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

The unexamined diversity in the ‘Coral Triangle’

October 12th, 2014

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Research on zoantharians, a group of animals related to corals and anemones, by researchers James Reimer of the University of the Ryukyusin Okinawa, Japan, Angelo Poliseno of Universita Politecnica delle Marchein Italy, and Bert Hoeksema from Naturalis Biodiversity Center, Netherlands, has demonstrated how little we know about marine diversity in the so-called “center of marine biodiversity” located in the central Indo-Pacific Ocean.

The researchers utilized previously collected specimens from Indonesia, the Philippines, Malaysia, and Papua New Guinea, combined with field images from Dr. Hoeksema to examine species of Zoantharia, marine cnidarians commonly found in shallow subtropical and tropical oceans throughout the world. The study was published in the open access journal ZooKeys.

“The central Indo-Pacific is commonly called the “Coral Triangle” due to its high hard coral diversity, in fact the highest in the world” said Reimer, “but in fact for many groups of marine animals we really have little concrete information on diversity, or numbers of species, in this region.”

Previous research included brief reports on a few species of Zoantharia, but until now no formal attempts had been made to list species from this region. Surprisingly, of the 24 potential species identified by the researchers, at least 9 are undescribed.

Much of the work was performed by Dr. Reimer in the Netherlands in 2012, when he visited the Naturalis Museum and Dr. Hoeksema to examine their Zoantharia collection. “What struck me as particularly amazing was the fact that Naturalis housed over 600 Zoantharia specimens collected over the years, and in many cases, even specimens from 1930 had not yet been formally examined,” stated Reimer. “This research demonstrates the real importance of museum collections, as well as the lack of expert researchers for many taxonomic groups.”

“Unfortunately, for many regions of the world, we are only just beginning to examine diversity, despite some of these areas being among the most threatened,” added Reimer. It is hoped future specimen collections will allow further analyses and formal descriptions of these previously unreported species.

Physics determined ammonite shell shape

October 11th, 2014

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Ammonites are a group of extinct cephalopod mollusks with ribbed spiral shells. They are exceptionally diverse and well known to fossil lovers. Régis Chirat, researcher at the Laboratoire de Géologie de Lyon: Terre, Planètes et Environnement (CNRS/Université Claude Bernard Lyon 1/ENS de Lyon), and two colleagues from the Mathematical Institute at the University of Oxford have developed the first biomechanical model explaining how these shells form and why they are so diverse. Their approach provides new paths for interpreting the evolution of ammonites and nautili, their smooth-shelled distant “cousins” that still populate the Indian and Pacific oceans. This work has just been published on the website of the Journal of Theoretical Biology.

The mechanical model predicts the correlations observed between rib frequency and amplitude and the shell’s general shape in ammonites (blue morphological space) and nautili (red morphological space) The 3D-views produced by the model are juxtaposed with fossil specimens, ammonites and nautili, that have a similar shape. The ribs tend to disappear for the broadly open shell shapes that have characterized nautili for almost 200 million years. W = expansion rate D = coiling tightness
Credit: Copyright: © Derek Moulton, Alain Goriely and Régis Chirat

The shape of living organisms evolves over time. The questions raised by this transformation have led to the emergence of theories of evolution. To understand how biological shapes change over a geological time scale, researchers have recently begun to investigate how they are generated during an individual’s development and growth: this is known as morphogenesis. Due to the exceptional diversity of their shell shapes and patterns (particularly the ribs), ammonites have been widely studied from the point of view of evolution but the mechanisms underlying the coiled spirals were unknown until now. Researchers therefore attempted to elucidate the evolution of these shapes without knowing how they had emerged.

Régis Chirat and his team have developed a model that explains the morphogenesis of these shells. By using mathematical equations to describe how the shell is secreted by ammonite and grows, they have demonstrated the existence of mechanical forces specific to developing mollusks. These forces depend on the physical properties of the biological tissues and on the geometry of the shell. They cause mechanical oscillations at the edge of the shell that generate ribs, a sort of ornamental pattern on the spiral.

