4259). c, Margin feeding with thickened reaction tissue (DT12) on LEF23 (LefL; MPEF-Pb 4758). d, Serpentine mine with spheroidal terminal chamber (DT300) on Cissites patagonica (PL1; MPEF-Pb 6557). e, Elliptical gall positioned on the primary vein at the intersection with secondary veins (DT84) on Laurophyllum piatnitzkyi (PL1; MPEF-Pb 6555). f, Row of parallel-sided holes near the leaf margin (DT64) on Dryophyllum australis (PL1; MPEF-Pb 6560). g, Spheroidal galls with distinct outer rims positioned on the primary vein (DT117) of Cissites patagonica (PL2; MPEF-Pb 6567). h, Concentric rings of piercing and sucking marks surrounded by dark reaction tissue (DT118) on SA19 (PL2; MPEF-Pb 4072). i, Hole feeding surrounded by a wide rim of blotched reaction tissue (DT113) on SA43 (PL2; MPEF-Pb 6561). j, Serpentine mines that transition to blotch mines with internal, intestiniform trails (DT301) on Fagophyllum duseni (LF; MPEF-Pb 6547). k, Elongate, curvilinear patches of skeletonized tissue (DT20) on SA70 (LF; MPEF-Pb 6549). l, Deeply incised margin feeding damage (DT15) on Dryophyllum australis (LF; MPEF-Pb 6546). DT, damage type27 (new DTs defined in Supplementary Discussion).

Palaeontological evidence from both continental and marine deposits suggests that the Southern Hemisphere may have harboured biodiversity refugia in the wake of the bolide impact at Chicxulub, Mexico, 66.0 Myr ago (Ma)^1,2,3,4. The extinction rate of Southern Hemisphere nannoplankton was lower than that of their Northern Hemisphere counterparts, and their populations recovered nearly immediately². Nominally Mesozoic plant groups, including corystosperms and bennettitaleans, survived until at least the Palaeogene in Australia^1,5. Palynological data from New Zealand revealed a sudden but short-lived disturbance, with low overall extinction rates^6,7. In Patagonia, Argentina, palynomorphs from the latest Maastrichtian–early Danian Lefipán Formation exhibited low extinction, followed by the reappearances of Cretaceous pollen types³. Early Danian macrofloras from the Salamanca Formation in Patagonia are more diverse than comparable North American Palaeocene floras^8,9,10. A number of surviving lineages from other plant³ and vertebrate^11,12groups have also been identified, especially in Patagonia⁴, although marine invertebrate faunas in Antarctica underwent severe extinction¹³. K/Pg boundary sections in New Zealand have provided important insights into the response of terrestrial ecosystems^6,7,14,15,16, but until recently there has not been a series of well-dated, heavily sampled continental macrofloral localities anywhere in the Southern Hemisphere that spans both the terminal Cretaceous and earliest Palaeogene.

Plant–insect interactions are fundamental components of terrestrial food webs, and their sensitivity to major environmental perturbations is well known from deep time as well as the modern world^17,18,19,20. The diversity of insect-feeding damage on extant leaves in two tropical rainforests is positively correlated with the richness of insects that caused the damage, supporting the widespread use of insect damage on fossil leaves as a proxy for herbivorous insect diversity when suitable insect body fossils are absent²¹. In North Dakota, USA, insect-damage diversity on fossil leaves, especially specialized feeding such as mining and galling, declined considerably across the K/Pg boundary and remained low throughout WINA before increasing with the latest Palaeocene warming, approximately 9 Myr after the K/Pg boundary^17,18,20. The only exception to this pattern is the early Palaeocene (about 65 Ma) Mexican Hat locality in south-eastern Montana, USA, which has typical low-diversity flora but anomalously high insect damage diversity for the time; this pattern is attributed to a short-lived interval of decoupled plant and insect diversity following the K/Pg mass extinction^17,20.

