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

Mass Extinction Study Provides Lessons for Modern World

November 5th, 2012

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The Cretaceous Period of Earth history ended with a mass extinction that wiped out numerous species, most famously the dinosaurs. A new study now finds that the structure of North American ecosystems made the extinction worse than it might have been. Researchers at the University of Chicago, the California Academy of Sciences and the Field Museum of Natural History will publish their findings Oct. 29 online in theProceedings of the National Academy of Sciences.

The mountain-sized asteroid that left the now-buried Chicxulub impact crater on the coast of Mexico’s Yucatan Peninsula is almost certainly the ultimate cause of the end-Cretaceous mass extinction, which occurred 65 million years ago. Nevertheless, “Our study suggests that the severity of the mass extinction in North America was greater because of the ecological structure of communities at the time,” noted lead author Jonathan Mitchell, a Ph.D. student of UChicago’s Committee on Evolutionary Biology.

This illustration depicts the food web for ecological groups in the late Cretaceous Period as reported in a new paper published in the Proceedings of the National Academy of Sciences. Each ecological group includes a set of species that share the same set of potential predators and prey. Silhouettes show iconic members of each group. Arrows show who eats whom. (Credit: Courtesy of Jonathan Mitchell, Peter Roopnarine and Kenneth Angielczyk

Mitchell and his co-authors, Peter Roopnarine of the California Academy of Sciences and Kenneth Angielczyk of the Field Museum, reconstructed terrestrial food webs for 17 Cretaceous ecological communities. Seven of these food webs existed within two million years of the Chicxulub impact and 10 came from the preceding 13 million years.

The findings are based on a computer model showing how disturbances spread through the food web. Roopnarine developed the simulation to predict how many animal species would become extinct from a plant die-off, a likely consequence of the impact.

“Our analyses show that more species became extinct for a given plant die-off in the youngest communities,” Mitchell said. “We can trace this difference in response to changes in a number of key ecological groups such as plant-eating dinosaurs like Triceratops and small mammals.”

The results of Mitchell and his colleagues paint a picture of late Cretaceous North America in which pre-extinction changes to food webs — likely driven by a combination of environmental and biological factors — results in communities that were more fragile when faced with large disturbances.

“Besides shedding light on this ancient extinction, our findings imply that seemingly innocuous changes to ecosystems caused by humans might reduce the ecosystems’ abilities to withstand unexpected disturbances,” Roopnarine said.

The team’s computer model describes all plausible diets for the animals under study. In one run, Tyrannosaurus might eat only Triceratops, while in another it eats only duck-billed dinosaurs, and in a third it might eat a more varied diet. This stems from the uncertainty regarding exactly what Cretaceous animals ate, but this uncertainty actually worked to the study’s benefit.

“Using modern food webs as guides, what we have discovered is that this uncertainty is far less important to understanding ecosystem functioning than is our general knowledge of the diets and the number of different species that would have had a particular diet,” Angielczyk said.

Data derived from modern food webs helped the simulations account for such phenomena as how specialized animals tend to be, or how body size relates to population size and thus their probability of extinction.

The researchers also selected for their study a large number of specific food webs from all the specific webs possible in their general framework and evaluated how this sample of webs respond to a perturbation, such as the death of plants. They used the same relationships and assumptions to create food webs across all of the different sites, which means the differences between sites just stem from differences in the data rather than from the simulation itself. This makes the simulation a fundamentally comparative method, Roopnarine noted.

“We aren’t trying to say that a given ecosystem was fragile, but instead that a given ecosystem was more or less fragile than another,” he said.

The computer models showed that if the asteroid hit during the 13 million years preceding the latest Cretaceous communities, there almost certainly would still have been a mass extinction, but one that likely would have been less severe in North America.

Most likely a combination of changing climate and other environmental factors caused some types of animals to become more or less diverse in the Cretaceous, the researchers concluded. In their paper they suggest that the drying up of a shallow sea that covered part of North America may have been one of the main factors leading to the observed changes in diversity.

