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

WFS Profiles:Dr. Robert T. Bakker

March 9th, 2013

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Dr. Robert T. Bakker is one of palaeontology greatest and most well known characters. Bakker was the first man who hypothesized that dinosaurs may have been warm-blooded, and was the scientist who believed that diseases caused the demise of the terrible lizards. He is also the author of the famous book The Dinosaur Heresies.

Bakker took his childhood love of dinosaurs to Yale University, where he studied under the great John Ostrom. Bakker later received his Ph.D. from Harvard University. He has taught at the University of Colorado and has held numerous jobs at several museums in Colorado and Wyoming, including the Tate Museum, where he is now the Adjunct Curator. Since the summer of 1974 he has returned to the famous Como Bluff dinosaur sites summer after summer in order to attempt to put dinosaurs in context.

Robert Bakker in 2008

Bakker’s Colorado field work has produced numerous results. Among his findings, he has located dinosaurs that lived in totally aquatic environments, and others that could have only lived in trees. He can also tell you that Stegosaurus was only common on well drained, dry soil. Apatosaurus and Camarasaurus were found everywhere, Bakker stated. Bakker has also done a great deal of field work in other states, including Montana, Utah, Oklahoma, other countries, including Mongolia, Zimbabwe, and Canada, and in numerous other quarries. He has also discovered the only complete Apatosaurus skull and the very first and earliest raptor found in the Camarasaurus quarry.

While Bakker’s field record is very impressive, he is internationally known for his controversial theories that continue to light up palaeontology, and science in general. The hypothesis that is always mentioned in the same breath as Bakker is his theory of warm blooded dinosaurs.

The hypothesis that Bakker has drawn the most heat for has been his notion that the dinosaurs were killed off not by an asteroid or volcano, but by disease. According to Bakker, a comet or asteroid would have killed everything. Instead, the answer lies in migration. When big animals are spreading and mixing, he says, extinctions occur. He points to the findings that Indian and African elephants make each other sick to strengthen his belief. “When a new animal or plant is introduced to a new habitat bad things happen,” he stated.

The palaeontology career of Dr. Robert T. Bakker has been full of exciting finds and controversial theories. While he may draw fire for some of his ideas, it is safe to say that Bakker’s theories have led to the new image of dinosaurs-smart, active, caring, and highly interesting beasts! Bob Bakker is also an ecumenical preacher. Such a combination makes him an excellent speaker that’s bound to draw big crowds to any public event.

Reanalysis of “Raptorex kriegsteini”: A Juvenile Tyrannosaurid Dinosaur from Mongolia

March 9th, 2013

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The carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and massive robust skulls with laterally thickened teeth. The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the distinctive anatomical traits of derived tyrannosaurids were acquired in the Early Cretaceous, before the evolution of large body size. This inference depends on two core interpretations: that the holotype (LH PV18) derives from the Lower Cretaceous of China, and that despite its small size, it is a subadult or young adult. Here we show that the published data is equivocal regarding stratigraphic position and that ontogenetic reanalysis shows there is no reason to conclude that LH PV18 has reached this level of maturity. The probable juvenile status of LH PV18 makes its use as a holotype unreliable, since diagnostic features of Raptorex may be symptomatic of its immature status, rather than its actual phylogenetic position. These findings are consistent with the original sale description of LH PV18 as a juvenile Tarbosaurus from the Upper Cretaceous of Mongolia. Consequently, we suggest that there is currently no evidence to support the conclusion that tyrannosaurid skeletal design first evolved in the Early Cretaceous at small body size.

Comparison of the LH PV18 fish centrum (D) to an ellimmichthyiform centrum (A–C) (Horseshoeichthyes) from the Dinosaur Park Formation (Campanian) of Alberta.

The researchers concluded as LH PV18 cannot be demonstrated to be from the Lower Cretaceous, therefore the conclusion that derived features of tyrannosaurids evolved before the Late Cretaceous cannot be supported. As histology demonstrates that LH PV18 is immature then the conclusion that typical tyrannosaurid features evolved at a small size also cannot be supported, since the small size of LH PV18 is more likely the result of its immature status. Furthermore, the probable juvenile status of LH PV18 makes its use as a holotype unreliable, since diagnostic features of Raptorex may be symptomatic of its immature status, rather than its actual phylogenetic position. Unless stronger evidence is presented, Raptorex should be considered a nomen dubium. LH PV18 more likely represents the juvenile of a larger tyrannosaurid from the Late Cretaceous of Mongolia, such as Tarbosaurus (as per its original sale description), although testing of this hypothesis awaits description of new specimens of immature tyrannosaurids.