By examining various fossil specimens in light of the simulations produced by the model, the researchers observed that the latter can predict the number and shape of ribs in several ammonites. The model shows that the ornamentation of the shell evolves as a function of variables such as tissue elasticity and shell expansion rate (the rate at which the diameter of the opening increases with each spiral coil).

By providing a biophysical explanation for how these ornamentations form, this theoretical approach explains the diversity existing within and between species. It thus opens new perspectives for the study of the morphological evolution of ammonites, which seems to be largely governed by mechanical and geometric constraints. This new tool also sheds light on an old mystery. For almost 200 million years, the shells of nautili, distant “cousins” of ammonites, have remained essentially smooth and free of distinctive ornamentation. The model shows that having maintained this shell shape does not mean that nautili — wrongly referred to as “living fossils” — have not evolved, but is due to a high expansion rate, leading to the formation of smooth shells that are difficult to distinguish from one another.

More generally, this work highlights the value of studying the physical bases of biological development: understanding the “construction rules” underlying the morphological diversity of organisms makes it possible to partially predict how their shape evolves.

How dinosaur arms turned into bird wings

October 7th, 2014

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Although we now appreciate that birds evolved from a branch of the dinosaur family tree, a crucial adaptation for flight has continued to puzzle evolutionary biologists. During the millions of years that elapsed, wrists went from straight to bent and hyperflexible, allowing birds to fold their wings neatly against their bodies when not flying.

How this happened has been the subject of much debate, with substantial disagreement between developmental biologists, who study how the wings of modern birds develop in the growing embryo, and palaeontologists who study the bones of dinosaurs and early birds. A resolution to this impasse is now provided by an exciting new study publishing on September 30 in PLOS Biology.

(A) Whole-mount alcian blue staining confirms the ulnare is the first carpal formed in avian embryos, distal to the ulna. Thereafter, a distal carpal 3 (referred to as “element x” in previous embryological descriptions) is formed distal to the ulnare, coexisting with it. Finally, the ulnare disappears, whereas dc3 persists.
Credit: J. Botelho et al.; DOI: 10.1371/journal.pbio.1001957

Underlying this striking evolutionary transformation change is a halving in the number of wrist bones, but developmental biologists and palaeontologists have different names for most of them, and seldom agree on the correspondence between specific dinosaur bones and those of their bird descendants. Indeed, each field has radically different data sources, methods, and research objectives, talking little to each other.

The critical advance made in the new study involved combining these two strands of research. Using an interdisciplinary approach, the lab run by Alexander Vargas at the University of Chile has re-examined fossils stored at several museum collections, while at the same time collecting new developmental data from seven different species of modern birds. Joao Botelho, a Brazilian student in Vargas’ lab, developed a revolutionary new technique that allows him to study specific proteins in 3D embryonic skeletons. By combining these data from both fossils and embryos, the research team has made a major step forward in clarifying how the bird wrist evolved.

From early dinosaur ancestors with as many as nine wrist bones, birds have only kept four during the course of evolution, but which of the original bones are they? The identity of each of these bones was debated. For instance, the late Yale professor John Ostrom famously pointed out in the 1970’s that the wrists of both birds and bird-like dinosaurs possess a very similar, half-moon shaped bone called the semilunate, and that this bone resulted from the merging of two bones present in dinosaurs. This formed part of Ostrom’s then-controversial argument that birds descended from dinosaurs. However, the failure of developmental biologists to confirm this raised doubts that it was the same bone, and even that birds came from dinosaurs.

Now, the new data obtained by the Vargas lab has revealed the first developmental evidence that the bird semilunate was formed by the fusion of the two dinosaur bones. They go on to show that another bone — the pisiform — was lost in bird-like dinosaurs, but then re-acquired in the early evolution of birds, probably as an adaptation for flight, where it allows transmission of force on the downstroke while restricting flexibility on the upstroke. Combined, the fossil and developmental data provide a compelling scenario for a rare case of evolutionary reversal.

The study by the Vargas lab also settled the identity of the other two bones of the bird wrist, which were commonly misidentified in both fields. This emphasizes the downsides of not integrating all data sources, and reveals a situation perhaps akin to that of astronomy and experimental physics in the pursuit of cosmology: Together, palaeontology and development can come much closer to telling the whole story of evolution — this integrative approach resolves previous disparities that have challenged the support for the dinosaur-bird link and reveals previously undetected processes, including loss of bones, fusion of bones, and re-evolution of a transiently lost bone.