Much less is known about the extinction and recovery of insect herbivores outside WINA. Late Palaeocene floras from Colombia are associated with low richness of plants and specialized insect-damage diversity as in Palaeocene WINA²², contrasting with high plant and insect-damage diversity on middle Palaeocene floras from France²³ and Spitsbergen²⁴. However, until now, no studies have investigated changes in insect-damage diversity based on terminal Cretaceous and early Palaeocene leaf floras from any non-WINA study area.

Full Text: http://www.nature.com/articles/s41559-016-0012

WFS,World Fossil Society,Riffin T Sajeev,Russel T sajeev

Atom-by-atom growth chart for shells helps decode past climate

October 31st, 2016

Riffin

For the first time scientists can see how the shells of tiny marine organisms grow atom-by-atom, a new study reports. The advance provides new insights into the mechanisms of biomineralization and will improve our understanding of environmental change in Earth’s past.

Led by researchers from the University of California, Davis and the University of Washington, with key support from the U.S. Department of Energy’s Pacific Northwest National Laboratory, the team examined an organic-mineral interface where the first calcium carbonate crystals start to appear in the shells of foraminifera, a type of plankton.

“We’ve gotten the first glimpse of the biological event horizon,” said Howard Spero, a study co-author and UC Davis geochemistry professor. The findings were published in theProceedings of the National Academy of Sciences.

Foraminifera’s Final Frontier

The researchers zoomed into shells at the atomic level to better understand how growth processes may influence the levels of trace impurities in shells. The team looked at a key stage — the interaction between the biological ‘template’ and the initiation of shell growth. The scientists produced an atom-scale map of the chemistry at this crucial interface in the foraminifera Orbulina universa. This is the first-ever measurement of the chemistry of a calcium carbonate biomineralization template, Spero said.

Among the new findings are elevated levels of sodium and magnesium in the organic layer. This is surprising because the two elements are not considered important architects in building shells, said lead study author Oscar Branson, a former postdoctoral researcher at UC Davis who is now at the Australian National University in Canberra. Also, the greater concentrations of magnesium and sodium in the organic template may need to be considered when investigating past climate with foraminifera shells.

Calibrating Earth’s Climate

Most of what we know about past climate (beyond ice core records) comes from chemical analyses of shells made by the tiny, one-celled creatures called foraminifera, or “forams.” When forams die, their shells sink and are preserved in seafloor mud. The chemistry preserved in ancient shells chronicles climate change on Earth, an archive that stretches back nearly 200 million years.

The calcium carbonate shells incorporate elements from seawater — such as calcium, magnesium and sodium — as the shells grow. The amount of trace impurities in a shell depends on both the surrounding environmental conditions and how the shells are made. For example, the more magnesium a shell has, the warmer the ocean was where that shell grew.

Foraminifera are marine organisms whose shells, buried in marine sediments, provide a record of past climate stretching back 200 million years. A new study by UC Davis, University of Washington and Pacific Northwest National Lab applies material science techniques to understand how foraminifera build their shells, and may help improve our understanding of this climate record. Image shows the foraminiferan Orbulina universa.
Credit: Howard Spero, UC Davis

“Finding out how much magnesium there is in a shell can allow us to find out the temperature of seawater going back up to 150 million years,” Branson said.

But magnesium levels also vary within a shell, because of nanometer-scale growth bands. Each band is one day’s growth (similar to the seasonal variations in tree rings). Branson said considerable gaps persist in understanding what exactly causes the daily bands in the shells.

“We know that shell formation processes are important for shell chemistry, but we don’t know much about these processes or how they might have changed through time,” he said. “This adds considerable uncertainty to climate reconstructions.”

Atomic Maps

The researchers used two cutting-edge techniques: Time-of-Flight Secondary Ionization Mass Spectrometry (ToF-SIMS) and Laser-Assisted Atom Probe Tomography (APT). ToF-SIMS is a two-dimensional chemical mapping technique which shows the elemental composition of the surface of a polished sample. The technique was developed for the elemental analysis of complex polymer materials, and is just starting to be applied to natural samples like shells.

APT is an atomic-scale three-dimensional mapping technique, developed for looking at internal structures in advanced alloys, silicon chips and superconductors. The APT imaging was performed at the Environmental Molecular Sciences Laboratory, a U.S. Department of Energy Office of Science User Facility at the Pacific Northwest National Laboratory.