The study provides no evidence that the latest Cretaceous communities were on the verge of collapse before the asteroid hit. “The ecosystems collapsed because of the asteroid impact, and nothing in our study suggests that they would not have otherwise continued on successfully,” Mitchell said. “Unusual circumstances, such as the after-effects of the asteroid impact, were needed for the vulnerability of the communities to become important.”

The study has implications for modern conservation efforts, Angielczyk observed.

“Our study shows that the robustness or fragility of an ecosystem under duress depends very much on both the number of species present, as well as the types of species,” he said, referring to their ecological function. The study also shows that more is not necessarily better, because simply having many species does not insure against ecosystem collapse.

“What you have is also important,” Angelczyk said. “It is therefore critical that conservation efforts pay attention to ecosystem functioning and the roles of species in their communities as we continue to degrade our modern ecosystems.”

MOUNT ST HELENS

November 4th, 2012

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MOUNT ST HELENS

Mount St Helens is located in the Cascade mountain range in the state of Washington in the United States and is famous for its devastating 1980 eruption, which killed 57 people. Among the dead were a geologist and others who were monitoring thevolcano. The victims closest to the eruption were killed almost instantly when an earthquake triggered a huge landslide that unleashed a sideways blast that sent clouds of hot gas, ash and rock speeding away from the volcano.

The eruption of Mount St Helens and another volcano in Mexico called El Chichon two years later were the first times that pyroclastic flows – clouds of very hot gas, ash and rock that move at hundreds of miles per hour – were studied using modern scientific techniques.

Mount St Helens remains active and has erupted periodically since 1980.

Image: Mount St Helens erupts in July 1980 (credit: Science Source/USGS/Science Photo Library)

Were Dinosaurs Destined to Be Big? Testing Cope’s Rule

November 3rd, 2012

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In the evolutionary long run, small critters tend to evolve into bigger beasts — at least according to the idea attributed to paleontologist Edward Cope, now known as Cope’s Rule. Using the latest advanced statistical modeling methods, a new test of this rule as it applies dinosaurs shows that Cope was right — sometimes.

In the evolutionary long run, small critters tend to evolve into bigger beasts — at least according to the idea attributed to paleontologist Edward Cope, now known as Cope’s Rule. Using the latest advanced statistical modeling methods, a new test of this rule as it applies dinosaurs shows that Cope was right — sometimes. (Credit: © Derrick Neill / Fotolia)

“For a long time, dinosaurs were thought to be the example of Cope’s Rule,” says Gene Hunt, curator in the Department of Paleobiology at the National Museum of Natural History (NMNH) in Washington, D.C. Other groups, particularly mammals, also provide plenty of classic examples of the rule, Hunt says.

To see if Cope’s rule really applies to dinosaurs, Hunt and colleagues Richard FitzJohn of the University of British Columbia and Matthew Carrano of the NMNH used dinosaur thigh bones (aka femurs) as proxies for animal size. They then used that femur data in their statistical model to look for two things: directional trends in size over time and whether there were any detectable upper limits for body size.

“What we did then was explore how constant a rule is this Cope’s Rule trend within dinosaurs,” said Hunt. They looked across the “family tree” of dinosaurs and found that some groups, or clades, of dinosaurs do indeed trend larger over time, following Cope’s Rule. Ceratopsids and hadrosaurs, for instance, show more increases in size than decreases over time, according to Hunt. Although birds evolved from theropod dinosaurs, the team excluded them from the study because of the evolutionary pressure birds faced to lighten up and get smaller so they could fly better.

As for the upper limits to size, the results were sometimes yes, sometimes no. The four-legged sauropods (i.e., long-necked, small-headed herbivores) and ornithopod (i.e., iguanodons, ceratopsids) clades showed no indication of upper limits to how large they could evolve. And indeed, these groups contain the largest land animals that ever lived.

