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

Great Karoo rocks reveals mass extinction

July 8th, 2015

Riffin

An international team led by researchers from the Evolutionary Studies Institute (ESI) at the University of the Witwatersrand, Johannesburg, has obtained an age from rocks of the Great Karoo that shed light on the timing of a mass extinction event that occurred around 260 million years ago.

WFS : Great Karoo ,South Africa

This led to the disappearance of a diverse group of early mammal-like reptiles called dinocephalians, which were the largest land-living animals of the time.

The project was led by Dr Michael Day, a postdoctoral fellow at Wits University, and the findings are contained in paper, titled: When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa, published today, 8 July 2015, in the latest issue of the Royal Society’s biological journal, Proceedings of the Royal Society B.

This is an illustration of the Guadalupian extinction.
Credit: Wits University

The Karoo is very rich in fossils of terrestrial animals from the Permian and Triassic geological periods, which makes it one of the few places to study extinction events on land during this time. As a result South Africa’s Karoo region provides not only a historical record of biological change over a period of Earth’s history but also a means to test theories of evolutionary processes over long stretches of time.

By collecting fossils in the Eastern, Western and Northern Cape Provinces the team was able to show that around 74-80% of species became extinct along with the dinocephalians in a geologically short period of time.

The new date was obtained by high precision analyses of the relative abundance of uranium and lead in small zircon crystals from a volcanic ash layer close to this extinction horizon in the Karoo.

This provides a means of linking the South African fossil record with the fossil record in the rest of the world. In particular, it helps correlate the Karoo with the global marine record, which also records an extinction event around 260 million years ago.

“A mid-Permian extinction event on land has been known for some time but was suspected to have occurred earlier than those in the marine realm. The new date suggests that one event may have affected marine and terrestrial environments at the same time, which could mean its impact was greater than we thought,” says Day.

The mid-Permian extinction occurred near the end of what geologists call the Guadalupian epoch that extended from 272.3 to around 259.1 million years ago. It pre-dated the massive and much more famous end-Permian mass extinction event by 8 million years.

“The South African Karoo rocks host the richest record of middle Permian land-living vertebrate animals. This dataset, the culmination of 30 years of fossil collecting and diligent stratigraphic recording of the information, for the first time provides robust fossil and radioisotopic data to support the occurrence of this extinction event on land,” says Day.

“The exact age of the marine extinctions remains uncertain,” says Jahandar Ramezani of Massachusetts Institute of Technology and who was responsible for dating the rocks, “but this new date from terrestrial deposits of the Karoo, supported by palaeontological evidence, represents an important step towards a better understanding of the mid-Permian extinction and its effect on terrestrial faunas.”

REF: Michael O. Day, Jahandar Ramezani, Samuel A. Bowring, Peter M. Sadler, Douglas H. Erwin, Fernando Abdala, Bruce S. Rubidge. When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa. Proceedings of the Royal Society B, Courtesy:ScienceDaily, 7 July 2015.

Ground-based atomic clocks for monitoring volcanoes

July 5th, 2015

Riffin

An international team led by scientists from the University of Zurich finds that high-precision atomic clocks can be used to monitoring volcanoes and potentially improve predictions of future eruptions. In addition, a ground-based network of atomic clocks could monitor the reaction of Earth’s crust to solid Earth tides.

Atomic clocks measure time with unbelievable accuracy. The best atomic clocks are so precise that they would lose less than one second over a period of 10 billion years. However, they are generally only used in laboratories. Science and industry have yet to take full advantage of their unprecedented ability to measure time. An international team including Dr. Ruxandra Bondarescu, Andreas Schärer and Prof. Philippe Jetzer from the Institute of Physics from the University of Zurich discusses potential applications for atomic clocks.

Subterranean objects influence the tick rate of local clocks that are located above the Earth’s surface. New lava filling a magma chamber beneath a volcano makes a clock located above that volcano tick more slowly than a clock that is located further away.