University of California – Davis. “Atom-by-atom growth chart for shells helps decode past climate.” ScienceDaily. ScienceDaily, 24 October 2016. <www.sciencedaily.com/releases/2016/10/161024170634.htm>.

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Fossilized dinosaur brain tissue identified for the first time : WFS News

October 28th, 2016

Riffin

Researchers have identified the first known example of fossilised brain tissue in a dinosaur from Sussex. The tissues resemble those seen in modern crocodiles and birds.

An unassuming brown pebble, found more than a decade ago by a fossil hunter in Sussex, has been confirmed as the first example of fossilised brain tissue from a dinosaur.

The fossil, most likely from a species closely related toIguanodon, displays distinct similarities to the brains of modern-day crocodiles and birds. Meninges — the tough tissues surrounding the actual brain — as well as tiny capillaries and portions of adjacent cortical tissues have been preserved as mineralised ‘ghosts’.

The results are reported in a Special Publication of the Geological Society of London, published in tribute to Professor Martin Brasier of the University of Oxford, who died in 2014. Brasier and Dr David Norman from the University of Cambridge co-ordinated the research into this particular fossil during the years prior to Brasier’s untimely death in a road traffic accident.

The fossilised brain, found by fossil hunter Jamie Hiscocks near Bexhill in Sussex in 2004, is most likely from a species similar toIguanodon: a large herbivorous dinosaur that lived during the Early Cretaceous Period, about 133 million years ago.

Finding fossilised soft tissue, especially brain tissue, is very rare, which makes understanding the evolutionary history of such tissue difficult. “The chances of preserving brain tissue are incredibly small, so the discovery of this specimen is astonishing,” said co-author Dr Alex Liu of Cambridge’s Department of Earth Sciences, who was one of Brasier’s PhD students in Oxford at the time that studies of the fossil began.

According to the researchers, the reason this particular piece of brain tissue has been so well-preserved is that the dinosaur’s brain was essentially ‘pickled’ in a highly acidic and low-oxygen body of water — similar to a bog or swamp — shortly after its death. This allowed the soft tissues to become mineralised before they decayed away completely, so that they could be preserved.

“What we think happened is that this particular dinosaur died in or near a body of water, and its head ended up partially buried in the sediment at the bottom,” said Norman. “Since the water had little oxygen and was very acidic, the soft tissues of the brain were likely preserved and cast before the rest of its body was buried in the sediment.”

Image of specimen. See: https://www.youtube.com/watch?v=1T5_NlRs-5o Credit: Jamie Hiscocks

Working with colleagues from the University of Western Australia, the researchers used scanning electron microscope (SEM) techniques in order to identify the tough membranes, or meninges, that surrounded the brain itself, as well as strands of collagen and blood vessels. Structures that could represent tissues from the brain cortex (its outer layer of neural tissue), interwoven with delicate capillaries, also appear to be present. The structure of the fossilised brain, and in particular that of the meninges, shows similarities with the brains of modern-day descendants of dinosaurs, namely birds and crocodiles.

In typical reptiles, the brain has the shape of a sausage, surrounded by a dense region of blood vessels and thin-walled vascular chambers (sinuses) that serve as a blood drainage system. The brain itself only takes up about half of the space within the cranial cavity.

In contrast, the tissue in the fossilised brain appears to have been pressed directly against the skull, raising the possibility that some dinosaurs had large brains which filled much more of the cranial cavity. However, the researchers caution against drawing any conclusions about the intelligence of dinosaurs from this particular fossil, and say that it is most likely that during death and burial the head of this dinosaur became overturned, so that as the brain decayed, gravity caused it to collapse and become pressed against the bony roof of the cavity.

“As we can’t see the lobes of the brain itself, we can’t say for sure how big this dinosaur’s brain was,” said Norman. “Of course, it’s entirely possible that dinosaurs had bigger brains than we give them credit for, but we can’t tell from this specimen alone. What’s truly remarkable is that conditions were just right in order to allow preservation of the brain tissue — hopefully this is the first of many such discoveries.”