Misidentification of immature dinosaur specimens as new taxa is a persistent and increasingly pervasive problem that can be detected and diagnosed only by thorough and proper histological analysis. Combined ontogenetic and stratigraphic analyses have great potential to reveal new information on the mode and tempo of dinosaur evolution, but as this reanalysis exemplifies, such studies must be based upon solid and replicable data.

Citation: Fowler DW, Woodward HN, Freedman EA, Larson PL, Horner JR (2011) Reanalysis of “Raptorex kriegsteini”: A Juvenile Tyrannosaurid Dinosaur from Mongolia. PLoS ONE 6(6): e21376. doi:10.1371/journal.pone.0021376

Editor: Anjali Goswami, University College London, United Kingdom

Research shows Snakes originated on land

March 8th, 2013

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One of the most primitive snake fossils have debunked the belief that the slithery reptiles had originated in the sea, suggesting instead that they were the creatures of land.

The animal, which lived at the same time as the dinosaurs, probably emerged from a line of burrowing reptiles that eventually lost their legs.

Where and how snakes diverged from their legged cousins the lizards is still a mystery.

The debate over snake origins has been hampered by the scarcity of transitional fossils.

But new fossils from eastern Wyoming, US, belonging to the ancient snake Coniophis precedens – which lived some 65-70 million years ago – could help clear up the mystery.

According to the analysis by Nicholas Longrich from Yale University and his colleagues, Coniophis lived in a floodplain environment and “lacks adaptations for aquatic locomotion”.

They describe it as a “transitional snake, combining a snake-like body and a lizard-like head”.

“This thing quite probably would have had small legs,” the BBC quoted Dr Longrich as saying.

The ancient reptile’s small size, along with physical features of its spine, suggests that it burrowed. And analysis of its jaws revealed that it fed on relatively large, soft-bodied prey.

But they did not have the flexible jaws that allow modern-day snakes to swallow prey many times their own body size.

“The genesis of the Serpentes (the biological name that defines what we understand as snakes) that began with the evolution of a novel means of locomotion, followed by adaptations facilitating the ingestion of ever larger prey, thereby enabling snakes to exploit a wider range of ecological niches,” the researchers wrote.

The study appears in the journal Nature.

Fossil Critter Pee Reveals Past Climate Change

March 7th, 2013

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But that’s nothing to Brian Chase, a researcher at Montpelier University in France. Chase prefers pee of a somewhat older vintage: the crystallized pee of the rock hyrax (Procavia capensis) that dates to some 55,000 years ago.

Chase uses the information gathered from crystallized hyrax pee in southern Africa to study Earth’s climate thousands of years ago. Not only does this data give scientists a better idea of what the planet was like back then, it also helps them better understand how Earth’s climate is currently changing and what might happen in the future.

For instance, new analysis of the pee reveals that, as Arctic glaciers melted at the end of the last Ice Age around 12,000 years ago, temperatures in southern Africa warmed dramatically, Chase said during the annual meeting of the American Association for the Advancement of Science in Boston earlier this month.

His previous data had found that the Southern Hemisphere was drier than predicted by climate models following dramatic climate changes around 5,500 years ago.

A well-suited scientist displays hyrax pee outside a midden. Photograph courtesy Brian Chase

In a study published in 2011 the journal Geology, his team found that when the Northern Hemisphere warms, the extreme Southern Hemisphere cools, and vice versa.

“This has important implications for our understanding of how the earth system operates, and how we can expect it to respond to different forces, both in the past and the future,” he said.

Layers of Pee

Cute, cuddly critters that are roughly the size of rabbits, hyraxes eat mostly leaves and grasses and are found across Africa and the Middle East. Despite their small sizes, they are the closest living ancestors to elephants and sea cows.