Theropods, which include the famous Tyrannosaurus rex, on the other hand, did show what appears to be an upper limit on body size. This may not be particularly surprising, says Hunt, because theropods were bipedal, and there are physical limits to how massive you can get while still being able to move around on two legs.

Hunt, FitzJohn, and Carrano will be presenting the results of their study on Nov. 4, at the annual meeting of The Geological Society of America in Charlotte, North Carolina, USA.

As for why Cope’s Rule works at all, that is not very well understood, says Hunt. “It does happen sometimes, but not always,” he added. The traditional idea that somehow “bigger is better” because a bigger animal is less likely to be preyed upon is naïve, Hunt says. After all, even the biggest animals start out small enough to be preyed upon and spend a long, vulnerable, time getting gigantic.

Exhaustive Family Tree for Birds Shows Recent, Rapid Diversification

November 1st, 2012

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A Yale-led scientific team has produced the most comprehensive family tree for birds to date, connecting all living bird species — nearly 10,000 in total — and revealing surprising new details about their evolutionary history and its geographic context.

Analysis of the family tree shows when and where birds diversified — and that birds’ diversification rate has increased over the last 50 million years, challenging the conventional wisdom of biodiversity experts.

Analysis of the family tree shows when and where birds diversified — and that birds’ diversification rate has increased over the last 50 million years, challenging the conventional wisdom of biodiversity experts. (Credit: Image courtesy of Yale University)

“It’s the first time that we have — for such a large group of species and with such a high degree of confidence — the full global picture of diversification in time and space,” said biologist Walter Jetz of Yale, lead author of the team’s research paper, published Oct. 31 online in the journal Nature.

He continued: “The research highlights how heterogeneously fast diversifying species groups are distributed throughout the family tree and over geographic space. Many parts of the globe have seen a variety of species groups diversify rapidly and recently. All this leads to a diversification rate in birds that has been increasing over the past 50 million years.”

The researchers relied heavily on fossil and DNA data, combining them with geographical information to produce the exhaustive family tree, which includes 9,993 species known to be alive now.

“The current zeitgeist in biodiversity science is that the world can fill up quickly,” says biologist and co-author Arne Mooers of Simon Fraser University in Canada. “A new distinctive group, like bumblebees or tunafish, first evolves, and, if conditions are right, it quickly radiates to produce a large number of species. These species fill up all the available niches, and then there is nowhere to go. Extinction catches up, and things begin to slow down or stall. For birds the pattern is the opposite: Speciation is actually speeding up, not slowing down.”

The researchers attribute the growing rate of avian diversity to an abundance of group-specific adaptations. They hypothesize that the evolution of physical or behavioral innovations in certain groups, combined with the opening of new habitats, has enabled repeated bursts of diversification. Another likely factor has been birds’ exceptional mobility, researchers said, which time and again has allowed them to colonize new regions and exploit novel ecological opportunities.

In their analysis, the researchers also expose significant geographic differences in diversification rates. They are higher in the Western Hemisphere than in the Eastern, and higher on islands than mainlands. But surprisingly, they said, there is little difference in rates between the tropics and high latitudes. Regions of especially intense recent diversification include northern North American and Eurasia and southern South America.

“This was one of the big surprises,” Jetz said. “For a long time biologists have thought that the vast diversity of tropical species must at least partly be due to greater rates of net species production there. For birds we find no support for this, and groups with fast and slow diversification appear to occur there as much as in the high latitudes. Instead, the answer may lie in the tropics’ older age, leading to a greater accumulation of species over time. Global phylogenies like ours will allow further tests of this and other basic hypotheses about life on Earth.”

Other authors are G.H. Thomas of the University of Bristol in the United Kingdom; J.B. Joy of Simon Fraser University in Canada; and K. Hartmann of the University of Tasmania in Australia.