Their analysis shows that the slow down of time predicted by general relativity can be measured by local clocks and used to monitor volcanoes. General relativity states that clocks positioned at different distances from a massive body like Earth have different tick rates. The closer a clock is to a massive object, the slower it ticks. In a similar manner, subterranean objects influence the tick rate of local clocks that are located above Earth’s surface. New lava filling a magma chamber beneath a volcano makes a clock located above that volcano tick more slowly than a clock that is located further away. Volcanoes are currently monitored using GPS receivers. The resulting data often has to be integrated over a period of several years before an estimate of the volume of new magma can be made. A network of local, highly precise atomic clocks may provide the same information within a few hours. This would make it possible to monitor processes inside volcanoes more closely and to make better predictions for future volcanic eruptions.

Monitoring the solid Earth tides with a global network of atomic clocks

Atomic clocks can also be used to monitor the solid Earth tides. Tides occur because Earth moves in the gravitational field of the Sun and the Moon. It reacts to this outer field by deforming, which in turn leads to ocean tides and to the ground on the continents lifting and falling regularly. The ground can rise as much as 50 cm. A global network of atomic clocks that are connected via fiber optic cables used for internet, could provide continuous measurements of Earth tides and check existing theoretical models. It would also be possible to examine any local differences in the response of Earth’s crust to Earth tides.

The researchers hope that high precision clocks could be deployed in volcanic areas in the next few years. This is, however, subject to sufficient interest and investment from industry. “We need this additional tool to monitor magma movement under volcanoes such as the Yellowstone supervolcano, which is overdue for an explosion that would alter life on Earth as we known it,” explains Bondarescu.

REf: Ruxandra Bondarescu, Andreas Schärer, Andrew P. Lundgren, György Hetényi, Nicolas Houlié, Philippe Jetzer, and Mihai Bondarescu. Atomic Clocks as a Tool to Monitor Vertical Surface Motion. Geophysical Journal International, June 2015

A New Eocene Casquehead Lizard from North America

July 3rd, 2015

Riffin

A new fossil showing affinities with extant Laemanctus offers the first clear evidence for a casquehead lizard (Corytophanidae) from the Eocene of North America. Along with Geiseltaliellus from roughly coeval rocks in central Europe, the new find further documents the tropical fauna present during greenhouse conditions in the northern mid-latitudes approximately 50 million years ago (Ma). Modern Corytophanidae is a neotropical clade of iguanian lizards ranging from southern Mexico to northern South America.

Citation: Conrad JL (2015) A New Eocene Casquehead Lizard (Reptilia, Corytophanidae) from North America. PLoS ONE 10(7): e0127900. doi:10.1371/journal.pone.0127900

Academic Editor: Ulrich Joger, State Natural History Museum, GERMANY

Photographs (A-C) and line drawings (D-F) of the skulls of selected corytophanid species in left lateral view.
(A) Corytophanes cristatus (AMNH R 16390), (B) Laemanctus serratus (photograph; AMNH R 44982), (C) Basiliscus vittatus (AMNH R 147832), (D) Laemanctus serratus (line drawing), (E) Geiseltaliellus maarius, and (F) Babibasiliscus alxi taxon nov. (UWBM 89090). Note that it is unclear whether Babibasiliscus alxi taxon nov. had a parietal crest. Reconstructed areas are represented as semi-opaque areas and/or dotted lines. Scale bars equal 10mm.
doi:10.1371/journal.pone.0127900.g005

Holotype (UWBM 89090) specimen for Babibasiliscus alxi nov. taxon.
Photographs in (A) right lateral, (B) dorsal, and (C) ventral views. Digital reconstructions derived from HRXCT in (D) left lateral view and (E) transverse section. The vertical red line in (D) indicates the plane of section in (E).
doi:10.1371/journal.pone.0127900.g001

Helium leakage from Earth’s mantle ?

June 30th, 2015

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UC Santa Barbara geologist Jim Boles has found evidence of helium leakage from Earth’s mantle along a 30-mile stretch of the Newport-Inglewood Fault Zone in the Los Angeles Basin. Using samples of casing gas from two dozen oil wells ranging from LA’s Westside to Newport Beach in Orange County, Boles discovered that more than one-third of the sites — some of the deepest ones — show evidence of high levels of helium-3 (3He).