What makes hyraxes useful to scientists are their peculiar bathroom habits. A group of hyraxes will urinate and defecate in the same place, known as a midden, for generations at a time. (More pee news:

Because hyraxes live in relatively dry areas, their bodies help to conserve water by making their urine fairly thick and sticky. This stickiness means that pollen and plant material can become trapped in the hyrax pee as it dries. Generation upon generation of hyraxes all pee in the same place, sometimes for tens of thousands of years.

Each generation of hyrax creates its own new layer of pee that captures the local pollen and plants as it dries. In some of the oldest and largest middens, the crystallized pee forms a structure that is 67 inches (170 centimeters) high—providing a wealth of data for scientists.

“This exceptionally high accumulation rate … means we will be able to get a subdecadal record of environmental change spanning much of the Holocene,” which refers to the last 11,700 years of Earth’s history, Chase told Weird & Wild.

Unlocking Pee’s Secrets

To study ancient climates, scientists generally study the traces of plant material found in soil samples from lakes, bogs, and other soggy grounds.

The wetness in these areas prevents the full decomposition of plants, which means scientists can identify them thousands of years later. Southern Africa, however, has been historically quite arid. So, without lakes and streams from which to gather samples, researchers have had to guess at what the ancient climate was like.

Crystallized hyrax pee, however, changes that.

For one, Chase and others can now use the chemical signatures in the pee to get an idea of what the hyraxes ate when they were alive.

As well the tiny pieces of debris and pollen frequently found trapped in the ancient pee can tell scientists what types of plants were nearby.

This is useful because knowing what plants lived at the time can give researchers a good idea of what the climate must have been like. Some plants, like grasses, need lots of water to survive, while other plants are much more drought-resistant. The chemical signatures of water the plants “drank” while alive also give scientists an idea of how wet the area was.

That’s because hydrogen in the ancient water has different isotopes—or different masses—that can tell scientists what kind of precipitation was present at the time. For instance, if the team were to find a lighter isotope, that would indicate a rainy environment.

Taking the Piss

Getting to the hyrax pee, however, poses its own unique set of problems. Hyrax middens are frequently hidden behind sheer rock faces and in some very tight quarters. While it’s good for the samples—being that sheltered means the pee doesn’t wash away if it rains—it’s difficult for the scientists to access.

Chase, an avid rock climber, puts his skills to good use scaling rock walls. Then, he uses a variety of power tools to grab some samples of the crystallized pee to take back to the lab.

“Once we have found a good layer of solid urine, we dig out samples and remove them for study,”

“We are taking the piss, quite literally—and it is proving to be a highly effective way to study how climate changes have affected local environments.”

Volcano location could be greenhouse-icehouse key

March 5th, 2013

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A new Rice University-led study finds the real estate mantra “location, location, location” may also explain one of Earth’s enduring climate mysteries. The study suggests that Earth’s repeated flip-flopping between greenhouse and icehouse states over the past 500 million years may have been driven by the episodic flare-up of volcanoes at key locations where enormous amounts of carbon dioxide are poised for release into the atmosphere.

Cin-Ty Lee

“We found that Earth’s continents serve as enormous ‘carbonate capacitors,’” said Rice’s Cin-Ty Lee, the lead author of the study in this month’s GeoSphere. “Continents store massive amounts of carbon dioxide in sedimentary carbonates like limestone and marble, and it appears that these reservoirs are tapped from time to time by volcanoes, which release large amounts of carbon dioxide into the atmosphere.”

Lee said as much as 44 percent of carbonates by weight is carbon dioxide. Under most circumstances that carbon stays locked inside Earth’s rigid continental crust.

“One process that can release carbon dioxide from these carbonates is interaction with magma,” he said. “But that rarely happens on Earth today because most volcanoes are located on island arcs, tectonic plate boundaries that don’t contain continental crust.”

Earth’s climate continually cycles between greenhouse and icehouse states, which each last on timescales of 10 million to 100 million years. Icehouse states — like the one Earth has been in for the past 50 million years — are marked by ice at the poles and periods of glacial activity. By contrast, the warmer greenhouse states are marked by increased carbon dioxide in the atmosphere and by an ice-free surface, even at the poles. The last greenhouse period lasted about 50 million to 70 million years and spanned the late Cretaceous, when dinosaurs roamed, and the early Paleogene, when mammals began to diversify.