The work was supported by the National Science Foundation, NASA, the Natural Environment Research Council (U.K), the Natural Sciences and Engineering Research Council of Canada, Simon Fraser University, and the Yale Institute of Biospheric Studies.

CT scans reveal that dinosaurs were airheads

October 31st, 2012

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Paleontologists have long known that dinosaurs had tiny brains, but they had no idea the beasts were such airheads.

A new study by Ohio University researchers Lawrence Witmer and Ryan Ridgely found that dinosaurs had more air cavities in their heads than expected. By using CT scans, the scientists were able to develop 3-D images of the dinosaur skulls that show a clearer picture of the physiology of the airways.

Compared to brainy humans, dinosaurs were airheads. The head of Tyrannosaurus rex was filled with sinuses that lightened the head while enhancing its strength. – Lawrence Witmer/Ryan Ridgely, Ohio University

“I’ve been looking at sinuses for a long time, and indeed people would kid me about studying nothing-looking at the empty spaces in the skull. But what’s emerged is that these air spaces have certain properties and functions,” said Witmer, Chang Professor of Paleontology in Ohio University’s College of Osteopathic Medicine.

Witmer and Ridgely examined skulls from two predators, Tyrannosaurus rex and Majungasaurus, and two ankylosaurian dinosaurs, Panoplosaurus and Euoplocephalus, both plant eaters with armored bodies and short snouts. For comparison, the scientists also studied scans of crocodiles and ostriches, which are modern day relatives of dinosaurs, as well as humans.

The analysis of the predatory dinosaurs revealed large olfactory areas, an arching airway that went from the nostrils to the throat, and many sinuses-the same cavities that give us sinus headaches. Overall, the amount of air space was much greater than the brain cavity.

The CT scans also allowed Witmer and Ridgely to calculate the volume of the bone, air space, muscle and other soft tissues to make an accurate estimate of how much these heads weighed when the animals were alive. A fully fleshed-out T. rex head, for example, weighed more than 1,100 pounds.

“That’s more than the combined weight of the whole starting lineup of the Cleveland Cavaliers,” Witmer said.

Witmer suggests that the air spaces helped lighten the load of the head, making it about 18 percent lighter than it would have been without all the air. That savings in weight could have allowed the predators to put on more bone-crushing muscle or even to take larger prey.

These sinus cavities also may have played a biomechanical role by making the bones hollow, similar to the hollow beams used in construction – both are incredibly strong but don’t weigh as much their solid counterparts. A light but strong skull enabled these predators to move their heads more quickly and helped them hold their large heads up on cantilevered necks, explained Witmer, who published the findings in a recent issue of The Anatomical Record.

Though most researchers have assumed that the nasal passages in armored dinosaurs would mimic the simple airways of the predators, Witmer and Ridgely found that these spaces actually were convoluted and complex. The passages were twisted and corkscrewed in the beasts’ snouts and didn’t funnel directly to the lungs or air pockets.

“Not only do these guys have nasal cavities like crazy straws, they also have highly vascular snouts. The nasal passages run right next to large blood vessels, and so there’s the potential for heat transfer. As the animal breathes in, the air passed over the moist surfaces and cooled the blood, and the blood simultaneously warmed the inspired air,” said Witmer, whose research is funded by the National Science Foundation. “These are the same kinds of physiological mechanisms we find all the time in warm-blooded animals today.”

These twisty nasal passages also acted as resonating chambers that affected how the ankylosaurs vocalized. The complex airways would have been somewhat different in each animal and might have given the dinosaurs subtle differences in their voices.

“It’s possible that these armored dinosaurs could recognize individuals based on the voice,” said Witmer, who noted that his research team’s studies of the inner ear revealed a hearing organ that probably had the capability to discriminate these subtle vocal nuances.

Though Witmer found few similarities between the dinosaur and human sinuses – our brain cavities take up much more space relative to our sinuses – the scientist did find a resemblance between the air spaces of the crocodiles and ostriches and the ancient beasts under study.