Considered primordial, 3He is a vestige of the Big Bang. Its only terrestrial source is the mantle. Leakage of 3He suggests that the Newport-Inglewood fault is deeper than scientists previously thought. Boles’s findings appear in Geochemistry, Geophysics, Geosystems (G-Cubed), an electronic journal of the American Geophysical Union and the Geochemical Society.

The Newport-Inglewood fault was responsible for the 4.9 magnitude Inglewood earthquake in 1920 and the 6.4 magnitude Long Beach earthquake in 1933.
Credit: Sonia Fernandez

“The results are unexpected for the area, because the LA Basin is different from where most mantle helium anomalies occur,” said Boles, professor emeritus in UCSB’s Department of Earth Science. “The Newport-Inglewood fault appears to sit on a 30-million-year-old subduction zone, so it is surprising that it maintains a significant pathway through the crust.”

When Boles and his co-authors analyzed the 24 gas samples, they found that high levels of 3He inversely correlate with carbon dioxide (CO₂), which Boles noted acts as a carrier gas for 3He. An analysis showed that the CO₂ was also from the mantle, confirming leakage from deep inside Earth.

Blueschist found at the bottom of nearby deep wells indicates that the Newport-Inglewood fault is an ancient subduction zone — where two tectonic plates collide — even though its location is more than 40 miles west of the current plate boundary of the San Andreas Fault System. Found 20 miles down, blueschist is a metamorphic rock only revealed when regurgitated to the surface via geologic upheaval.

“About 30 million years ago, the Pacific plate was colliding with the North American plate, which created a subduction zone at the Newport-Inglewood fault,” Boles explained. “Then somehow that intersection jumped clear over to the present San Andreas Fault, although how this occurred is really not known. This paper shows that the mantle is leaking more at the Newport-Inglewood fault zone than at the San Andreas Fault, which is a new discovery.”

The study’s findings contradict a scientific hypothesis that supports the existence of a major décollement — a low-angle thrust fault — below the surface of the LA Basin. “We show that the Newport-Inglewood fault is not only deep-seated but also directly or indirectly connected with the mantle,” Boles said.

“If the décollement existed, it would have to cross the Newport-Inglewood fault zone, which isn’t likely,” he added. “Our findings indicate that the Newport-Inglewood fault is a lot more important than previously thought, but time will tell what the true importance of all this is.”

Study co-authors include Grant Garven of Tufts University; Hilario Camacho of Occidental Oil and Gas Corp.; and John Lupton of the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory.

This research was supported by the U.S. Department of Energy’s Office of Science and Office of Basic Energy Sciences and by the NOAA Pacific Marine Environmental Laboratory.

Courtesy: University of California – Santa Barbara. “Helium leakage from Earth’s mantle in Los Angeles Basin: New discoveries about Newport-Inglewood Fault Zone in Los Angeles Basin.” ScienceDaily. ScienceDaily, 29 June 2015.

Sefapanosaurus — SA’s new Sesotho dinosaur.

June 26th, 2015

Riffin

South African and Argentinian palaeontologists have discovered a new 200-million-year-old dinosaur from South Africa, and named it Sefapanosaurus, from the Sesotho word “sefapano.”

The researchers from South Africa’s University of Cape Town (UCT) and the University of the Witwatersrand (Wits University), and from the Argentinian Museo de La Plata and Museo Paleontológico Egidio Feruglio made the announcement in the scientific journal Zoological Journal of the Linnaean Society. The paper, titled: “A new basal sauropodiform from South Africa and the phylogenetic relationships of basal sauropodomorphs,” was published online on Tuesday, 23 June 2015.

Sefapanosaurus — SA’s new Sesotho dinosaur.
Credit: Image courtesy of University of the Witwatersrand

The specimen was found in the late 1930s in the Zastron area of South Africa’s Free State province, about 30km from the Lesotho border. For many years it remained hidden among the largest fossil collection in South Africa at the Evolutionary Studies Institute (ESI) at Wits University.

A few years ago it was studied and considered to represent the remains of another South African dinosaur, Aardonyx. However, upon further study, close scrutiny of the fossilised bones has revealed that it is a completely new dinosaur.