Fossil of ancient multicellular life sets evolutionary timeline back 60 million years

October 4th, 2014

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A Virginia Tech geobiologist with collaborators from the Chinese Academy of Sciences have found evidence in the fossil record that complex multicellularity appeared in living things about 600 million years ago — nearly 60 million years before skeletal animals appeared during a huge growth spurt of new life on Earth known as the Cambrian Explosion.

A fossil of a 600 million-year-old multicellular organism displays unexpected evidence of complexity.
Credit: Virginia Tech

The discovery published online Wednesday in the journal Nature contradicts several longstanding interpretations of multicellular fossils from at least 600 million years ago.

“This opens up a new door for us to shine some light on the timing and evolutionary steps that were taken by multicellular organisms that would eventually go on to dominate the Earth in a very visible way,” said Shuhai Xiao, a professor of geobiology in the Virginia Tech College of Science. “Fossils similar to these have been interpreted as bacteria, single-cell eukaryotes, algae, and transitional forms related to modern animals such as sponges, sea anemones, or bilaterally symmetrical animals. This paper lets us put aside some of those interpretations.”

In an effort to determine how, why, and when multicellularity arose from single-celled ancestors, Xiao and his collaborators looked at phosphorite rocks from the Doushantuo Formation in central Guizhou Province of South China, recovering three-dimensionally preserved multicellular fossils that showed signs of cell-to-cell adhesion, differentiation, and programmed cell death — qualities of complex multicellular eukaryotes such as animals and plants.

The discovery sheds light on how and when solo cells began to cooperate with other cells to make a single, cohesive life form.

The complex multicellularity evident in the fossils is inconsistent with the simpler forms such as bacteria and single-celled life typically expected 600 million years ago.

While some hypotheses can now be discarded, several interpretations may still exist, including the multicellular fossils being transitional forms related to animals or multicellular algae.

Xiao said future research will focus on a broader paleontological search to reconstruct the complete life cycle of the fossils.

Xiao earned his bachelor’s and master’s degrees from Beijing University in 1988 and 1991 and his doctoral degree from Harvard University in 1998. He worked for three years at Tulane University before arriving at Virginia Tech in 2003.

He is currently active in an editorial role for seven professional publications and has published more than 130 papers.

52-million-year-old amber preserves ‘ant-loving’ beetle

October 3rd, 2014

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Scientists have uncovered the fossil of a 52-million-year old beetle that likely was able to live alongside ants — preying on their eggs and usurping resources — within the comfort of their nest. The fossil, encased in a piece of amber from India, is the oldest-known example of this kind of social parasitism, known as “myrmecophily.” Published today in the journal Current Biology, the research also shows that the diversification of these stealth beetles, which infiltrate ant nests around the world today, correlates with the ecological rise of modern ants.

Scientists have uncovered the fossil of a 52-million-year old beetle that likely was able to live alongside ants—preying on their eggs and usurping resources—within the comfort of their nest.
Credit: © AMNH/J. Parker

“Although ants are an integral part of most terrestrial ecosystems today, at the time that this beetle was walking the Earth, ants were just beginning to take off, and these beetles were right there inside the ant colonies, deceiving them and exploiting them,” said lead author Joseph Parker, a research associate at the American Museum of Natural History and postdoctoral researcher at Columbia University, who is a specialist on these beetles. “This tells us something not just about the beetles, but also about the ants — their nests were big enough and resource-rich enough to be worthy of exploitation by these super-specialized insects. And when ants exploded ecologically and began to dominate, these beetles exploded with them.”

Today, there are about 370 described species belonging to Clavigeritae, a group of myrmecophilous, or “ant-loving” beetles about 1-3 millimeters in length, and Parker estimates that several times this number of species still await discovery. Remarkable adaptations enable these beetles to bypass the fortresslike security of ant nests, which employ a pheromone code of recognition that ants use to identify, and then dismember and consume, intruders. Through ways that scientists are still trying to understand, Clavigeritae beetles pass through these defenses and integrate seamlessly into colony life.