“Extra air space turns out to be a family characteristic,” he said, “but the sinuses may be performing different roles in different species. Scientists have tended to focus on things such as bones and muscle, and ignored these air spaces. If we’re going to decipher the mysteries of these extinct animals, maybe we need to figure out just why it is that these guys were such airheads.”

Note: This story has been adapted from a news release issued by the Ohio University

Huge Deposit of Jurassic Turtle Remains Found in China ?

October 30th, 2012

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“Bones upon bones, we couldn’t believe our eyes,” says Oliver Wings, paleontologist and guest researcher at the Museum für Naturkunde in Berlin. He was describing the spectacular find of some 1800 fossilized mesa chelonia turtles from the Jurassic era in China’s northwest province of Xinjiang. Wings and the University of Tübingen’s fossil turtle specialist, Dr. Walter Joyce, were working with Chinese paleontologists there in 2008.

Block of turtle layer

The results of their further work in 2009 and 2011 have just been published in the German journalNaturwissenschaften.

“This site has probably more than doubled the known number of individual turtles from the Jurassic,” says Walter Joyce. “Some of the shells were stacked up on top of one another in the rock.” It is what paleontologists call a “bone bed” – in this case consisting only of turtle remains.

Wings, Joyce and their team have made several expeditions to the arid region since 2007, finding fossil sharks, crocodiles, mammals and several dinosaur skeletons. Today one of the world’s driest regions, 160 million years ago Xinjiang was a green place of lakes and rivers, bursting with life. Yet the scientists have shown that even then, conditions were not always ideal, with climate change leading to seasonal drought – and this remarkable fossil find.

The turtles had gathered in one of the remaining waterholes during a very dry period, awaiting rain. Today’s turtles in Australia for instance do the same thing. But for the Xinjiang turtles, the rain came too late. Many of the turtles were already dead and their bodies rotting. When the water arrived, it came with a vengeance: a river of mud, washing the turtles and sediments along with it and dumping them in one place, as the paleontologists read the site and its layers of stone.

The large number of turtles allows the researchers to make a first statistical analysis of Asian turtles in the Jurassic period. Their simultaneous death and preservation makes it possible to compare variability, growth, and morphological differences among the species. The scientists are looking for sponsors to support further field studies and research into the dinosaur finds.

The above story is reprinted from materials provided byUniversitaet Tübingen.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Why Do the Caribbean Islands Arc? Movement of Earth Modeled to 3,000 Km Depth

October 29th, 2012

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The Caribbean islands have been pushed east over the last 50 million years, driven by the movement of Earth’s viscous mantle against the more rooted South American continent, reveals new research by geophysicists from USC.

The results, published August 19 inNature Geoscience, give us a better understanding of how continents resist the constant movement of Earth’s plates — and what effect the continental plates have on reshaping the surface of Earth.

Using earthquake data, USC earth scientists model the movement of the Earth to a depth of 3,000 kilometers and provide new insights into the strength of continents. Shown here is a tectonic map of the southeastern Caribbean. (Credit: Image/Courtesy Meghan Miller and Thorsten Becker)

“Studying the deep earth interior provides insights into how the Earth has evolved into its present form,” said Meghan S. Miller, assistant professor of earth sciences in the USC Dornsife College of Letters, Arts and Sciences, and lead author of the paper. “We’re interested in plate tectonics, and the southeastern Caribbean is interesting because it’s right near a complex plate boundary.”

Miller and Thorsten W. Becker, associate professor of earth sciences at USC Dornsife College, studied the margin between the Caribbean plate and the South American plate, ringed by Haiti, the Dominican Republic, Puerto Rico and a crescent of smaller islands including Barbados and St. Lucia.

But just like the First Law of Ecology (and time travel), when it comes to Earth, everything really is connected. So to study the motion of the South American continent and Caribbean plate, the researchers had to first model the entire planet — 176 models to be exact, so large that they took several weeks to compute even at the USC High Performance Computing Center.