This diagram illustrates how fluctuations between continental-arc states and island-arc states could lead to episodic deposition and purging of carbon dioxide in Earth’s continental crust.

Lee and colleagues found that the planet’s greenhouse-icehouse oscillations are a natural consequence of plate tectonics. The research showed that tectonic activity drives an episodic flare-up of volcanoes along continental arcs, particularly during periods when oceans are forming and continents are breaking apart. The continental arc volcanoes that arise during these periods are located on the edges of continents, and the magma that rises through the volcanoes releases enormous quantities of carbon dioxide as it passes through layers of carbonates in the continental crust.

Lee, professor of Earth science at Rice, led the four-year study, which was co-authored by three Rice faculty members and additional colleagues at the University of Tokyo, the University of British Columbia, the California Institute of Technology, Texas A&M University and Pomona College.

Lee said the study breaks with conventional theories about greenhouse and icehouse periods.

“The standard view of the greenhouse state is that you draw carbon dioxide from the deep Earth interior by a combination of more activity along the mid-ocean ridges — where tectonic plates spread — and massive breakouts of lava called ‘large igneous provinces,’” Lee said. “Though both of these would produce more carbon dioxide, it is not clear if these processes alone could sustain the atmospheric carbon dioxide that we find in the fossil record during past greenhouses.”

Lee is a petrologist and geochemist whose research interests include the formation and evolution of continents as well as the connections between deep Earth and its oceans and atmosphere..

Lee said the conclusions in the study developed over several years, but the initial idea of the research dates to an informal chalkboard-only seminar at Rice in 2008. The talk was given by Rice oceanographer and study co-author Jerry Dickens, a paleoclimate expert; Lee and Rice geodynamicist Adrian Lenardic, another co-author, were in the audience.

A new Rice University-led study examines whether continental-arc volcanoes like Mount Etna in Sicily may have produced high levels of carbon dioxide during long greenhouse periods in Earth’s ancient past.

“Jerry was talking about seawater in the Cretaceous, and he mentioned that 93.5 million years ago there was a mass extinction of deepwater organisms that coincided with a global marine anoxic event — that is, the deep oceans became starved of oxygen,” Lee said. “Jerry was talking about the impact of anoxic conditions on the biogeochemical cycles of trace metals in the ocean, but I don’t remember much else that he said that day because it had dawned on me that 93 million years ago was a very interesting time for North America. There was a huge flare-up of volcanism along the western margin of North America, and the peak of all this activity was 93 million years ago.

“I thought, ‘Wow!’” Lee recalled. “I know coincidence doesn’t mean causality, but it certainly got me thinking. I decided to look at whether the flare-up in volcanic activity that helped create the Sierra Nevada Mountains may also have affected Earth’s climate.”

Over the next two years, Lee developed the idea that continental-arc volcanoes could pump carbon dioxide into the atmosphere. One indicator was evidence from Mount Etna in Sicily, one of the few active continental-arc volcanoes in the world today. Etna produces large amounts of carbon dioxide, Lee said, so much that it is often considered an outlier in global averages of modern volcanic carbon dioxide production.

Tectonic and petrological evidence indicated that many Etna-like volcanoes existed during the Cretaceous greenhouse, Lee said. He and colleagues traced the likely areas of occurrence by looking for tungsten-rich minerals like scheelite, which are formed on the margins of volcanic magma chambers when magma reacts with carbonates. It wasn’t easy; Lee spent an entire year pouring through World War II mining surveys from the western U.S. and Canada, for example.

“There is evidence to support our idea, both in the geological record and in geophysical models, the latter of which show plausibility,” he said. For example, in a companion paper published last year in G-Cubed, Lenardic used numerical models that showed the opening and breakup of continents could change the nature of subduction zones, generating oscillations between continental- and island-arc dominated states.

Though the idea in the GeoSpheres study is still a theory, Lee said, it has some advantages over more established theories because it can explain how the same basic set of geophysical conditions could produce and sustain a greenhouse or an icehouse for many millions of years.

