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

Fossil Kooteninchela deppi named after the actor Johnny Depp

May 19th, 2013

Riffin

A scientist has discovered an ancient extinct creature with ‘scissor hand-like’ claws in fossil records and has named it in honour of his favourite movie star.

The 505-million-year-old fossil called Kooteninchela deppi (pronounced Koo-ten-ee-che-la depp-eye), which is a distant ancestor of lobsters and scorpions, was named after the actor Johnny Depp for his starring role as Edward Scissorhands — a movie about an artificial man named Edward, an unfinished creation, who has scissors for hands.

Kooteninchela deppi is helping researchers to piece together more information about life on Earth during the Cambrian period when nearly all modern animal types emerged.

David Legg, who carried out the research as part of his PhD in the Department of Earth Science and Engineering at Imperial College London, says:

“When I first saw the pair of isolated claws in the fossil records of this species I could not help but think of Edward Scissorhands. Even the genus name, Kootenichela, includes the reference to this film as ‘chela’ is Latin for claws or scissors. In truth, I am also a bit of a Depp fan and so what better way to honour the man than to immortalise him as an ancient creature that once roamed the sea?”

Kootenichela reconstruction. (Credit: Image courtesy of Imperial College London)

Kooteninchela deppi lived in very shallow seas, similar to modern coastal environments, off the cost of British Columbia in Canada, which was situated much closer to the equator 500 million years ago. The sea temperature would have been much hotter than it is today and although coral reefs had not yet been established, Kooteninchela deppi would have lived in a similar environment consisting of sponges.

The researcher believes that Kooteninchela deppi would have been a hunter or scavenger. Its large Edward Scissorhands-like claws with their elongated spines may have been used to capture prey, or they could have helped it to probe the sea floor looking for sea creatures hiding in sediment.

Kooteninchela deppi was approximately four centimetres long with an elongated trunk for a body and millipede-like legs, which it used to scuttle along the sea floor with the occasional short swim.

It also had large eyes composed of many lenses like the compound eyes of a fly. They were positioned on top of movable stalks called peduncles to help it more easily search for food and look out for predators.

The researcher discovered that Kooteninchela deppi belongs to a group known as the ‘great-appendage’ arthropods, or megacheirans, which refers to the enlarged pincer-like frontal claws that they share. The ‘great-appendage’ arthropods are an early relation of arthropods, which includes spiders, scorpions, centipedes, millipedes, insects and crabs.

David Legg adds: “Just imagine it: the prawns covered in mayonnaise in your sandwich, the spider climbing up your wall and even the fly that has been banging into your window and annoyingly flying into your face are all descendants of Kooteninchela deppi. Current estimates indicate that there are more than one million known insects and potentially 10 million more yet to be categorised, which potentially means that Kooteninchela Deppi has a huge family tree.”

In the future, David Legg intends to further his research and study fossilised creatures from the Ordovician, the geological period that saw the largest increase in diversity of species on the planet. He hopes to understand why this happened in order to learn more about the current diversity of species on Earth.

The research was published in the Journal of Palaeontology 2 May 2013.

The Eloquence of Otoliths Seen in a 23-Million-Year-Old Fish Fossil

May 18th, 2013

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Fish fossils that are about 23 million years old give unprecedented insight into the evolutionary history of the gobioid order, one of the most species-rich groups among the modern bony fishes.

Researchers led by paleontologist Professor Bettina Reichenbacher from the Division of Paleontology and Geobiology at the Department of Earth and Environmental Sciences at Ludwig-Maximilians-Universitaet (LMU) in Munich / Germany have completed a comprehensive analysis of fish fossils which they assign to the group of bony fishes that includes the gobies. Their results, which have just appeared in the journal PLOS ONE, provide new insights into the evolutionary history of these fish and also have implications for their taxonomy.

Osteology, scales and otolith of †Lepidocottus aries (Agassiz). (Credit: Christoph Gierl et al. An Extraordinary Gobioid Fish Fossil from Southern France. PLoS ONE, 2013; 8 (5): e64117 DOI: 10.1371/journal.pone.0064117)

The fossil material examined is unusually well preserved. “This has allowed us to describe a gobioid fossil in greater detail than ever before,” says Reichenbacher. Indeed, the authors of the new study have been able to show that the fossil species concerned does not belong to the true gobies at all, in contrast to what earlier investigators had concluded. It is a member of an enigmatic family now known as the Butidae. Until very recently Butidae had been classified among the sleeper gobies. The family is now recognized as a separate clade, whose members are found in tropical river systems of Africa, Madagascar, Asia and Australia. Furthermore, no fossil specimens that could be attributed to this family have been identified until now. Indeed, datable gobioid fossils are comparatively rare in the fossil record. Since fossils of known age provide chronological markers of phylogeny, this has hampered understanding of the evolutionary history of this highly successful group of fishes.