“I have always believed I had something special. I noticed there was something odd about the preservation, and soft tissue preservation did go through my mind. Martin realised its potential significance right at the beginning, but it wasn’t until years later that its true significance came to be realised,” said paper co-author Jamie Hiscocks, the man who discovered the specimen. “In his initial email to me, Martin asked if I’d ever heard of dinosaur brain cells being preserved in the fossil record. I knew exactly what he was getting at. I was amazed to hear this coming from a world renowned expert like him.”

The research was funded in part by the Natural Environment Research Council (NERC) and Christ’s College, Cambridge.

Citation: University of Cambridge. “Fossilized dinosaur brain tissue identified for the first time.” ScienceDaily.ScienceDaily,27

October 2016. <www.sciencedaily.com/releases/2016/10/161027175858.htm>

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Qilinyu : A Fish fossil sheds light on jaw evolution

October 24th, 2016

Riffin

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A bottom-dwelling, mud-grubbing, armoured fish that swam in tropical seas 423 million years ago is fundamentally changing the understanding of the evolution of an indisputably indispensable anatomical feature: the jaw.

Scientists have unearthed in China’s Yunnan province fossils of a primordial fish called Qilinyu rostrata that was about 30cm long and possessed the telltale bones present in modern vertebrate jaws including in people.Qilinyu was part of an extinct fish group called placoderms, clad in bony armour covering the head and much of the body and boasting jaws armed with bony plates that acted as teeth to slice and dice prey.

The discovery of another placoderm, called Qilinyu, from the same fossil bed, strengthens the evidence for a close relationship between bony fish and placoderms. Entelognathus and Qilinyu were contemporary cousins, and while they look different from one another, they are clearly intermediates between conventional placoderms and bony fish. Sharks and rays are actually an evolutionary offshoot.

Fish were Earth’s first vertebrates when they appeared more than half a billion years ago, but they were primitive and jawless, with sucker-like mouths. Placoderms were the first vertebrates with jaws, a pivotal evolutionary advance that enabled them to grasp prey, but they had no teeth. Teeth appeared for the first time in later fish.

Qilinyu had three bones, the dentary, maxilla and premaxilla, that characterise the modern vertebrate jaw seen in bony fish, amphibians, reptiles, birds and mammals, though they are absent in the cartilaginous sharks and rays.Scientists long viewed placoderms as a fascinating evolutionary dead-end. But the fossils of Qilinyu and another placoderm called Entelognathus that also possessed the three bones indicate that the elements of the modern jaw first appeared in placoderms.

Qilinyu

The maxilla and premaxilla are bones of the upper jaw. The dentary is a bone of the lower jaw.

It appears they evolved from the bony plates that placoderms used to sheer flesh in lieu of teeth, said paleontologist Per Ahlberg of Sweden’s University of Uppsala, who helped lead the study published in the journal Science.

“In us, the lower jaw is made entirely from the dentary. Most of the upper jaw is composed from the maxilla, but the bit that carries the incisor teeth is the premaxilla,” Ahlberg said.

The findings contradict the long-held notion that the modern jaw architecture evolved later, in the earliest bony fish.

Source: AAP

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Savannasaurus : New Australian sauropod

October 22nd, 2016

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@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

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.

The paper naming the new dinosaur was published on Thursday October 20 at 2pm BST (Friday October 21 at 12am AEST) inScientific Reports — an open access, online journal published by Nature.

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.

Type site map showing the approximate association of the bones . Scale bar = 1 m.

Savannasaurus elliottorum gen. et sp. nov., holotype specimen AODF 660.

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.”

“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.”

(a–e) Dorsal vertebrae (left lateral view). (f) Sacrum (ventral view). (g,h) Caudal vertebrae (left lateral view). (i) Left coracoid (lateral view). (j) Right sternal plate (ventral view). (k) Left radius (posterior view). (l) Right metacarpal III (anterior view). (m) Left astragalus (anterior view). (n) Coossified right and left pubes (anterior view). A number of ribs were preserved but have been omitted for clarity. Scale bar = 500 mm.