“Adopting this lifestyle brings lots of benefits. These beetles live in a climate- controlled nest that is well protected against predators, and they have access to a great deal of food, including the ants’ eggs and brood, and, most remarkably, liquid food regurgitated directly to their mouths by the worker ants themselves,” Parker said. “But pulling off this way of life means undergoing drastic morphological changes.”

Clavigeritae beetles look quite different from their closest relatives, with fusions of segments within the abdomen and antennae — likely meant to provide additional protection from the ants, which often pick the beetles up and carry them around the nest — and mouthparts that are recessed inside the head in order to accept liquid food from worker ants. They also have glands that cover the body with oily secretions, and thick brushes of hair on top of their abdomens, called trichomes, which act as candlewicks and conduct chemical-containing secretions from nearby glands. The makeup of these chemicals is unknown, but they are thought to encourage ants to “adopt” rather than attack the beetles.

“If you watch one of these beetles interact inside an ant colony, you’ll see the ants running up to it and licking those brush-like structures,” Parker said.

Although Clavigeritae beetles are species-rich, they are quite rarely encountered in nature and so, unsurprisingly, the newly discovered specimen — brought to Parker’s attention by American Museum of Natural History curator David Grimaldi, who is an expert in amber fossils — is thought to be the first fossil of this group to be discovered. Named Protoclaviger trichodens by Parker and Grimaldi, the Eocene fossil is from an amber deposit in what was once a rain-forest environment in modern-day India. Although its body is very similar to modern Clavigeritae beetles, with two stark, hook-like trichomes, some of its characteristics are clearly more primitive. For example, Protoclaviger’s abdominal segments are still distinct, whereas in modern beetles they are fused together into a single shieldlike segment.

“Protoclaviger is a truly transitional fossil,” Parker said. “It marks a big step along the pathway that led to the highly modified social parasites we see today, and it helps us figure out the sequence of events that led to this sophisticated morphology.”

Prehistoric predators tangled across land, sea

September 30th, 2014

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About 210 million years ago when the supercontinent of Pangea was starting to break up and dog-sized dinosaurs were hiding from nearly everything, entirely different kinds of reptiles called phytosaurs and rauisuchids were at the top of the food chain.

It was widely believed the two top predators didn’t interact much as the former was king of the water, and the latter ruled the land. But those ideas are changing, thanks largely to the contents of a single bone.

Teeth from phytosaurs, a reptile from the Triassic Period about 210 million years ago in what is now the western United States. The blue tooth on the left is a 3-D printed replica of a tooth embedded in the thigh bone of a rauisuchid, another Triassic period carnivore. The details of the tooth were digitally extracted using CT scans.
Credit: Virginia Tech

In a paper published online in September in the German journal Naturwissenschaften, Stephanie Drumheller of the University of Tennessee and Michelle Stocker and Sterling Nesbitt, vertebrate paleontologists with the Virginia Tech’s Department of Geosciences, present evidence the two creatures not only interacted, but did so on purpose.

“Phytosaurs were thought to be dominant aquatic predators because of their large size and similarity to modern crocodylians,” said Stocker, “but we were able to provide the first direct evidence they targeted both aquatic and large terrestrial prey.”

The evidence? A tooth. Not just any tooth, but the tooth of a phytosaur lodged in the thigh bone of a rauisuchid, a creature about 25 feet long and 4 feet high at the hip. The tooth lay broken off and buried about two inches deep in bone, and then healed over, indicating the rauisuchid survived the attack.

“Finding teeth embedded directly in fossil bone is very, very rare,” Drumheller said. “This is the first time it’s been identified among phytosaurs, and it gives us a smoking gun for interpreting this set of bite marks.”

The researchers came across the bone by chance at the University of California Museum of Paleontology in Berkeley.

“It was remarkable we were able to reconstruct a part of an ancient food web from over 210 million years ago from a few shallow marks and a tooth in a bone,” said Nesbitt. “It goes to show how careful observation can lead to important discoveries even when you’re not seeking those answers.