“The length of subduction zones and the number of arc volcanoes globally don’t have to change,” Lee said. “But the nature of the arcs themselves, whether they are continental or oceanic, does change. It is in the continental-arc stage that CO2 is released from an ever-growing reservoir of carbonates within the continents.”

Rice co-authors include Dickens and Lenardic, both professors of Earth science; Rajdeep Dasgupta, assistant professor of Earth science; Bing Shen, postdoctoral research associate; Benjamin Slotnick, graduate student; and Kelley Liao, a graduate student who began work on the project as undergraduate. Additional co-authors include Yusuke Yokoyama of the University of Tokyo, Mark Jellinek of the University of British Columbia, Jade Star Lackey of Pomona College, Tapio Schneider of Caltech and Michael Tice of Texas A&M. The research was supported by the Packard Foundation, the Atmosphere and Ocean Research Institute at the University of Tokyo, the National Science Foundation and the Miller Institute at the University of California, Berkeley.

source link: http://news.rice.edu/2013/02/06/volcano-location-could-be-greenhouse-icehouse-key-2/

WFS Profiles: Luis Alvarez 1911 – 1988

March 4th, 2013

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Luis Alvarez and son Walter near Gubbio, Italy

Photo Courtesy :LBNL Image Library — Collection BERKELEY-LAB/PEOPLE/INDIVIDUALS

Luis Alvarez was a physicist with wide ranging interests. At the University of Chicago, he took a class called Advanced Experimental Physics: Light, and later claimed, “It was love at first sight.” He graduated in 1932 and stayed at Chicago for his graduate work. He married, had two kids, and moved to Berkeley, where he worked with Ernest Lawrence and stayed until 1978.

Alvarez’s colleagues sometimes called him the “prize wild idea man” because of the huge range of his activities. He did all kinds of research into the atomic nucleus, light, electrons, radar, and so forth. In 1943 he was part of the Manhattan Projectin Los Alamos and developed a detonating device for the atomic bomb. He was on board the bomber Enola Gay when it dropped the bomb on Hiroshima. Alvarez was shocked and sickened by what he saw, but because the war ended so soon afterwards, he never expressed doubts about the bomb’s use. In fact, he was one of few scientists who had worked on the bomb who felt the U.S. should continue weapons development and make a hydrogen bomb. He continued to do varied work in high energy physics and in 1968, received the Nobel Prize.

In 1965 Alvarez took his physics expertise on an archeological expedition. A U.S.-Egyptian team was trying to find hidden chambers in the Giza pyramid in Egypt by using subatomic particles to calculate the pyramid’s density. They didn’t find any chambers, but this began Alvarez’s work with his son Walter, a geology professor at Berkeley. Together they developed a theory in 1980 that a Giant Asteroid striking Earth had killed off the dinosaurs around 65 million years ago. They had strong geologic evidence, but the theory is still being debated.

Alvarez’s other claims to fame are in assisting the Warren Commission that investigated the assasination of President Kennedy and holding 22 patents, including an indoor golf-training machine he developed for President Eisenhower. Alvarez died of cancer in 1988.

Prehistoric colours in fossil insects

March 4th, 2013

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An international research team led by a University of Bristol scientist has explained the preservation of colours in fossil insects for the first time.

The discovery explains why colours change and why they are destroyed during fossilisation, revealing hidden gems in the insect fossil record that could help reconstruct the evolution of colours in insects.

The paper has just been published online in the journal Geology. The research will also be showcased at this year’s prestigious Royal Society Summer Science Exhibition in London, from 1 to 7 July.

Many modern insects owe their brilliant colours to microscopic light-reflecting structures in their tissues, but the fossil record of these ‘structural colours’ is patchy. Even where these colours are fossilised, the original colours change during the fossilisation process.

The iridescent jewel beetle Chrysochroa raja owes its colour to nanometre-size structures in its outer tissues and was used in fossilisation experiments to explain patterns in the fossil record of colour

Dr Maria McNamara, a Research Assistant in Palaeobiology from the School of Earth Sciences, led a team of researchers from Yale University and University College Dublin which used a novel experimental technique to simulate high pressures and temperatures that are found deep under the Earth’s surface.

The team used modern beetles and discovered that they changed colour during the experiments due to changes in the chemistry and physical architecture of the colour-producing structures in their tissues.