The signature ear-stones

The new description published by the LMU team, in collaboration with a group of French researchers, is based on material that was discovered in the South of France and made available for study by the Cuvier Museum in Montbéliard. The specimens were excavated from sediments that had been laid down in a shallow lagoon near the coast of the Tethys Sea, the precursor of the modern Mediterranean, towards the end of the Oligocene epoch, around 23 million years ago. Among the many unusual features of the find is the fact that the otoliths (also known as ear-stones), which are small calcified particles that form part of the balance organs in the inner ear of bony fish, are perfectly preserved. Reichenbacher, who specializes in the analysis of fossil otoliths, explains the significance of this: “Otoliths are made up of the mineral aragonite, together with a minor fraction of organic material. What makes them of such interest for us is that they can be read like a genetic code. Otoliths allow us to deduce what sort of fish they belonged to, even if nothing else has survived,” she says. This is why the ear-stones play such a crucial role in studies of the paleontology, evolutionary history and biodiversity of the teleosts.

The otoliths revealed to the researchers that the fossils did not actually belong among the true gobies, but should be assigned to either the sleeper gobies or the butids. “Among the skeletal elements of the fossils, we then identified other traits that confirmed this assessment and enabled us to place the species among the butids,” says doctoral student Christoph Gierl, who analyzed the structural anatomy of the skull and the dorsal and pelvic fins.

This is the first butid fossil to be found anywhere. Interestingly, no members of the Butidae are found in European waters today. The new findings show that, back in the Oligocene, butids were distributed in estuaries and lagoons around the Tethys and the Paratethys (the remnant sea to the northeast that was cut off from the rest of the Tethys Sea, today’s Mediterranean, when the Alps were formed), which were then located in subtropical latitudes. The family vanished from these waters during the Early Miocene, about 22 million years ago. “They were probably displaced by true gobies that were more adaptable,” says Reichenbacher.

The researchers expect that their study will lead to a better picture of the evolutionary history of the gobioids as a whole. “Our results also demonstrate that otoliths can play a much greater role in the classification of gobioids than has previously been appreciated,” Bettina Reichenbacher concludes.

Clam Fossils Divulge Secrets of Ecologic Stability

May 17th, 2013

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Clam fossils from the middle Devonian era — some 380 million years ago — now yield a better paleontological picture of the capacity of ecosystems to remain stable in the face of environmental change, according to research published today (May 15) in the online journal PLOS ONE.

Trained to examine species abundance — the head counts of specimens — paleontologists test the stability of Earth’s past ecosystems. The research shows that factors such as predation and organism body size from epochs-gone-by can now be considered in such detective work.

Clam fossils from the Devonian Sea, which are now found in the Finger Lakes region of New York, bear the scars from attackers some 380 million years ago. (Credit: Image courtesy of Cornell University)

Back 380 million years ago, New York was under the Devonian sea. Today, the fossils found in the rocks of this region have become well known for documenting long-term stability in species composition — that is, the same species have been found to persist with little change over a 5 million year period. But research has found that species abundance in this ancient ecosystem went up and down, generating debate among paleontologists whether the fauna, as a whole, was also stable in terms of its ecology.

A team of Cornell, Paleontological Research Institution (PRI) — an affiliate of Cornell — and University of Cincinnati researchers revisited this debate by examining the ecological stability of the Devonian clam fauna.

“To understand how these species fared in the Devonian, you have to look at how they interacted with other species. There is more to ecology than just the abundance and distribution of species,” said Gregory Dietl, Cornell adjunct professor, earth and atmospheric sciences, and a paleontologist at PRI.

The research, “Abundance Is Not Enough: The Need for Multiple Lines of Evidence in Testing for Ecological Stability in the Fossil Record,” was written by Judith Nagel-Myers, paleontologist, PRI; John Handley, PRI; Carlton Brett, University of Cincinnati professor of geology; and Dietl.