Savannasaurus elliottorum gen. et sp. nov., holotype specimen AODF 660.

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.”

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.”

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.”

Source: Australian Age of Dinosaurs Museum of Natural History. “New Cretaceous dinosaur from Queensland: Australian researchers shed light on global sauropod evolution.” ScienceDaily. ScienceDaily, 20 October 2016. <www.sciencedaily.com

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WFS News: How Earth’s oldest animals were fossilized

October 20th, 2016

Riffin

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The fossils are among the strangest ever found: a corkscrew-shaped tube, an eight-armed spiral, and a mysterious ropelike creature that might have engaged in the oldest known sexual reproduction among animals. They are Earth’s oldest complex organisms, dating back to 571 million years ago, and found on every continent except Antarctica. Their bizarre forms defy classification; some have been described alternately as jellyfish or worms, algae or fungi. But scientists have for years been chasing an even bigger mystery about the so-called Ediacara biota: How could these mostly soft-bodied animals be preserved in rock? Now, one team of scientists has an answer. Their research suggests that in the ancient oceans, silica—the primary compound in quartz—precipitated out of the seawater, then covered and entombed the organisms before they decayed.

“[This paper] will change our way of thinking about Ediacara-type preservation,” says James Schiffbauer, a paleontologist at the University of Missouri in Columbia, who was not involved in the new study. He adds that the process might not be as straightforward as scientists thought.

Aspidella, one of the most common fossils of the enigmatic Ediacara biota.

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Most fossils exist thanks to how they were buried plus the makeup of their original tissues. Bones and shells from hard-bodied creatures like dinosaurs and oysters preserve more easily than soft tissues, which decay rapidly after death. That means that most of the fossil record is biased in favor of creatures with hard components. “One of the big questions that we have in really all of paleontology … is how accurately can we read the fossil record as the history of life?” Schiffbauer says.

Before the appearance of the Ediacara biota, named for the Ediacara Hills in South Australia where scientists first found these fossils, all known life on Earth was microscopic. That’s because scientists hadn’t found any evidence of complex life until the “geologically abrupt” entrance of the Ediacaran fossils, says Yale University paleontologist Lidya Tarhan, lead author on the new study. But is this sudden explosion of the fossil record just a preservation bias or is it a sign of a massive environmental trigger for the biota’s emergence? Finding out how the group became fossils “is one of the most important steps in resolving what these organisms are and where they fall in our sense of the evolution of complex life,” she says.

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So Tarhan and her team set out to find the answer. They knew the animals lived in shallow waters on the sea floor, and that sand stirred by storms would sometimes cover the organisms. The leading theory for their preservation was that these sand grains molded around dead bodies, and the mold continued to exist long after the bodies decayed. For that to happen, “you have to cement those grains, and you have to do it early,” Tarhan says. Previous work hadn’t addressed how that cementing could have happened. But Tarhan’s team had a theory: Researchers knew the Ediacaran oceans contained far more dissolved silica than modern ones, in part because creatures that soak up silica, like sponges, were rare. So silica was the perfect candidate for a prehistoric glue.

To test their hypothesis, the team took fossils from the South Australian outback and sawed them into slivers of rock so thin that light, passing through them under a microscope, illuminated the ancient grains. “The grains are pretty much floating in what looks like a sea of cement, and they’re not very compacted,” Tarhan says. Her team confirmed that the “sea” was indeed silica. And because the grains weren’t compacted, they must have been loose as the silica cement formed around them. Finally, the team concluded that the silica-based cements were not chemically identical to the silica found in the quartz sand grains, leaving them with only one source for the cement: seawater.

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Because this style of siliceous fossilization extends long before and after the Ediacaran, the biota’s appearance—and disappearance—was not just an accident of the fossil record, Tarhan says. Instead, they must represent the group’s actual evolutionary beginning as well its ultimate extinction. “It makes a lot of sense,” says Shuhai Xiao, a geobiologist at Virginia Polytechnic Institute and State University in Blacksburg, who was also not involved in the study. “The next step is to take this model somewhere else, and to test it to see if it works” at other Ediacaran sites around the world.