One of the most distinctive features is that one of its ankle bones, the astragalus, is shaped like a cross. Considering the area where the fossil was discovered, the researchers aptly named the new dinosaur, Sefapanosaurus, after the Sesotho word “sefapano,” meaning “cross.”

Anusuya Chinsamy-Turan, co-author and Professor in the Department of Biological Sciences at UCT, says: “The discovery of Sefapanosaurus shows that there were several of these transitional early sauropodomorph dinosaurs roaming around southern Africa about 200 million years ago.”

Dr Alejandro Otero, Argentinian palaeontologist and lead author, says Sefapanosaurus helps to fill the gap between the earliest sauropodomorphs and the gigantic sauropods. “Sefapanosaurus constitutes a member of the growing list of transitional sauropodomorph dinosaurs from Argentina and South Africa that are increasingly telling us about how they diversified.”

Says Dr Jonah Choiniere, co-author and Senior Researcher in Dinosaur Palaeobiology at the ESI at Wits University: “This new animal shines a spotlight on southern Africa and shows us just how much more we have to learn about the ecosystems of the past, even here in our own ‘backyard’. And it also gives us hope that this is the start of many such collaborative palaeo-research projects between South Africa and Argentina that could yield more such remarkable discoveries.”

Argentinian co-author, Dr Diego Pol, says Sefapanosaurus and other recent dinosaur discoveries in the two countries reveal that the diversity of herbivorous dinosaurs in Africa and South America was remarkably high back in the Jurassic, about 190 million years ago when the southern hemisphere continents were a single supercontinent known as Gondwana.

Finding a new dinosaur among old bones

Otero and Emil Krupandan, PhD-student from UCT, were visiting the ESI collections to look at early sauropodomorph dinosaurs when they noticed bones that were distinctive from the other dinosaurs they were studying.

Krupandan was working on a dinosaur from Lesotho as part of his studies when he realised the material he was looking at was different to Aardonyx. “This find indicates the importance of relooking at old material that has only been cursorily studied in the past, in order to re-evaluate past preconceptions about sauropodomorph diversity in light of new data.”

The remains of the Sefapanosaurus include limb bones, foot bones, and several vertebrae. Sefapanosaurus is represented by the remains of at least four individuals in the ESI collections at Wits University. It is considered to be a medium-sized sauropodomorph dinosaur — among the early members of the group that gave rise to the later long necked giants of the Mesozoic.

Alejandro Otero, Emil Krupandan, Diego Pol, Anusuya Chinsamy, Jonah Choiniere. A new basal sauropodiform from South Africa and the phylogenetic relationships of basal sauropodomorphs. Zoological Journal of the Linnean Society, 2015; 174 (3): 589 DOI: 10.1111/zoj.12247

Dinosaur tracks reconstructed

June 24th, 2015

Riffin

Twelve years ago, footprints of carnivorous dinosaurs were discovered and excavated in a quarry near Goslar. Paleontologists from the University of Bonn, working with Dinosaur Park Münchehagen and the State Museum of Hanover, have now created a three-dimensional digital model based on photographs of the excavation. The reconstruction of the discovery site suggests that carnivorous dinosaurs hunted herbivorous island-dwelling dinosaurs about 154 million years ago. They believe the predators could have immigrated via a land bridge as sea levels dropped.

The findings have now been published in the geoscience journal Palaeontologia Electronica.

In 2003, a private fossil collector made a surprising discovery in a limestone quarry near Goslar in Lower Saxony: a total of 20 dinosaur footprints imprinted on a stone slab. Nils Knötschke, from Dinosaur Park Münchehagen, was able to salvage five of the tracks and kept them from being destroyed by the quarry work. Now, about a dozen years later, paleontologists from the University of Bonn, led by Prof. Dr. Martin Sander, have worked with Nils Knötschke and Dr. Oliver Wings from the State Museum of Hanover to reconstruct the tracks in a three-dimensional model, using digital methods. The project was based on photos of the tracks taken at the time when they were excavated.