The scientists took a new approach to testing ecological stability: In addition to counting numbers of clams, they examined repair scars on fossil clams that were left by the unsuccessful attacks from shell-crushing predators, and the body size of the clam assemblage as it yields biological information on the structure of food webs.

“Surprisingly, predation pressure and the body size structure of the clams remained stable, even as abundance varied,” said Nagel-Myers. Possible mechanisms that explain the clam assemblage’s stability are related to the dynamics of food webs — the same mechanisms operating in food webs today. In one mechanism, predators switched between feeding on different clam species as their abundance varied.

The ancient Devonian ecosystem was more complex than previously thought, as it cautions scientists against basing conclusions on a single factor. Said Dietl: “Our results thus raise serious doubt as to whether ecological stability can be tested meaningfully, solely based upon the abundance of taxa, which has been the standard metric used to test for ecological stability in paleoecology.”

Dynamics of plate tectonics : A modern approach

May 16th, 2013

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SYDNEY: A new theory explains why tectonic plates move at different rates and solves other long-standing problems in Earth sciences, Australian scientists said.

A diagram of a subduction zone, where one plate is pushed under the other, dragging the rest of the plate behind it. Credit: NASA

The rate at which tectonic plates move depends on the width of its associated subduction zone – a place where two tectonic plates meet, and the thicker plate is pushed under the other.

The theory explains why the Australian Plate moves much faster than other plates, and explains the disintegration of a mountain range in North America, among other puzzles.

Subduction zones affect plate velocity

Previous theories and hypothesises, such as the idea that plate velocity depended on the age of the plate, have been unable to explain simultaneously the velocity of the different plates and the velocity of subduction zones.

But when geoscientist Wouter Schellart from Monash University in Melbourne, Australia, and his team compiled measurements of all the tectonic plates – 15 large tectonic plates and 30 smaller ones – and all the subduction zones on Earth, they noticed a clear pattern:

“The width of the subducted plate that has gone down into the mantle at the subduction zone determines the velocity of both the plate and the subduction zone plate boundary,” said Shellart, whose finding were reported in the journal Science.

Ancient mysteries of tectonic plates

The researchers also ran an advanced four-dimensional computer simulation of the Earth’s plates and their subduction zone boundaries. “We found the same velocities and patterns as observed in the data, thereby confirming our hypothesis.”

This research helps solve some ancient mysteries involving plate tectonics. The ancient Farallon Plate, once called the Juan de Fuca Plate and located where Utah in the U.S. sits today, slowed down from 10 cm per year 50 million years ago to just two centimetres per year today.

Schellart and his team showed that during this period the subduction zone reduced in size from 14,000km to only 1,400km, which was the cause for the slowing of the plate, and the crumbling of an associated mountain range.

Mountains rise … and crumble

When the Farallon Plate was moving faster, North America had an extensive mountain chain running similar to that of the Andes today.

But “as the width of the plate decreased, the slab could no longer support the massive mountain range, and it started to retreat westward by itself, thereby destroying the mountain range and extending the North American continent, forming the Basin and Range Province,” Schellart said.

The research also explains why some plates move much faster than others.

Fast-moving Australian Plate

“The Australian Plate moves rapidly northward at some six centimetres per year, which can be prescribed to the wide subduction zones at its boundary, namely the Sunda [Indonesian] subduction zone and the Melanesia subduction zone, where the plate subducts beneath New Britain, Solomon and Vanuatu islands” Schellart said.

Not every plate moves this quickly – the African plate moves northward at just one or two centimetres per year. “This can be ascribed to the narrow subduction zones that are located at its northern boundary, namely the Calabrian subduction zone, where the plate subducts below southern Italy, and the Hellenic subduction zone, where the plate subducts below the Greek islands,” Schellart said.

Craig O’Neil, a geoscientist at Macquarie University in Sydney describes the research work as critically important, in particular the fact that Schallart is changing the idea of Earth science from a 2-D modelling to a 3-D dynamic system.

“Thinking of the Earth in 3-D is critical if we want to understand the geological record, and why the surface plates are moving the way they do.”

Source: Article by Emma Bastian

Hearing the Russian Meteor, in America: Sound Arrived in 10 Hours, Lasted 10 More

May 15th, 2013

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How powerful was February’s meteor that crashed into Russia? Strong enough that its explosive entry into our atmosphere was detected almost 6,000 miles away in Lilburn, Ga., by infrasound sensors — a full 10 hours after the meteor’s explosion. A Georgia Tech researcher has modified the signals and made them audible, allowing audiences to “hear” what the meteor’s waves sounded like as they moved around the globe on February 15.