Courtesy: Article By Lucas Joel in Sciencemag.org

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WFS News: Skin impressions of dinosaur found

October 18th, 2016

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Researchers from the Universitat Autònoma de Barcelona (UAB) in collaboration with the Institut Català de Paleontologia Miquel Crusafont (ICP), have discovered in Vallcebre (Barcelona) an impression fossil with the surface of the skin of a dinosaur from the Late Cretaceous, a period right before their extinction. Its characteristics make it a unique discovery in Europe.

A geological research conducted in the village of Vallcebre, near Barcelona, to study the origins of rock sediments from the Late Cretaceous period (approx. 66 million years ago) has revealed an extraordinary artefact. Researchers discovered the impression of skin scales left by a dinosaur which had lain down in the mud. During that period, the area was a muddy region corresponding to the banks of a river. As chance had it, that muddy region where the animal’s scales had left their mark was later covered with sand which, in the course of thousands of years, finally petrified to form sandstone and thus become the sedimentary rock which preserves the impression recently discovered by the researchers. The sand acted as a mould and therefore, what actually can be seen on the rock is not really the impression, but the relief of the animal’s original skin.

Dinosaur skin impression on rock.Credit: Víctor Fondevilla/UAB

The characteristics of the discovery are unique, given that the Late Cretaceous period corresponds to the moment short before dinosaurs became extinct, there are few places on Earth containing sandstone from this period, and characterising these dinosaurs is very important in order to understand how and why they disappeared. “This is the only registry of dinosaur skin from this period in all of Europe, and it corresponds to one of the most recent specimens, closer to the extinction event, in all of the world,” highlights UAB researcher Victor Fondevilla, main author of the research. “There are very few samples of fossilised skin registered, and the only sites with similar characteristics can be found in United States and Asia,” Fondevilla states. He goes on to say: “Other dinosaur skin fossils have been found in the Iberian Peninsula, in Portugal and Asturias, but they correspond to other more distant periods.”

The shape of the scales observed on the rock show a pattern characteristic of the skin of some dinosaurs: in a form of a rose with a central bump in the shape of a polygon, surrounded by five or six more bumps. However, the scales are large, too large for the typical size of carnivorous dinosaurs and hadrosaurs roaming this area 66 million years ago. “The fossil probably belongs to a large herbivore sauropod, maybe a titanosaurus, since we discovered footprints from the same species very close to the rock with the skin fossil” Fondevilla says.

In fact, two skin impressions were found, one measuring approximately 20 centimetres wide, and the other slightly smaller, measuring only 5 centimetres wide, separated by a 1.5 metre distance and probably made by the same animal. “The fact that they are impression fossils is evidence that the animal is from the sedimentary rock period, one of the last dinosaurs to live on the planet. When bones are discovered, dating is more complicated because they could have moved from the original sediment during all these millions of years,” Fondevilla states.

The finding verifies the excellent fossil registry of the Pyrenees in terms of dinosaurs living in Europe little before they became extinct throughout the planet. “The sites in Berguedà, Pallars Jussà, Alt Urgell and La Noguera, in Catalonia, have provided proof of five different groups of dinosaurs: titanosaurs, ankylosaurids, theropods, hadrosaurs and rhabdodontids,” explains Àngel Galobart, head of the Mesozoic research group at the ICP and director of the Museum of Conca Dellà in Isona. “The sites in the Pyrenees are very relevant from a scientific point of view, since they allow us to study the cause of their extinction in a geographic point far away from the impact of the meteorite,” Galobart explains.

The research, published in Geological Magazine, was led by Víctor Fondevilla and Oriol Oms from the UAB Department of Geology, in collaboration with Bernat Vila and Àngel Galobart, both from the Institut Català de Paleontologia Miquel Crusafont (ICP) and the Museum of Conca Dellà.