“We came across this bone and realized pretty quickly we had something special,” Nesbitt said. “There are many bones that get dug up, not all are immediately processed, prepared, and studied. No one had recognized the importance of this specimen before but we were able to borrow it and make our study.”

The large rauisuchid thigh bone at the center of the research has the tooth of the attacker, which the researchers recreated using CT scans and a 3-D printer. Multiple bite marks indicate the creature was preyed upon at least twice over the course of its life, by phytosaurs.

“This research will call for us to go back and look at some of the assumptions we’ve had in regard to the Late Triassic ecosystems,” Stocker said. “The distinctions between aquatic and terrestrial distinctions were over-simplified and I think we’ve made a case that the two spheres were intimately connected.”

Drilling Into an Active Earthquake Fault

September 28th, 2014

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Three University of Michigan geologists are participating in an international effort to drill nearly a mile beneath the surface of New Zealand this fall to bring back rock samples from an active fault known to generate major earthquakes.

The goal of the Deep Fault Drilling Project is to better understand earthquake processes by sampling the Alpine Fault, which is expected to trigger a large event in the coming decades.

“We’re trying to understand why some faults are more earthquake-prone than others, and that requires fundamental knowledge about the processes at work,” said Ben van der Pluijm, the Bruce R. Clark Collegiate Professor of Geology in the U-M Department of Earth and Environmental Sciences.

An aerial view of the Alpine Fault at Gaunt Creek, where the Deep Fault Drilling Project is scheduled to begin next month. Three University of Michigan geologists are participating in the $2.5 million international project, which will drill nearly a mile beneath the surface and return rock samples from an active fault known to generate major earthquakes.
Credit: Photo by Ben van der Pluijm

Van der Pluijm and two of his EES colleagues — doctoral student Austin Boles and research scientist Anja Schleicher — are part of the team scheduled to start the two-month drilling project early next month. Schleicher will spend October at the site, and Boles will be there for about six weeks starting in early November.

It will be only the second science project to drill deep into an active earthquake fault and return samples. Several years ago, scientists drilled a nearly 2-mile-deep hole into California’s San Andreas Fault. Van der Pluijm was a member of that team, as well.

“I hope we find something different this time, a different rock signature that contrasts with what we saw at the San Andreas,” he said.

The goal is to drill 0.8 miles (1.3 kilometers) into the 530-mile-long Alpine Fault, which marks the boundary between the Australian and Pacific tectonic plates, on New Zealand’s South Island. Though most of the movement along the fault is lateral rather than vertical, the fault is responsible for lifting the Southern Alps, the rugged mountain range featured in the “Lord of the Rings” movies.

Earthquakes occur on the Alpine Fault every 200 to 400 years at magnitudes of 7.5 to 8.0, with an average time between successive large earthquakes of about 330 years. Though earthquakes of that size that originate at shallow depths are capable of tremendous damage, the region is sparsely populated.

The last Alpine Fault quake occurred in 1717, and the probability of another big one occurring there in the next 50 years has been calculated at about 28 percent. So the $2.5 million Deep Fault Drilling Project presents a rare opportunity to collect and analyze samples from a major fault before it breaks.

The task for van der Pluijm and his colleagues is to analyze the possible role of clay minerals and friction melting in the fault zone. Radiometric dating, X-ray studies and isotopic-analysis techniques will be used to determine how much clay is in the rock samples and when those clays formed, as well as the likely source of the water that helped produce them.

“The information we can extract from these clays is remarkably rich,” said Boles, who will use data from the New Zealand study in his doctoral dissertation. “These clay minerals are a key tool that we can use to better understand the physical and chemical processes happening in an active fault.”

Clay minerals can help reduce friction and heat generation along a fault, lubricating it so that pressure is released through steady, relatively small and nondestructive “creeping” motions rather than the periodic violent jolts known as earthquakes.

Creeping motions were observed along the portion of the San Andreas Fault drilled by scientists several years ago. Temperatures in that fault were relatively low, and clay-rich rocks from the active zone were returned to the surface.

“We think that clays are a significant player in making faults less earthquake-prone,” van der Pluijm said. “We know that the section of the Alpine Fault we’ll be drilling has a history of producing large earthquakes. So finding little clay and, instead, evidence for frictional melting in the rock would better fit the large-earthquake scenario. That would be a fantastic breakthrough.”