Infrasound signals associated with the Russian meteor impact on February 15, 2013, recorded nearly 9,600 km away in Lilburn, Georgia. The sound took about 10 hours to travel from Russia to Georgia. (Credit: The seismic data is distributed by the IRIS DMC, TA/USArray network/Image from video courtesy of Georgia Institute of Technology)

Lilburn is home to one of nearly 400 USArray seismic/infrasound stations in use in the eastern United States. They are part of a large-scale project named “Earthscope,” an initiative funded by the National Science Foundation that studies Earth’s interior beneath North America. The stations are mainly deployed to record seismic waves generated from earthquakes, but their sound sensors can record ultra long-period sound waves, also known as infrasound waves.

The human ear cannot hear these infrasound signals. However, by playing the data faster than true speed, Georgia Tech faculty member Zhigang Peng increased the sound waves’ frequency to audible levels. The Incorporated Research Institutions for Seismology’s Data Managment Center provided the data.

“The sound started at about 10 hours after the explosion and lasted for another 10 hours in Georgia,” said Peng, an associate professor in the School of Earth and Atmospheric Sciences. He’s confident that the sound is associated with the meteor impact because a slow propagation of the sound waves can be seen across the entire collection of US Array stations, as well as other stations in Alaska and polar regions.

“They are like tsunami waves induced by large earthquakes,” Peng added. “Their traveling speeds are similar, but the infrasound propagates in the atmosphere rather than in deep oceans.”

Scientists believe the meteor was about 55 feet in diameter, weighed more than 7,000 tons and raced through the sky at 40,000 miles an hour. Its energy was estimated at 30 nuclear bombs. More than 1,500 people were hurt.

Using the same sonification process, Peng also converted seismic waves from North Korea’s nuclear test on February 12 and an earthquake in Nevada the next day. Each registered as a 5.1 magnitude event but created different sounds. The measurements were collected by seismic instruments located about 100 to 200 miles from each event. For further comparison, Peng has also created a seismic recording of the meteor impact at a similar distance.

“The initial sound of the nuclear explosion is much stronger, likely due to the efficient generation of compressional wave (P wave) for an explosive source,” said Peng. “In comparison, the earthquake generated stronger shear waves that arrived later than its P wave.”

Peng says the seismic signal from the meteor is relatively small, even after being amplified by 10 times. According to Peng, this is mainly because most of the energy from the meteor explosion propagated as the infrasound displayed in the initial sound clip. Only a very small portion was turned into seimsic waves propagating inside Earth.

This isn’t the first time Peng has converted seismic data into audible files. He also sonified 2011’s historic Tohoku-Oki, Japan, earthquake as it moved through Earth and around the globe.

The seismic and sound data generated by the meteor impact and other sources can be used to demonstrate their global impact. Scientists are also using them to better understand their source characterizations and how they propagate above and inside Earth.

Video: https://www.youtube.com/watch?v=i1ey5zc6TOo

Impact of Sauropod Dinosaurs on Lagoonal Substrates in the Broome Sandstone (Lower Cretaceous), Western Australia

May 14th, 2013

Riffin

Existing knowledge of the tracks left by sauropod dinosaurs (loosely ‘brontosaurs’) is essentially two-dimensional, derived mainly from footprints exposed on bedding planes, but examples in the Broome Sandstone (Early Cretaceous) of Western Australia provide a complementary three-dimensional picture showing the extent to which walking sauropods could deform the ground beneath their feet. The patterns of deformation created by sauropods traversing thinly-stratified lagoonal deposits of the Broome Sandstone are unprecedented in their extent and structural complexity. The stacks of transmitted reliefs (underprints or ghost prints) beneath individual footfalls are nested into a hierarchy of deeper and more inclusive basins and troughs which eventually attain the size of minor tectonic features. Ultimately the sauropod track-makers deformed the substrate to such an extent that they remodelled the topography of the landscape they inhabited. Such patterns of substrate deformation are revealed by investigating fragmentary and eroded footprints, not by the conventional search for pristine footprints on intact bedding planes. For that reason it is not known whether similar patterns of substrate deformation might occur at sauropod track-sites elsewhere in the world.