Three-dimensional model of one of the largest footprint fillings. Left: Color-coded elevation model. Reds represent the highest points in the footprint, and blues represent the lowest points. Right: Three-dimensional model with photorealistic texture.
Credit: Jens Lallensack/2015

“Even five years ago, it wouldn’t have been technically possible to do this kind of reconstruction,” says first author Jens N. Lallensack of the Steinmann Institute for Geology, Mineralogy and Paleontology at the University of Bonn. Based on the 3D model, the researchers were able to gain crucial information about the dinosaurs that left the footprints behind, and about their habitat at the time. The tracks, measuring between 36 and 47 centimeters in length, probably represent two different species of predatory dinosaurs from the Theropoda group.

Glimpses of the habitat 154 million years ago

Based on the digital model, we can now see how the individual footprints are positioned in relation to one another. “That allowed us to reconstruct the moving direction, and how fast the animals were traveling. Based on the length of the footprints, we can estimate that the largest animals had a body length of about eight meters. In some places, the carnivorous dinosaurs also left much deeper tracks in the sediment than elsewhere. “Where the ground was soft, the dinosaurs sank in much deeper than where it was dry,” reports Lallensack.

About 154 million years ago, during the Late Jurassic Era, there was a shallow sea throughout this region, with small islands jutting up out of it. Bones found in the Langenberg Quarry confirm that the islands were inhabited by a species of small dinosaurs, Europasaurus holgeri. These herbivores belonged to the group of gigantic, long-necked dinosaurs called sauropods. However, a full-grown Europasaurus only measured six to eight meters — about one-fourth the length of its nearest relative, Camarasaurus. “The dinosaur probably had to shrink down to dwarf size in order to survive, given the limited food available on these small islands in the shallow Central European sea,” says Lallensack.

Theropods probably immigrated via a land bridge

The theropods that originally made the reconstructed dinosaur tracks came on the scene about 35,000 years later. “It’s possible that the sea level dropped during this period — a relatively short time from a geological perspective — and that the mainland carnivorous dinosaurs immigrated at that point,” surmises Dr. Wings, who is heading a research project funded by VolkswagenStiftung at the State Museum of Hanover on the overall Jurassic habitats of the region. The theropod tracks come from a dried-up ocean floor bed very close to one of the islands.

As a result, the researchers suspect that the predatory theropods came from the mainland in order to hunt the herbivorous Europasaurus. All of the limestone in the quarry formed in a shallow sea basin, as evidenced by the large number of marine fossils such as snails, mussels and sea urchins. To date, the tracks are the only indication that the region was temporarily dry, and that large mainland-based carnivorous dinosaurs were present on the former Europasaurus island. “We suspect that is what sealed the fate of these specialized island-dwelling dwarves,” says Lallensack.

Ref: Jens N. Lallensack, P. Martin Sander, Nils Knötschke, and Oliver Wings. Dinosaur tracks from the Langenberg Quarry (Late Jurassic, Germany) reconstructed with historical photogrammetry: Evidence for large theropods soon after insular dwarfism. Palaeontologia Electronica, 2015: Universität Bonn. “Dinosaur tracks reconstructed.” ScienceDaily. ScienceDaily, 23 June 2015. <www.sciencedaily.com/releases/2015/06/150623072908.htm>.

First sensor of Earth’s magnetic field in an animal

June 21st, 2015

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A team of scientists and engineers at The University of Texas at Austin has identified the first sensor of Earth’s magnetic field in an animal, finding in the brain of a tiny worm a big clue to a long-held mystery about how animals’ internal compasses work.

Animals as diverse as migrating geese, sea turtles and wolves are known to navigate using Earth’s magnetic field. But until now, no one has pinpointed quite how they do it. The sensor, found in worms called C. elegans, is a microscopic structure at the end of a neuron that other animals probably share, given similarities in brain structure across species. The sensor looks like a nano-scale TV antenna, and the worms use it to navigate underground.

Inside the head of the worm C. elegans, the TV antenna-like structure at the tip of the AFD neuron (green) is the first identified sensor for Earth’s magnetic field.
Credit: Illustration by Andres Vidal-Gadea.

“Chances are that the same molecules will be used by cuter animals like butterflies and birds,” said Jon Pierce-Shimomura, assistant professor of neuroscience in the College of Natural Sciences and member of the research team. “This gives us a first foothold in understanding magnetosensation in other animals.”