In addition to sampling the fault during the two-month drilling program, researchers will install permanent pressure, temperature and seismic-monitoring sensors in the borehole.

The U-M researchers are hoping to obtain a rock sample about the volume of a baseball from deep within the Alpine Fault. That would be plenty to complete their various studies, which are funded by the National Science Foundation and the International Continental Scientific Drilling Program.

“Getting the right samples is more important than the amount,” van der Pluijm said. “Returning samples to the surface from depth is always a challenge, but I’m confident that it will work.”

Dinosaur family tree gives clues on the evolution of birds

September 27th, 2014

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The most comprehensive family tree of meat-eating dinosaurs ever created is enabling scientists to discover key details of how birds evolved from them.

The study, published in the journal Current Biology, shows that the familiar anatomical features of birds — such as feathers, wings and wishbones — all first evolved piecemeal in their dinosaur ancestors over tens of millions of years.

Researchers examined the evolutionary links between ancient birds and their closest dinosaur relatives, by analyzing the anatomical make-up of more than 850 body features in 150 extinct species, and used statistical techniques to analyze their findings and assemble a detailed family tree.
Credit: Steve Brusatte

However, once a fully functioning bird body shape was complete, an evolutionary explosion began, causing a rapid increase in the rate at which birds evolved. This led eventually to the thousands of avian species that we know today.

A team of researchers, led by the University of Edinburgh (UK) and including Swarthmore College Associate Professor of Statistics Steve C. Wang, examined the evolutionary links between ancient birds and their closest dinosaur relatives. They did this by analyzing the anatomical make-up of more than 850 body features in 150 extinct species and used statistical techniques to analyze their findings and assemble a detailed family tree.

Based on their findings from fossil records, researchers say the emergence of birds some 150 million years ago was a gradual process, as some dinosaurs became more bird-like over time. This makes it very difficult to draw a dividing line on the family tree between dinosaurs and birds.

Findings from the study support a controversial theory proposed in the 1940s that the emergence of new body shapes in groups of species could result in a surge in their evolution.

“The evolution of birds from their dinosaur ancestors was a landmark in the history of life,” says Wang. “This process was so gradual that if you traveled back in time to the Jurassic, you’d find that the earliest birds looked indistinguishable from many other dinosaurs.”

Wang invented a novel statistical method that was able to take advantage of new kinds of data from the fossil record, which reached the conclusion that early birds had a high rate of evolution. He adds that “birds as we know them evolved over millions of years, accumulating small shifts in shape and function of the skeleton. But once all these pieces were in place to form the archetypal bird skeleton, birds then evolved rapidly, eventually leading to the great diversity of species we know today.”

“There was no moment in time when a dinosaur became a bird, and there is no single missing link between them, ” says Steve Brusatte of the University of Edinburgh’s School of GeoSciences, who led the study. “What we think of as the classic bird skeleton was pieced together gradually over tens of millions of years. Once it came together fully, it unlocked great evolutionary potential that allowed birds to evolve at a super-charged rate.”

The work was supported by the European Commission, National Science Foundation, the University of Edinburgh, Swarthmore College’s Research Fund, Swarthmore College’s James Michener Faculty Fellowship, Columbia University, and the American Museum of Natural History.

New explanation for origin of plate tectonics?

September 23rd, 2014

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The mystery of what kick-started the motion of our earth’s massive tectonic plates across its surface has been explained by researchers at the University of Sydney.

“Earth is the only planet in our solar system where the process of plate tectonics occurs,” said Professor Patrice Rey, from the University of Sydney’s School of Geosciences.

“The geological record suggests that until three billion years ago the Earth’s crust was immobile so what sparked this unique phenomenon has fascinated geoscientists for decades. We suggest it was triggered by the spreading of early continents then eventually became a self-sustaining process.”

Professor Rey is lead author of an article on the findings published in Nature on Wednesday, 17 September.

The other authors on the paper are Nicolas Flament, also from the School of Geosciences and Nicolas Coltice, from the University of Lyon.