Cretaceous sauropod tracks and their potential rack-makers.
A, silhouette of Diamantinasaurus, a titanosaur or related sauropod from the Winton Formation (Albian-Cenomanian) of Queensland (after Hocknull et al. [40]); scale bar indicates 1 metre. B, silhouette of Brachiosaurus (after Farlow [19]); undescribed skeletal fragments of a similar sauropod are also known to occur in the Rolling Downs Group of Queensland; scale bar indicates 1 metre. C, right manus-pes couple (at right) and D, part of a trackway (at left), of Brontopodus birdi, a distinctive form of sauropod track from the Trinity Group (Early Cretaceous, Comanchean) of Texas and Arkansas; after Farlow et al. [38]); long suspected to be the track of the contemporary brachiosaur Pleurocoelus, but more recently attributed [58] to Paluxysaurus, a relative of Brachiosaurus; length of the pes print ranges from 40–50 cm to more than 100 cm. E, a sample of sauropod tracks from the Broome Sandstone, Western Australia, to illustrate their diversity in size and shape; three isolated pes prints (at left) and three manus-pes couple (at right) are shown at uniform scale; scale bar (extreme left) is 1 metre.
doi:10.1371/journal.pone.0036208.g002

Variation in colour of Broome Sandstone and its sauropod dinosaur tracks.
A, freshly-exposed and conspicuous example of a pes (hindfoot) print; the thinly layered sediments are characteristic of lagoonal substrates in the Broome Sandstone, though the vivid coloration is often subdued by weathering; scale is 1 ft (c. 31 cm) wooden ruler. B, pes print impressed in, and filled by, blue-grey siltstone; examples such as this are difficult to detect when sea-water has evaporated from the erosion pits along the interface between cast and mould; scale indicated by camera lens cap (diameter 6.7 cm) at lower left.
doi:10.1371/journal.pone.0036208.g003

Series of diagrams explaining origin of the specimen shown in Figure 8B.
A, sauropod footprint impressed into substrate; the footprint, a natural mould (concave epirelief) is bordered by a raised rim of displaced sediment. B, the footprint mould lies at the centre of a larger depression, apparently a zone of subsidence or down-warping created by the impact of the track-maker’s foot. C, the area is buried by an influx of sediment which fills the footprint mould to form the natural cast. D, much later, after lithification, the two layers of rock are separated by natural breakage and erosion. E, the upper layer is overturned by waves to expose its convex lower surface with the footprint cast surrounded by a gutter. Smaller features in Figure 8B (manus print and ripple-marks) are omitted for the sake of clarity.
doi:10.1371/journal.pone.0036208.g009

Citation: Thulborn T (2012) Impact of Sauropod Dinosaurs on Lagoonal Substrates in the Broome Sandstone (Lower Cretaceous), Western Australia. PLoS ONE 7(5): e36208. doi:10.1371/journal.pone.0036208

Editor: Andrew A. Farke, Raymond M. Alf Museum of Paleontology, United States of America

WFS Profiles : William Buckland

May 13th, 2013

Riffin

Buckland was born at Axminster in Devon and, as a child, would accompany his father, the Rector of Templeton and Trusham, on his walks where interest in road improvements led to collecting fossil shells, including ammonites, from the Jurassic lias rocks exposed in local quarries.

He was educated first at Blundell’s School, Tiverton, Devon, and then at Winchester College, from where in 1801 he won a scholarship to study for the ministry at Corpus Christi College, Oxford, also attending the lectures of John Kidd on mineralogy and chemistry, as well as developing an interest in geology and carrying out field research on strata, during vacations. Having taken his BA in 1804, he went on to obtain his MA degree in 1808. He then became a Fellow of Corpus Christi in 1809, was ordained as a priest and continued to make frequent geological excursions, on horseback, to various parts of England, Scotland, Ireland and Wales. In 1813, he was appointed reader in mineralogy, in succession to John Kidd, giving lively and popular lectures with increasing emphasis on geology and palaeontology. As (unofficial) curator of the Ashmolean Museum, he built up collections, touring Europe and coming into contact with scientists including Georges Cuvier.