The researchers discovered that hungry worms in gelatin-filled tubes tend to move down, a strategy they might use when searching for food.

When the researchers brought worms into the lab from other parts of the world, the worms didn’t all move down. Depending on where they were from — Hawaii, England or Australia, for example — they moved at a precise angle to the magnetic field that would have corresponded to down if they had been back home. For instance, Australian worms moved upward in tubes. The magnetic field’s orientation varies from spot to spot on Earth, and each worm’s magnetic field sensor system is finely tuned to its local environment, allowing it to tell up from down.

The research is published today in the journal eLife.

The study’s lead author is Andrés Vidal-Gadea, a former postdoctoral researcher in the College of Natural Sciences at UT Austin, now a faculty member at Illinois State University. He noted that C. elegans is just one of myriad species living in the soil, many of which are known to migrate vertically.

“I’m fascinated by the prospect that magnetic detection could be widespread across soil dwelling organisms,” said Vidal-Gadea.

The neuroscientists and engineers, who use C. elegans in their research into Alzheimer’s disease and addiction, had previously discovered the worm’s ability to sense humidity. That work led them to ask what else the worms might be able to sense, such as magnetic fields.

In 2012, scientists from Baylor College of Medicine announced the discovery of brain cells in pigeons that process information about magnetic fields, but they did not discover which part of the body senses the fields. That team and others have proposed a magnetosensor in the birds’ inner ear.

“It’s been a competitive race to find the first magnetosensory neuron,” said Pierce-Shimomura. “And we think we’ve won with worms, which is a big surprise because no one suspected that worms could sense the Earth’s magnetic field.”

The neuron sporting a magnetic field sensor, called an AFD neuron, was already known to sense carbon dioxide levels and temperature.

The researchers discovered the worms’ magnetosensory abilities by altering the magnetic field around them with a special magnetic coil system and then observing changes in behavior. They also showed that worms which were genetically engineered to have a broken AFD neuron did not orient themselves up and down as do normal worms. Finally, the researchers used a technique called calcium imaging to demonstrate that changes in the magnetic field cause the AFD neuron to activate.

Pierce-Shimomura suggested this research might open up the possibility of manipulating magnetic fields to protect agricultural crops from harmful pests.Other members of the research team from the College of Natural Sciences are Joshua Russell, a former graduate student who completed his Ph.D.; Kristi Ward, a former undergraduate; and Celia Beron, a current undergraduate. Research team members from the Cockrell School of Engineering are: Dr. Adela Ben-Yakar, associate professor of mechanical engineering; Navid Ghorashian, a former graduate student who completed his Ph.D.; and Sertan Gokce, a current graduate student.

Support for this research came from the National Institutes of Health and the National Institute of Neurological Disorders and Stroke.

University of Texas at Austin. “First sensor of Earth’s magnetic field in an animal.” ScienceDaily. ScienceDaily, 17 June 2015. <www.sciencedaily.com/releases/2015/06/150617135040.htm>

When continents connected ?

June 14th, 2015

Riffin

A long-standing fact widely accepted among the scientific community has been recently refuted, which now has major implications on our understanding of how Earth has evolved.Until recently, most geologists had determined the land connecting North and South America, the Isthmus of Panama, had formed 3.5 million years ago.

But new data shows that this geological event, which dramatically changed the world, occurred much earlier. In a comprehensive biological study, researchers have confirmed this new information by showing that plants and animals had been migrating between the continents nearly 30 million years earlier.

“This means the best-dated geological event we ever had is wrong,” said Prosanta Chakrabarty, LSU Associate Professor in the Department of Biological Sciences and Curator of Ichthyology at the LSU Museum of Natural Science. His research on the evolution of freshwater and marine organisms in Central America was part of the study with colleagues at the Smithsonian Tropical Research Institute, American Museum of Natural History and University of Gothenburg, which included living and extinct mammals, birds, plants, fish and invertebrate animals published by the Proceedings of the National Academy of Sciences.

The researchers found large pulses of movement among these plants and animals between North and South America from 41 million, 23 million and eight million years ago. These coordinated spikes in migration imply that geological changes in Central America, such as landmass formation and new freshwater corridors, were aiding migration for many kinds of plants and animals.