For most of us, earthquakes are something to be dreaded. But for Miller and Becker they are a necessary source of data, providing seismic waves that can be tracked all over the world to provide an image of Earth’s deep interior like a CAT scan. The earthquake waves move slower or more quickly depending on the temperature and composition of the rock, and also depending on how the crystals within the rocks align after millions of years of being pushed around in mantle convection.

“If you can, you want to solve the whole system and then zoom in,” Becker said. “What’s cool about this paper is that we didn’t just run one or two models. We ran a lot, and it allowed us to explore different possibilities for how mantle flow might work.”

Miller and Becker reconstructed the movement of Earth’s mantle to a depth of almost 3,000 kilometers, upending previous hypotheses of the seismic activity beneath the Caribbean Sea and providing an important new look at the unique tectonic interactions that are causing the Caribbean plate to tear away from South America.

In particular, Miller and Becker point to a part of the South American plate — known as a “cratonic keel” — that is roughly three times thicker than normal lithosphere and much stronger than typical mantle. The keel deflects and channels mantle flow, and provides an important snapshot of the strength of the continents compared to the rest of Earth’s outer layers.

“Oceanic plates are relatively simple, but if we want to understand how the Earth works as a system — and how faults evolved and where the flow is going over millions of years — we also have to understand continental plates,” Becker said.

In the southeastern Caribbean, the interaction of the subducted plate beneath the Antilles island arc with the stronger continental keel has created the El Pilar-San Sebastian Fault, and the researchers believe a similar series of interactions may have formed the San Andreas Fault.

“We’re studying the Caribbean, but our models are run for the entire globe,” Miller said. “We can look at similar features in Japan, Southern California and the Mediterranean, anywhere we have instruments to record earthquakes.”

Fossils of First Feathered Dinosaurs from North America Discovered: Clues On Early Wing Uses

October 28th, 2012

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The ostrich-like dinosaurs in the original Jurassic Park movie were portrayed as a herd of scaly, fleet-footed animals being chased by a ferocious Tyrannosaurus rex. New research published in the journal Sciencereveals this depiction of these bird-mimic dinosaurs is not entirely accurate — the ornithomimids, as they are scientifically known, should have had feathers and wings.

The new study, led by paleontologists Darla Zelenitsky from the University of Calgary and François Therrien from the Royal Tyrrell Museum of Palaeontology, describes the first ornithomimid specimens preserved with feathers, recovered from 75 million-year-old rocks in the badlands of Alberta, Canada.

an artistic reconstruction of feathered ornithomimid dinosaurs found in Alberta. (Credit: Julius Csotonyi)

“This is a really exciting discovery as it represents the first feathered dinosaur specimens found in the Western Hemisphere,” says Zelenitsky, assistant professor at the University of Calgary and lead author of the study. “Furthermore, despite the many ornithomimid skeletons known, these specimens are also the first to reveal that ornithomimids were covered in feathers, like several other groups of theropod dinosaurs.”

The researchers found evidence of feathers preserved with a juvenile and two adults skeletons ofOrnithomimus, a dinosaur that belongs to the group known as ornithomimids. This discovery suggests that all ornithomimid dinosaurs would have had feathers.

The specimens reveal an interesting pattern of change in feathery plumage during the life of Ornithomimus. “This dinosaur was covered in down-like feathers throughout life, but only older individuals developed larger feathers on the arms, forming wing-like structures,” says Zelenitsky. “This pattern differs from that seen in birds, where the wings generally develop very young, soon after hatching.”

This discovery of early wings in dinosaurs too big to fly indicates the initial use of these structures was not for flight.

“The fact that wing-like forelimbs developed in more mature individuals suggests they were used only later in life, perhaps associated with reproductive behaviors like display or egg brooding,” says Therrien, curator at the Royal Tyrrell Museum and co-author of the study.