Dr McNamara said: “Our results explain a big mystery in the field of fossil colour. By looking at what happens to structural colours in modern insects during fossilisation experiments, we can now say exactly why and how structural colours change during the burial process. Now we know what key events in the geological history of sediments can cause colour change. This will help us to pin down which fossils show colours that we can trust, and which have been altered.

“Our results also provide compelling evidence for why certain types of structural colours – produced by complex 3D organic crystal lattices called 3D photonic crystals – aren’t found in the fossil record. Rather than simply not being preserved, our experiments show that these structures are really tough and can survive the same burial conditions as other structural colours. This indicates that 3D photonic crystals, which are the most complex colour-producing structures known in nature, evolved extremely recently – within the last few million years.”

The research was carried out at Yale University and was supported by a Marie Curie International Mobility Fellowship through University College Dublin, awarded to Dr McNamara.

research work: ‘The fossil record of insect colour illuminated by maturation experiments’, by Maria McNamara, Derek Briggs, Patrick Orr, Neal Gupta, Emma Locatelli, Lin Qiu, Hong Yang, Zhengrong Wang, Heeso Noh and Hui Cao published in Geology.

WFS Dinosaur Diary: Argentinosaurus

March 3rd, 2013

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Argentinosaurus is a genus of titanosaur sauropod dinosaur first discovered by Guillermo Heredia in Argentina. The generic name refers to the country in which it was discovered. The dinosaur lived on the then-island continent of South America somewhere between 97 and 94 million years ago, during the Late Cretaceous Epoch.

Reconstructed skeleton of Argentinosaurus huinculensis at the Naturmuseum Senckenberg in Frankfurt, Germany

The type species of Argentinosaurus, A. huinculensis, was described and published in 1993 by the Argentinian palaeontologists José F. Bonaparte and Rodolfo Coria. Its more specific time-frame within the Cretaceous is the late Cenomanian faunal stage, ~96 to 94 million years ago. The fossil discovery site is in the Huincul Formation of the Río Limay Subgroup in Neuquén Province, Argentina (the Huincul Formation was a member of the Río Limay Formation according to the naming of the time)

Argentinosaurus femur, Museo de La Plata.

Not much of Argentinosaurus has been recovered. The holotype included three anterior dorsal vertebrae, three posterior dorsal vertebrae, first to fifth sacrum vertebrae (only the ventral sector of the vertebral bodies), most of the sacral ribs of the right side, great part of a fragmented dorsal rib, and the right tibia. One vertebra had a length of 1.59 meters (spine to the ventral border) and the tibia was about 155 centimeters (58 inches).^[1] Besides these, an incomplete femur (MLP-DP 46-VIII-21-3) is assigned to Argentinosaurus; this incomplete femur shaft has a minimal circumference of about 1.18 meters.^[2] The proportions of these bones and comparisons with other sauropod relatives allow paleontologists to estimate the size of the animal.

Source: Wikipedia

Dinosaurian Soft Tissues Interpreted as Bacterial Biofilms: Research by Thomas G. Kaye , Gary Gaugler, Zbigniew Sawlowicz

March 2nd, 2013

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A scanning electron microscope survey was initiated to determine if the previously reported findings of “dinosaurian soft tissues” could be identified in situ within the bones. The results obtained allowed a reinterpretation of the formation and preservation of several types of these “tissues” and their content. Mineralized and non-mineralized coatings were found extensively in the porous trabecular bone of a variety of dinosaur and mammal species across time. They represent bacterial biofilms common throughout nature. Biofilms form endocasts and once dissolved out of the bone, mimic real blood vessels and osteocytes. Bridged trails observed in biofilms indicate that a previously viscous film was populated with swimming bacteria. Carbon dating of the film points to its relatively modern origin. A comparison of infrared spectra of modern biofilms with modern collagen and fossil bone coatings suggests that modern biofilms share a closer molecular make-up than modern collagen to the coatings from fossil bones. Blood cell size iron-oxygen spheres found in the vessels were identified as an oxidized form of formerly pyritic framboids. Our observations appeal to a more conservative explanation for the structures found preserved in fossil bone.