“Before, South America was thought of as an island with no communication until 3.5 million years, so the only way to explain such high biodiversity was to say that it accumulated extremely fast. Now, with a longer history, we know that processes and patterns took a lot of time to form,” said Christine Bacon, lead author of the study and associate researcher at the University of Gothenburg. “Our results change our understanding of the biodiversity and climate, both at the regional and global levels.”

Even after the reported geological closure, geminate marine species, those close relatives found on opposite sides of the narrow isthmus, also provide evidence that this landmass between North and South America is more like a sponge where organisms can periodically pass rather than a solid barrier. The current expansion of the Panama Canal has yielded new fossils that have informed these observations.

One of the cichlid fish from Guatemala, Thorichthys meeki, collected by LSU Curator of Ichthyology Prosanta Chakrabarty for the study that refuted the date in which the Isthmus of Panama was formed.
Credit: Courtesy of Prosanta Chakrabarty, LSU

“Now we know that the closure of the Isthmus of Panama, which is supposed to be one of the biggest deals in geology, is just one part of a really complicated puzzle of how the continents came together,” Chakrabarty said.

He and colleagues at LSU mapped the evolution of two major families of fishes in Central America — cichlids, which include many aquarium fish, and poeciliids, which include guppies and swordtails. They collected samples of fishes from every country in Central America and sequenced the DNA to determine the genetic relationship between species. Matching the skeletal structure of fish found in the fossil record, they calibrated the DNA-based evolutionary tree and determined the age of each species.

Because freshwater fish can only migrate when a new passage way opens to a river or lake, there must have been dry land with freshwater running through it, Chakrabarty said. Therefore, their arrival in Central America signifies early geological changes.

“The cool thing is there are so many freshwater fish species that are essentially stuck in one place until the land changes, so they can tell us about the history of the Earth,” he said.

The formation of the Isthmus of Panama had large-scale effects on the planet. It divided the Atlantic and Pacific oceans, thus changing sea levels and ocean currents. This affected global temperatures possibly causing periods of glaciation.

“The geology of this whole region is so complicated, and it’s amazing to me that the biology can inform us of that,” he said. Chakrabarty has been conducting research on Central American freshwater fish for about 15 years. He has received more than $1 million in National Science Foundation funding for this work. He and his lab have collected fish species from every country in Central America and have expanded the specimen collection at LSU to South America, the Greater Antilles and much of Asia. He is currently researching the evolution and migration of freshwater fish between South America, Central America and the Greater Antilles that may have began 50 to 60 million years ago.

Video: https://www.youtube.com/watch?v=IL-9bplZa0E

Christine D. Bacon, Daniele Silvestro, Carlos Jaramillo, Brian Tilston Smith, Prosanta Chakrabarty, Alexandre Antonelli. Biological evidence supports an early and complex emergence of the Isthmus of Panama. Proceedings of the National Academy of Sciences, 2015; 112 (19): 6110

Louisiana State University. “Geological game changer: When continents connected: New study shakes up understanding of when continents connected.” ScienceDaily. ScienceDaily, 9 June 2015. <www.sciencedaily.com/releases/2015/06/150609213351.htm>.

Red Blood Cells in Fossil Fragments?

June 13th, 2015

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

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

The researchers suggest their study, published today in Nature Communications, may cause palaeontologists to rethink how fossils are preserved, and may be the first step towards a better understanding of the biology of dinosaurs and the relationships between different species.In the study, the team analysed eight fossil fragments that have for more than a century been in the Natural History Museum’s Sternberg and Cutler collections.

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

A zoom-in of potential red blood cells inside a fossil fragment that has been sliced open with a focused ion beam.
Credit: Image courtesy of Imperial College London

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

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

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

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

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

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

Journal Reference:Sergio Bertazzo, Susannah C. R. Maidment, Charalambos Kallepitis, Sarah Fearn, Molly M. Stevens and Hai-nan Xie. Fibres and cellular structures preserved in 75-million–year-old dinosaur specimens. Nature Communications, 2015 DOI: 10.1038/ncomms8352: Imperial College London. “Dinosaur fossil investigation unlocks possible soft tissue treasure trove.” ScienceDaily. ScienceDaily, 9 June 2015. <www.sciencedaily.com/releases/2015/06/150609113703.htm>.