Until now feathered dinosaur skeletons had been recovered almost exclusively from fine-grained rocks in China and Germany. “It was previously thought that feathered dinosaurs could only fossilize in muddy sediment deposited in quiet waters, such as the bottom of lakes and lagoons,” says Therrien. “But the discovery of these ornithomimids in sandstone shows that feathered dinosaurs can also be preserved in rocks deposited by ancient flowing rivers.”

Because sandstone is the type of rock that most commonly preserves dinosaur skeletons, the Canadian discoveries reveal great new potential for the recovery of feathered dinosaurs worldwide.

The fossils will be on display this fall at the Royal Tyrrell Museum in Drumheller, Alberta.

Ancient Protein Preservation from dinosaur bone

October 26th, 2012

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A team of researchers from North Carolina State University and the Palo Alto Research Center (PARC) has found more evidence for the preservation of ancient dinosaur proteins, including reactivity to antibodies that target specific proteins normally found in bone cells of vertebrates. These results further rule out sample contamination, and help solidify the case for preservation of cells — and possibly DNA — in ancient remains.

Ancient Protein Preservation

Dr. Mary Schweitzer, professor of marine, earth and atmospheric sciences with a joint appointment at the North Carolina Museum of Natural Sciences, first discovered what appeared to be preserved soft tissue in a 67-million-year-oldTyrannosaurus Rex in 2005. Subsequent research revealed similar preservation in an even older (about 80-million-year-old)Brachylophosaurus canadensis. In 2007 and again in 2009, Schweitzer and colleagues used chemical and molecular analyses to confirm that the fibrous material collected from the specimens was collagen.

Schweitzer’s next step was to find out if the star-shaped cellular structures within the fibrous matrix were osteocytes, or bone cells. Using techniques including microscopy, histochemistry and mass spectrometry, Schweitzer demonstrates that these cellular structures react to specific antibodies, including one — a protein known as PHEX — that is found in the osteocytes of living birds. The findings appear online in Bone and were presented last week at the annual meeting of the Society of Vertebrate Paleontology.

“The PHEX finding is important because it helps to rule out sample contamination,” Schweitzer says. “Some of the antibodies that we used will react to proteins found in other vertebrate cells, but none of the antibodies react to microbes, which supports our theory that these structures are surviving osteocytes. Additionally, the antibody to PHEX will only recognize and bind to one specific site only found in mature bone cells from birds. These antibodies don’t react to other proteins or cells. Because so many other lines of evidence support the dinosaur/bird relationship, finding these proteins helps make the case that these structures are dinosaurian in origin.”

Schweitzer and her team also tested for the presence of DNA within the cellular structures, using an antibody that only binds to the “backbone” of DNA. The antibody reacted to small amounts of material within the “cells” of both the T. rex and the B. canadensis. To rule out the presence of microbes, they used an antibody that binds histone proteins, which bind tightly to the DNA of everything except microbes, and got another positive result. They then ran two other histochemical stains which fluoresce when they attach to DNA molecules. Those tests were also positive. These data strongly suggest that the DNA is original, but without sequence data, it is impossible to confirm that the DNA is dinosaurian.

“The data thus far seem to support the theory that these structures can be preserved over time,” Schweitzer says. “Hopefully these findings will give us greater insight into the processes of evolutionary change.”

Dr. Marshall Bern, from PARC, performed the mass spectrometry. Former NC State doctoral student Timothy Cleland and research assistant Wenxia Zheng also contributed to the work, which was funded by grants from the National Science Foundation and the David and Lucile Packard Foundation.

100-Million-Year-Old Coelacanth Fish Discovered in Texas Is New Species from Cretaceous

October 25th, 2012

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A new species of coelacanth fish has been discovered in Texas. The species is now the youngest coelacanth from Texas; fish jaw and cranial material indicate a new family — Dipluridae — that was evolutionary transition between two previously known families.