There are eight major tectonic plates that move above Earth’s mantle at rates up to 150 millimetres every year.

The image shows a snapshot from the film after 45 million years of spreading. The pink is the region where the mantle underneath the early continent has melted, facilitating its spreading, and the initiation of the plate tectonic process.
Credit: Patrice Rey, Nicolas Flament and Nicolas Coltice

In simple terms the process involves plates being dragged into the mantle at certain points and moving away from each other at others, in what has been dubbed ‘the conveyor belt’.

Plate tectonics depends on the inverse relationship between density of rocks and temperature.

At mid-oceanic ridges, rocks are hot and their density is low, making them buoyant or more able to float. As they move away from those ridges they cool down and their density increases until, where they become denser than the underlying hot mantle, they sink and are ‘dragged’ under.

But three to four billion years ago, Earth’s interior was hotter, volcanic activity was more prominent and tectonic plates did not become cold and dense enough to spontaneously sank.

“So the driving engine for plate tectonics didn’t exist,” said Professor Rey said.

“Instead, thick and buoyant early continents erupted in the middle of immobile plates. Our modelling shows that these early continents could have placed major stress on the surrounding plates. Because they were buoyant they spread horizontally, forcing adjacent plates to be pushed under at their edges.”

“This spreading of the early continents could have produced intermittent episodes of plate tectonics until, as the Earth’s interior cooled and its crust and plate mantle became heavier, plate tectonics became a self-sustaining process which has never ceased and has shaped the face of our modern planet.”

The new model also makes a number of predictions explaining features that have long puzzled the geoscience community.

Rhinorex condrupus :Hadrosaur with huge nose discovered

September 19th, 2014

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Call it the Jimmy Durante of dinosaurs — a newly discovered hadrosaur with a truly distinctive nasal profile. The new dinosaur, named Rhinorex condrupus by paleontologists from North Carolina State University and Brigham Young University, lived in what is now Utah approximately 75 million years ago during the Late Cretaceous period.

Rhinorex, which translates roughly into “King Nose,” was a plant-eater and a close relative of other Cretaceous hadrosaurs like Parasaurolophus and Edmontosaurus. Hadrosaurs are usually identified by bony crests that extended from the skull, although Edmontosaurus doesn’t have such a hard crest (paleontologists have discovered that it had a fleshy crest). Rhinorex also lacks a crest on the top of its head; instead, this new dinosaur has a huge nose.

Terry Gates, a joint postdoctoral researcher with NC State and the North Carolina Museum of Natural Sciences, and colleague Rodney Sheetz from the Brigham Young Museum of Paleontology, came across the fossil in storage at BYU. First excavated in the 1990s from Utah’s Neslen formation, Rhinorex had been studied primarily for its well-preserved skin impressions. When Gates and Sheetz reconstructed the skull, they realized that they had a new species.

“We had almost the entire skull, which was wonderful,” Gates says, “but the preparation was very difficult. It took two years to dig the fossil out of the sandstone it was embedded in — it was like digging a dinosaur skull out of a concrete driveway.”

The newly discovered hadrosaur, Rhinorex condrupus, has a truly distinctive nasal profile.
Credit: Terry Gates

Based on the recovered bones, Gates estimates that Rhinorex was about 30 feet long and weighed over 8,500 lbs. It lived in a swampy estuarial environment, about 50 miles from the coast. Rhinorex is the only complete hadrosaur fossil from the Neslen site, and it helps fill in some gaps about habitat segregation during the Late Cretaceous.

“We’ve found other hadrosaurs from the same time period but located about 200 miles farther south that are adapted to a different environment,” Gates says. “This discovery gives us a geographic snapshot of the Cretaceous, and helps us place contemporary species in their correct time and place. Rhinorex also helps us further fill in the hadrosaur family tree.”

When asked how Rhinorex may have benefitted from a large nose Gates said, “The purpose of such a big nose is still a mystery. If this dinosaur is anything like its relatives then it likely did not have a super sense of smell; but maybe the nose was used as a means of attracting mates, recognizing members of its species, or even as a large attachment for a plant-smashing beak. We are already sniffing out answers to these questions.”