In 1818, Buckland was elected a fellow of the Royal Society. That year he persuaded the Prince Regent to endow an additional Readership, this time in Geology and he became the first holder of the new appointment, delivering his inaugural address on 15 May 1819. This was published in 1820 as Vindiciæ Geologiæ; or the Connexion of Geology with Religion explained, both justifying the new science of geology and reconciling geological evidence with the biblical accounts of creation and Noah’s Flood. At a time when others were coming under the opposing influence of James Hutton‘s theory of uniformitarianism, Buckland developed a new hypothesis that the word “beginning” in Genesis meant an undefined period between the origin of the earth and the creation of its current inhabitants, during which a long series of extinctions and successive creations of new kinds of plants and animals had occurred. Thus, his catastrophism theory incorporated a version of Old Earth creationism or Gap creationism. Buckland believed in a global deluge during the time of Noah but was not a supporter of flood geology as he believed that only a small amount of the strata could have been formed in the single year occupied by the deluge.

From his investigations of fossil bones at Kirkdale Cave, in Yorkshire, he concluded that the cave had actually been inhabited by hyaenas in antediluvian times, and that the fossils were the remains of these hyaenas and the animals they had eaten, rather than being remains of animals that had perished in the Flood and then carried from the tropics by the surging waters, as he and others had at first thought.

Around the end of 1849, he contracted a disease which increasingly disabled him until his death in 1856. Post-mortem examination identified a tubercular infection of the upper cervical vertebrae which had spread to the brain. The plot for his grave had been reserved but, when the gravedigger set to work, it was found that an outcrop of solid Jurassic limestone lay just below ground level and explosives had to be used for excavation. This may have been a last jest by the noted geologist, reminiscent of Richard Whatley’s Elegy intended for Professor Buckland written in 1820:

Where shall we our great Professor inter

That in peace may rest his bones?

If we hew him a rocky sepulchre

He’ll rise and break the stones

And examine each stratum that lies around

For he’s quite in his element underground

Source : Wikipedia

Disparity Changes in 370 Ma Devonian Fossils: The Signature of Ecological Dynamics?

May 12th, 2013

Riffin

Early periods in Earth’s history have seen a progressive increase in complexity of the ecosystems, but also dramatic crises decimating the biosphere. Such patterns are usually considered as large-scale changes among supra-specific groups, including morphological novelties, radiation, and extinctions. Nevertheless, in the same time, each species evolved by the way of micro-evolutionary processes, extended over millions of years into the evolution of lineages. How these two evolutionary scales interacted is a challenging issue because this requires bridging a gap between scales of observation and processes. The present study aims at transferring a typical macro-evolutionary approach, namely disparity analysis, to the study of fine-scale evolutionary variations in order to decipher what processes actually drove the dynamics of diversity at a micro-evolutionary level. The Late Frasnian to Late Famennian period was selected because it is punctuated by two major macro-evolutionary crises, as well as a progressive diversification of marine ecosystem. Disparity was estimated through this period on conodonts, tooth-like fossil remains of small eel-like predators that were part of the nektonic fauna. The study was focused on the emblematic genus of the period, Palmatolepis. Strikingly, both crises affected an already impoverished Palmatolepis disparity, increasing risks of random extinction. The major disparity signal rather emerged as a cycle of increase and decrease in disparity during the inter-crises period. The diversification shortly followed the first crisis and might correspond to an opportunistic occupation of empty ecological niche. The subsequent oriented shrinking in the morphospace occupation suggests that the ecological space available to Palmatolepis decreased through time, due to a combination of factors: deteriorating climate, expansion of competitors and predators. Disparity changes of Palmatolepis thus reflect changes in the structure of the ecological space itself, which was prone to evolve during this ancient period where modern ecosystems were progressively shaped.

Temporal and geographical sampling, and terminology on conodont elements.
(A) Timescale, composite section along the end Frasnian and the Famennian and stratigraphic log of the studied sections. Absolute ages after [24] and conodont zones after [77]. Note that the postera and expansa zones are not sampled. Along the stratigraphic log of each section, dots represent the sampled levels. Abbreviations: E = Early, M = Middle, L = Late. (B) Paleogeographic map [19] of the Famennian. Circles = location of the French (blue circle) and German (red circle) sections contributing to the composite section. Black dots = location of the sections that delivered additional sampling of Palmatolepis (Palmatolepis) linguiformis. (C) Illustration of Palmatolepis platform elements, with the terminology of the morphological features used in taxonomy. To the left a specimen of Pa. (Palmatolepis) rugosa (trachytera zone). To the right a specimen of Pa. (Manticolepis) rotunda (rhenana zone).
doi:10.1371/journal.pone.0036230.g001

Citation: Girard C, Renaud S (2012) Disparity Changes in 370 Ma Devonian Fossils: The Signature of Ecological Dynamics? PLoS ONE 7(4): e36230. doi:10.1371/journal.pone.0036230

Editor: Brock Fenton, University of Western Ontario, Canada

Dusting for Prints from a Fossil Fish to Understand Evolutionary Change

May 11th, 2013

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In 370 million-year-old red sandstone deposits in a highway roadcut, scientists have discovered a new species of armored fish in north central Pennsylvania.