Paleo-engineering on triceratops’ teeth revealed

June 10th, 2015

Riffin

When it comes to the three-horned dinosaur called the Triceratops, science is showing the ancient creatures might have been a little more complex than we thought.In fact, their teeth were far more intricate than any reptile or mammal living today.

Biological Science Professor Gregory Erickson and a multiuniversity team composed of engineers and paleontologists content that the Triceratops developed teeth that could finely slice through dense material giving them a richer and more varied diet than modern-day reptiles.Erickson and the team outlined the findings of their study in the journal Science Advances.

Triceratops fossil teeth

Today, reptilian teeth are constructed in such a way that they are used mostly for seizing food — whether plant or animal — and then crushing it. The teeth do not occlude — or come together — like those of mammals. In essence, they can’t chew. The teeth of most herbivorous mammals self wear with use to create complex file surfaces for mincing plants.

“It’s just been assumed that dinosaurs didn’t do things like mammals, but in some ways, they’re actually more complex,” Erickson said.

Erickson, who has been studying the evolution of dinosaurs for years, became interested in looking at dinosaurs’ teeth several years ago and suspected that they had some unique properties. But, the technology to really discover what they were capable of did not exist.

Fast-forward a few years and engineer Brandon Krick entered the picture.

Professor Gregory Erickson examines preserved teeth from a Triceratops.
Credit: Bill Lax/Florida State University

Krick is an assistant professor of mechanical engineering at Lehigh University and specializes in a relatively new area of materials science called tribology. Tribology is the science of how surfaces of materials interact while in motion.

The two of them, accompanied by scientists at University of Florida, University of Pennsylvania and the American Museum of Natural History, set out to find out what exactly these teeth were made of and how they worked.

Erickson had access to the teeth of Triceratops from museum specimens collected around North America. So, he began by cutting up a bunch of teeth to get a look at the interior.

He discovered that Triceratops teeth were made of five layers of tissue. In contrast, herbivorous horse and bison teeth, once considered the most complex ever to evolve, have four layers of tissue. Crocodiles and other reptiles have just two.

“Each of those tissues does something,” Erickson said. “They’re not just there for looks.”

While Erickson examined the tissue, he also sent samples to Krick to determine what each did and how they worked in concert to allow these animals to slice plants. Krick was able to mimic how plants moved across the teeth by scratching the teeth and measuring the tissue wear rates.

What Krick and his team of engineers, including Lehigh graduate student Mike Sidebottom, found was that the material properties of the teeth were remarkably preserved in 66 million year old teeth.

“If you took these dinosaurs’ teeth and put them in a cow for example, they would work,” Erickson said.

A sophisticated three-dimensional model was developed to show how each tissue wore with use in a strategic manner to create a complex surface with a fuller (a recessed area in the middle, much like those seen in fighting knives and swords) on each tooth. This served to reduce friction during biting and promote efficient feeding.The 3D wear model developed for this project is inspiring new engineering techniques that can be used for industrial and commercial applications.

“Paleontologists challenged us with an interesting engineering problem, and now, we have a wear model that can be used to design material systems with optimized wear properties and surface features for many applications,” Krick said.

The question that remains is how prevalent complex dental structure was among dinosaurs and other reptiles. Krick and Erickson intend to explore this further by examining other reptilian dental records and structures.This work was funded by the National Science Foundation.

Courtesy: Gregory M. Erickson, Mark A. Sidebottom, David I. Kay, Kevin T. Turner, Nathan Ip, Mark A. Norell, W. Gregory Sawyer, Brandon A. Krick. Wear biomechanics in the slicing dentition of the giant horned dinosaur Triceratops. Science Advances, 05 Jun 2015 DOI: 10.1126/sciadv.1500055 &Florida State University. “Paleo-engineering: Complexity of triceratops’ teeth revealed.” ScienceDaily. ScienceDaily, 5 June 2015. <www.sciencedaily.com/releases/2015/06/150605181935.htm>.

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