Citations:VÍCTOR FONDEVILLA, BERNAT VILA, ORIOL OMS, ÀNGEL GALOBART. Skin impressions of the last European dinosaurs. Geological Magazine, 2016; 1 DOI:10.1017/S0016756816000868 & Universitat Autònoma de Barcelona. “Unique skin impressions of the last dinosaurs from what is now Europe.” ScienceDaily. ScienceDaily, 13 October 2016. <www.sciencedaily.com/releases/2016/10/161013095748.htm>.

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WFS News: Stegosaurus plates may have differed between male, female

October 13th, 2016

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Stegosaurus, a large, herbivorous dinosaur with two staggered rows of bony plates along its back and two pairs of spikes at the end of its tail, lived roughly 150 million years ago during the Late Jurassic in the western United States.

Some individuals had wide plates, some had tall, with the wide plates being up to 45 per cent larger overall than the tall plates. According to the new study, the tall-plated Stegosaurus and the wide-plate Stegosaurus were not two distinct species, nor were they individuals of different age: they were actually males and females.

Professor Michael Benton, Director of the Masters in Palaeobiology at the University of Bristol said: “Evan made this discovery while he was completing his undergraduate thesis at Princeton University. It’s very impressive when an undergraduate makes such a major scientific discovery.”

Some Stegosaurus had wide plates, some had tall, with the wide plates being up to 45 percent larger overall than the tall plates. According to a new study by University of Bristol, UK student, Evan Saitta, the tall-plated Stegosaurus and the wide-plated Stegosaurus were not two distinct species, nor were they individuals of different age: they were actually males and females. This is the first convincing evidence for sexual differences in a species of dinosaur.
Credit: Copyright Evan Saitta

Sexual dimorphism (a term used to describe distinct anatomical differences between males and females of the same species) is common in living animals — think of the manes of lions or the antlers of deer — yet is surprisingly difficult to determine in extinct species.

Despite many previous claims of sexual dimorphism in dinosaurs, current researchers find them to be inconclusive because they do not rule out other possible explanations for why differences in anatomy might be present between fossil specimens. For example, two individuals that differ in anatomy might be two separate species, a young and an old individual, or a male and a female individual.

Having spent six summers in central Montana as part of an excavation crew digging up the first ever Stegosaurus‘graveyard’, Evan Saitta was able to test these alternative explanations and others in the species Stegosaurus mjosi.

The group of dinosaurs excavated in Montana demonstrated the coexistence of individuals that only varied in their plates. Other skeletal differences indicating separation of ecological niches would have been expected if the two were different species.

The study also found that the two varieties were not a result of growth. CT scanning at Billings Clinic in Montana, as well as thin sections sampled from the plates for microscope analysis, showed that the bone tissues had ceased growing in both varieties. Neither type of plate was in the process of growing into the other.

With other possibilities ruled out, the best explanation for the two varieties of plates is that one type belonged to males and the other, females.

Speculating about which is which, Evan Saitta said: “As males typically invest more in their ornamentation, the larger, wide plates likely came from males. These broad plates would have provided a great display surface to attract mates. The tall plates might have functioned as prickly predator deterrents in females.”

Stegosaurus may not have been the only dinosaur to exhibit sexual dimorphism. Other species showed extra-large crests or nose horns, which were potentially sexual features. Male animals often fight or display for mates, just like red deer or peacocks today.

Not only does Saitta’s work show that dinosaurs exhibited sexual dimorphism, it suggests that the ornamentation of at least some species was used for sexual display.

The presence of sexual dimorphism in an extinct species can provide scientists with a much clearer picture of its behaviour than would otherwise be possible.

Source: Saitta ET (2015). Evidence for Sexual Dimorphism in the Plated Dinosaur Stegosaurus mjosi (Ornithischia, Stegosauria) from the Morrison Formation (Upper Jurassic) of Western USA. PLoS ONE, 2015 DOI:10.1371/journal.pone.0123503 & Science Daily.

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WFS News: The first sea turtle??

October 11th, 2016

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Several 80-million-year-old fossils found in Alabama are from a species of sea turtle that is the oldest known member of the lineage that gave rise to all modern species of sea turtle, according to new research from the University of Alabama at Birmingham.