Fossils of armored fishes like this one, a phyllolepid placoderm, are known for the distinctive ornamentation of ridges on their exterior plates. As with many such fossils, scientists often find the remains of these species as impressions in stone, not as three-dimensional versions of their skeletons. Therefore, in the process of studying and describing this fish’s anatomy, scientists took advantage of a technique that may look a lot like it was stolen from crime scene investigators.

Illustration of the Devonian armored fish Phyllolepis thomsoni as it may have looked when alive. (Credit: Jason Poole, Academy of Natural Sciences of Drexel University)

Dr. Ted Daeschler has shown the fossil and made a rubber cast by pouring latex into its natural impression in the rock. Once the latex hardened, Daeschler peeled it out and dusted its surface with a fine powder to better show the edges of the bony plates and the shapes of fine ridges on the fish’s bony armor — a lot like dusting for fingerprints to show minute ridges left on a surface. With this clearer view, Daeschler and colleagues were better able to prepare a detailed scientific description of the new species.

This placoderm, named Phyllolepis thomsoni, is one of two new Devonian fish species described by Daeschler in the Bicentennial issue of the Proceedings of the Academy of Natural Sciences of Philadelphia, with different co-authors. The other new species is a lobe-finned fish discovered in northern Canada.

Both the Pennsylvania placoderm and the Canadian lobe-finned fish species are from the late Devonian period, at a time long before dinosaurs walked the Earth — but, geologically speaking, not long before the very first species began to walk on land. Daeschler studies Devonian species in particular to help describe the evolutionary setting that gave rise to the first vertebrate species with limbs. He has dug for Devonian species in Pennsylvania since 1993, and in northern Canada since 1999.

Daeschler, a vice president and associate curator at the Academy of Natural Sciences of Drexel University, and an associate professor in Drexel’s College of Arts and Sciences, and co-author Dr. John A. Long, a leading authority on placoderms from Flinders University in Australia, named the species in honor of Dr. Keith S. Thomson.

Four New Dinosaur Species Identified

May 10th, 2013

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Just when dinosaur researchers thought they had a thorough knowledge of ankylosaurs, a family of squat, armour plated, plant eaters, along comes University of Alberta graduate student, Victoria Arbour.

Arbour visited dinosaur fossil collections from Alberta to the U.K. examining skull armour and comparing those head details with other features of the fossilized ankylosaur remains. She made a breakthrough that resurrected research done more than 70 years ago.

CMN 0210 is the holotype of Euoplocephalus tutus, CMN 8530 is the holotype of Anodontosaurus lambei, MOR 433 is the holotype of Oohkotokia horneri, and ROM 784 is the holotype of Dyoplosaurus acutosquameus. AMNH 5337, AMNH 5405, CMN 0210, ROM 784, ROM 1930, TMP 1979.14.74, TMP 1991.127.1, TMP 1997.132.1, and UALVP 31 are from the Dinosaur Park Formation. AMNH 5238 and UALVP 47977 are of uncertain stratigraphic position within Dinosaur Provincial Park. AMNH 5223, CMN 8530, ROM 832, and TMP 1997.59.1 are from the Horseshoe Canyon Formation. NHMUK R4947 is from an unknown stratigraphic position in Alberta. MOR 433, TMP 2001.42.9 (much of the anterior rostrum in heavily reconstructed), and USNM 11892 are from the Upper Two Medicine Formation in Montana. Scale equals 10cm. (Credit: Victoria M. Arbour, Philip J. Currie; Photograph of ROM 832 by C. Brown, and of ROM 1930 by J. Arbour)

Arbour explains that between 1900 and 1930 researchers had determined that small variations in the skull armour and the tail clubs in some ankylosaurs constituted four individual species of the dinosaurs.

“In the 1970s the earlier work was discarded and those four species were lumped into one called species Euoplocephalus,” said Arbour.

“I examined many fossils and found I could group some fossils together because their skull armour corresponded with a particular shape of their tail club,” said Arbour.