Materials and Methods

Scanning electron microscopes used were JEOL T300, Zeiss Supra and Cambridge S200. Light microscopes were Zeiss Axiomat, Nikon SMZ-U and Unitron. EDS spectra were taken with Kevex Delta 5, EDAX Apollo 40 running under EDAX Genesis/Pegasus and Link LZ5 running under WinEDS.

SEM specimens were prepared by pressure fracturing and selected pieces approximately 10 mm square were fixed to aluminum stubs with high purity carbon tabs. Initial specimens were uncoated to minimize potential disruption of internal contents. Subsequent specimens were gold coated with a Bio-Rad E5000 sputter coater or Denton Desk IV turbo coater with Pd or Pt target. Low dot-pitch element maps were run at 15 kV. The maps of individual elements were combined with a high-resolution secondary electron images to produce a high resolution colored element maps.

Modern biofilms were grown with the following method. Two gallons of water obtained from a local pond was placed in a new five gallon bucket and recirculated with a small pump at room temperature. Five new microscope slides were placed in the bottom with 100 mg of glucose nutrient added to the water. Water samples were taken every two days to monitor microbe population. One slide was removed and examined under the light microscope every few days to monitor biofilm accumulation rate. Slides were allowed to desiccate at room temperature over several days. Microbial communities could clearly be seen in the hydrated biofilms under the light microscope but subsequent examination under SEM showed only a smooth undulating profile.

Fourier Transform Infrared Spectroscopy (FT-IR) was used to investigate the specimens’ molecular structure. A turtle carapace from the Hell Creek formation was selected for spectroscopy because of its proportionally large chambers in the trabecular bone that allowed scraping the coatings loose. Two milligrams of material was ground with 450 milligrams of potassium bromide (KBr) and pressed into a pellet using 8 tons pressure. Modern biofilms grown on microscope slides in pond water were allowed to desiccate for 7 days and 2.5 milligrams were pressed into a KBr pellet as above. A 2.5 milligram sample of desiccated tendon from a chicken was ground with KBr and pelletized. Spectrums were taken on a Nicolet 510P bench at 1 cm⁻¹ resolution with a minimum of 15 scans. Infrared flux was matched within 5% for all specimens and a clean KBr pellet used for background subtraction between specimens. Excel cross correlation routines were used to determine percentage of similarity for spectrums.

Framboids were individually extracted from fractured dinosaur bone fragments with a magnet and transferred to a carbon sticky tab on an SEM stub. EDS was performed on a small section of the sphere at 20 kV in the area shown with the spectrum in figure 1.

Figure 1. EDS spectrum of framboid.

EDS spectrum of framboid showing an iron-oxygen signature. Pt is from coating for SEM. Area in red box was scanned for elements.

Multiple specimens were pressure fractured and 10–20 mm fragments selected for demineralization in 0.5 M ethylenediaminetetraacetic acid (EDTA) (pH 8.0) in individual plastic containers at room temperature. Resident times ranged from several days to several weeks depending on specimen resistance. Baths were changed at approximately three day intervals with fresh acid. Remaining structures were either photographed directly in the baths at low magnification 7–75× or removed for higher power imaging.

All specimens for carbon dating were handled under a flow hood with clean sterile gloves and instruments. The specimens were pressure fractured to reveal fresh surfaces. A bone fragment from the Lance formation was microscopically examined and coatings that appeared to have been dislodged were removed for analysis. Fifty milligrams of material were sent to Geochron Labs, Cambridge Mass. for accelerator mass spectrometry (AMS) analysis. The results were 139.01%±0.65 of modern (1950) of ¹⁴C activity.

Figure 2. Well preserved complete bone used in initial investigation.

Exceptionally well preserved small phalange from the Lance formation used for initial survey. No cracks or deformities present. Specimen was pressure fractured and directly examined under the SEM. UWBM 89327 Scale bar, 10 mm.

Figure 3. Iron oxide framboids.

An iron oxide framboid cluster in dinosaur trabecular bone found commonly throughout time and taxa. At approximately 10 microns in diameter they are closely matched in size to red blood cells and typical pyrite framboids. UWBM 89327 Scale bar, 3 µm.