Researchers from the College of Arts and Sciences’ Department of Biology worked with two relatively complete turtle skeletons, along with several smaller pieces, that are housed at Birmingham’s McWane Science Center, to unearth the evolutionary clues tying the ancient turtles to modern sea turtles, and confirm the existence of that ancient species, previously known only from a few isolated fragments.

The McWane fossils help solve a long-standing debate as to whether this animal was a unique species. They also provide insights into the evolutionary history of living species of sea turtles, including the Kemp’s Ridley, Loggerhead and the endangered Green sea turtle.

According to research published in the Journal of Systematic Palaeontology, the fossils belong to Ctenochelys (tee-no-key-lees) acris, a marine-adapted turtle that lived in the shallow, subtropical sea that once covered most of Alabama. By dating the rock formation from which these fossils were recovered, C. acris is presumed to have lived more than 80 million years ago, during the Late Cretaceous, a period of time when sea turtle diversity was at an all-time high.

“Climatic warming during the mid-Cretaceous resulted in elevated sea levels and temperatures that, in turn, provided an abundance of new niches for marine turtles to invade,” said Drew Gentry, a UAB biology doctoral student and the lead researcher on the project. “Represented today by only seven living species, sea turtles were once one of the most diverse lineages of marine reptiles. Before the cataclysm that claimed the dinosaurs, there may have been dozens of specialized species of sea turtle living in different oceanic habitats around the world.”

Before this research, so little fossil evidence for C. acris had been documented that most paleontologists doubted the species was real. Not only do the newly discovered fossils prove C. acrisexisted, they may also be a critical piece in a much larger puzzle of sea turtle evolution.

Silhouette of Ctenochelys acris overlaid with some of the fossils used to reconstruct the species.Credit: Drew Gentry, UAB

“There is strong evidence which indicates freshwater turtles may have evolved to occupy marine environments at several points in the past,” Gentry said. “But most of those lineages went extinct, making the exact origins of living or ‘true’ sea turtles somewhat of a mystery.”

Evidence gathered from the fossils of C. acris suggests the earliest ancestors of modern sea turtles may have come from the Deep South. By comparing the skeleton of C. acris with those of both extinct and living species of turtles, Gentry discovered thatC. acris possessed traits of both sea turtles and their closest living turtle relatives, snapping turtles.

“This animal was a bottom-dwelling sea turtle that fed primarily on mollusks and small invertebrates,” he said. “Unlike the ‘rudder-like’ hind-limbs of today’s sea turtles, C. acris had large, powerful hind-limbs to help push it through the water, a lot like a modern-day snapping turtle.

“Data from C. acris tell us not only that marine turtles are capable of occupying specialized oceanic niches, but also that many of the sea turtles we know today may have gotten their evolutionary start as something similar to an oversized snapping turtle in what eventually became the southeastern United States.”

Studying the diversity and evolutionary history of sea turtles during previous periods of climate change can provide meaningful insights into what effects climate and environmental changes might have on modern marine turtle populations.

“An important, yet often overlooked, aspect of sea turtle research is their evolutionary history,” Gentry said. “By analyzing the remains of fossil species, we can begin to understand the origins of these animals and how they’ve adapted to different environments over time.”

The fossils that led to this research were discovered in 1986 and contributed to what was then the Red Mountain Museum. The McWane Science Center was founded in 1998 by the merger of the Red Mountain Museum and a nearby children’s museum, Discovery Place.

The paleontological and archaeological collection at McWane is one of the largest in the southeastern U.S. and houses a number of significant finds from across Alabama, including the recently announced Eotrachodon, a type of duck-billed dinosaur.

“We are always making discoveries from the specimens housed at McWane that give us new respect for the individuals who contributed to this collection,” Gentry said.

Citation : University of Alabama at Birmingham. “Fossil from oldest ancestor of modern sea turtles.” ScienceDaily. ScienceDaily, 3 October 2016. <www.sciencedaily.com/releases/2016/10/161003182513.htm>.

KEY: WFS,World Fossil Society,Riffin T Sajeev, Russel T Sajeev

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