Cranial anatomy of ankylosaurids, including terminology for ornamentation patterns.
ZPAL MgD II/1, juvenile Pinacosaurus grangeri in A) dorsal and B) left lateral views, showing boundaries of cranial bones. Boundaries between cranial bones are not visible in most adult ankylosaurids. C) UALVP 31, Euoplocephalus tutus, in dorsal view. D) CMN 8530, Anodontosaurus lambei (holotype), in left lateral view. Cranial ornamentation that is subdivided into discrete polygons (rather than generalized rugosity) are referred to as caputegulae. Abbreviations: asca, anterior supraorbital caputegulum; aso, anterior supraorbital; br, break or plaster; fr, frontal; frca, frontal caputegulum; j, jugal; lac, lacrimal; laca, lacrimal caputegulum; loca, loreal caputegulum; mnca, median nasal caputegulum; msca, middle supraorbital caputegulum; mso, middle supraorbital; mx, maxilla; nar, naris; nas, nasal; nasca, nasal caputegulum; nuca, nuchal caputegulum; orb, orbit; par, parietal; pmx, premaxilla; pnca, postnarial caputegulum; poca, postocular caputegulum; porb, postorbital; prf, prefrontal; prfca, prefrontal caputegulum; psca, posterior supraorbital caputegulum; pso, posterior supraorbital; pt, pterygoid; q, quadrate; qj, quadratojugal; qjh, quadratojugal horn; snca, supranarial caputegulum; sno, supranarial ornamentation; sq, squamosal; sqh, squamosal horn.
doi:10.1371/journal.pone.0062421.g002

Finding common features in fossils that come from the same geologic time is evidence that the original researchers were right says Arbour. “There were in fact four different species represented by what scientists previously thought was only one species, Euoplocephalus.”The four species span a period of about 10 million years. Arbour’s research shows three of those ankylosaurs species lived at the same time in what is now Dinosaur Provincial Park in southern Alberta.

Arbour says this opens the door to new questions.

“How did these three species shared their habitat, how did they divide food resources and manage to survive?” said Arbour.

Arbour will also look into how slight differences in skull ornamentation and tail shape between the species influenced the animals’ long reign on Earth.Arbour’s research was published May 8, in the journal PLOS ONE.

Abstract:

Few ankylosaurs are known from more than a single specimen, but the ankylosaurid Euoplocephalus tutus (from the Late Cretaceous of Alberta, Canada and Montana, USA) is represented by dozens of skulls and partial skeletons, and is therefore an important taxon for understanding intraspecific variation in ankylosaurs. Euoplocephalus is unusual compared to other dinosaurs from the Late Cretaceous of Alberta because it is recognized from the Dinosaur Park, Horseshoe Canyon, and Two Medicine formations. A comprehensive review of material attributed to Euoplocephalus finds support for the resurrection of its purported synonyms Anodontosaurus lambei and Scolosaurus cutleri, and the previously resurrected Dyoplosaurus acutosquameus. Anodontosaurus is found primarily in the Horseshoe Canyon Formation of Alberta and is characterized by ornamentation posterior to the orbits and on the first cervical half ring, and wide, triangular knob osteoderms. Euoplocephalus is primarily found in Megaherbivore Assemblage Zone 1 in the Dinosaur Park Formation of Alberta and is characterized by the absence of ornamentation posterior to the orbits and on the first cervical half ring, and keeled medial osteoderms on the first cervical half ring. Scolosaurus is found primarily in the Two Medicine Formation of Montana (although the holotype is from Dinosaur Provincial Park), and is characterized by long, back-swept squamosal horns, ornamentation posterior to the orbit, and low medial osteoderms on the first cervical half ring; Oohkotokia horneri is morphologically indistinguishable from Scolosaurus cutleri. Dyoplosaurus was previously differentiated from Euoplocephalus sensu lato by the morphology of the pelvis and pes, and these features also differentiate Dyoplosaurus from Anodontosaurus and Scolosaurus; a narrow tail club knob is probably also characteristic for Dyoplosaurus.

Citation: Arbour VM, Currie PJ (2013) Euoplocephalus tutus and the Diversity of Ankylosaurid Dinosaurs in the Late Cretaceous of Alberta, Canada, and Montana, USA. PLoS ONE 8(5): e62421. doi:10.1371/journal.pone.0062421

Editor: Andrew A. Farke, Raymond M. Alf Museum of Paleontology, United States of America