Citation: Kaye TG, Gaugler G, Sawlowicz Z (2008) Dinosaurian Soft Tissues Interpreted as Bacterial Biofilms. PLoS ONE 3(7): e2808. doi:10.1371/journal.pone.0002808

Editor: Anna Stepanova, Paleontological Institute, Russian Federation

Feeding Limbs and Nervous System of One of Earth’s Earliest Animals Discovered

March 1st, 2013

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An extraordinary find allowing scientists to see through the head of the ‘fuxianhuiid’ arthropod has revealed one of the earliest evolutionary examples of limbs used for feeding, along with the oldest nervous system to stretch beyond the head in fossil record.

Until now, all fossils found of this extremely early soft-bodied animal featured heads covered by a wide shell or ‘carapace’, obscuring underlying contents from detailed study.

Chenjiangocaris kunmingensis arthropod from the early Cambrian Xiaoshioba biota and a reconstruction. (Credit: Yie Jang and Javier Ortega-Hernández)

But a new fossil-rich site in South China has been found to contain arthropod examples where the carapace has literally been ‘flipped’ over before fossilisation — allowing scientists to examine the fuxianhuiid head to an unprecedented extent.

The study, published today in Nature, highlights the discovery of previously controversial limbs under the head, used to shovel sediment into the mouth as the fuxianhuiid crawled across the seabed, millions of years before creatures emerged from the oceans.

Scientists say that this could be the earliest and simplest example of manipulative limbs used for feeding purposes, hinting at the adaptive ability that made arthropods so successful and abundant — evolving into the insects, spiders and crustaceans we know today.

Using a feeding technique scientist’s call ‘detritus sweep-feeding’, fuxianhuiids developed the limbs to push seafloor sediment into the mouth in order to filter it for organic matter — such as traces of decomposed seaweed — which constituted the creatures’ food.

Fossils also revealed the oldest nervous system on record that is ‘post-cephalic’ — or beyond the head — consisting of only a single stark string in what was a very basic form of early life compared to today.

“Since biologists rely heavily on organisation of head appendages to classify arthropod groups, such as insects and spiders, our study provides a crucial reference point for reconstructing the evolutionary history and relationships of the most diverse and abundant animals on Earth,” said Javier Ortega-Hernández, from Cambridge’s Department of Earth Sciences, who produced the research with Dr Nicholas Butterfield and colleagues from Yunnan University in Kunming, South China. “This is as early as we can currently see into arthropod limb development.”

Fuxianhuiids existed around 520 million years ago, roughly 50 million years before primordial land animals crawled from the sea, and would have been one of the first examples of complex animal life — likely to have evolved from creatures resembling worms with legs. Arthropods were the first jointed animals, enabling them to crawl.

Fuxianhuiid arthropods would have spent most of their time grazing on the sea floor, using these newly discovered limbs to plow sediment into their mouths. They could probably also use their bodies to swim for short distances, like tadpole shrimps.

The fossils date from the early part of the event known as the ‘Cambrian explosion’, when life on Earth went from multi-cellular organisms we know very little about to a relatively sudden and wide spread explosion of diverse marine animals — the first recognisable evolutionary step for the animal kingdom we know today.

“These fossils are our best window to see the most primitive state of animals as we know them — including us,” said Ortega-Hernández. “Before that there is no clear indication in the fossil record of whether something was an animal or a plant — but we are still filling in the details, of which this is an important one.”

While still a mystery, theories about the cause of the ‘Cambrian Explosion’ include possible correlations with oxygen rises, spikes in oceanic nutrient concentration, and genetic complexity reaching critical mass.

But the new site in South China where these fossils were found could prove to be key in uncovering ever more information about this pivotal period in the history of life on Earth. The Xiaoshiba ‘biota’ — that is the collection of all organisms preserved in the new locality — in China’s Yunnan Province is similar to the world-famous Chengjiang biota, which provided many of the best arthropod fossil records to date.

“The Xiaoshiba biota is amazingly rich in such extraordinary fossils of early organisms,” said Ortega-Hernández. “Over 50 specimens of fuxianhuiids have been found in just over a year, whereas previous areas considered fossil rich such as Chengjiang it took years — even decades — to build up such a collection.”

“So much material is so well preserved. There’s massive potential for Xiaoshiba to become a huge deal for new discoveries in early animal evolution.”