Pieces of tiny fossil skull found in Fort Worth have been identified as 100 million-year-old coelacanth bones, according to paleontologist John F. Graf, Southern Methodist University, Dallas.

A fossil discovered in Texas is a new species of coelacanth fish. Paleontologist John Graf, Southern Methodist University, Dallas, identified the skull as a 100 million-year-old coelacanth, making it the youngest discovered in Texas. (Credit: Image courtesy of Southern Methodist University)

The coelacanth has one of the longest lineages — 400 million years — of any animal. It is the fish most closely related to vertebrates, including humans.

The SMU specimen is the first coelacanth in Texas from the Cretaceous, said Graf, who identified the fossil. The Cretaceous geologic period extended from 146 million years ago to 66 million years ago.

Graf named the new coelacanth species Reidus hilli.

Coelacanths have been found on nearly every continent

Reidus hilli is now the youngest coelacanth identified in the Lone Star State.

Previously the youngest was a 200 million-year-old coelacanth from the Triassic. Reidus hilli is the first coelacanth ever identified from the Dallas-Fort Worth area.

Coelacanth fossils have been found on every continent except Antarctica. Few have been found in Texas, Graf said.

The coelacanth fish has eluded extinction for 400 million years. Scientists estimate the coelacanth reached its maximum diversity during the Triassic.

The coelacanth was thought to have gone extinct about 70 million years ago. That changed, however, when the fish rose to fame in 1938 after live specimens were caught off the coast of Africa. Today coelacanths can be found swimming in the depths of the Indian Ocean.

Chart courtesy of the British Geological Survey.

Closest living fish to all vertebrates alive on land ”

These animals have one of the longest lineages of any vertebrates that we know,” Graf said.

The SMU specimen demonstrates there was greater diversity among coelacanths during the Cretaceous than previously known.

“What makes the coelacanth interesting is that they are literally the closest living fish to all the vertebrates that are living on land,” he said. “They share the most recent common ancestor with all of terrestrial vertebrates.”

Coelacanths have boney support in their fins, which is the predecessor to true limbs.

“Boney support in the fins allows a marine vertebrate to lift itself upright off the sea floor,” Graf said, “which would eventually lead to animals being able to come up on land.”

Texas coelacanth, Reidus hilli, represents a new species and a new family

Graf identified Reidus hilli from a partial skull, including gular plates, which are bones that line the underside of the jaw.

“Coelacanths are not the only fish that have gular plates, but they are one of the few that do,” Graf said. “In fact, the lenticular shape of these gular plates is unique to coelacanths. That was the first indicator that we had a fossil coelacanth.”

Reidus hilli was an adult fish of average size for the time in which it lived, said Graf. While modern coelacanths can grow as large as 3 meters, Reidus hilli was probably no longer than 40 centimeters. Its tiny skull is 45 millimeters long by 26 millimeters wide, or about 1.75 inches long by 1 inch wide.

Reidus hilli‘s total body size is typical of the new family of coelacanths, Dipluridae, which Graf describes and names. He chose the name for the least primitive coelacanth in the family, Diplurus, which lived during the Triassic.

“Reidus hilli helped me tie a group of coelacanths together into what I identify as a new family of coelacanths,” he said. “This family represents a transition between the two large groups of youngest living coelacanths from the fossil record, Mawsoniidae and Latimeriidae.”

Diplurid coelacanths are typically smaller than the two families with which they are most closely associated, Mawsoniidae and Latimeriidae. Mawsoniidae and Latimeriidae both have late Cretaceous members reaching large body sizes, ranging from 1 meter to 3 meters in total body length, Graf said.

Reidus hilli provides clues to missing coelacanth historyReidus hilli is named, in part, for the amateur collector who discovered the fish, Robert R. Reid.

A Fort Worth resident, Reid has collected fossils for decades. He found the fossil specimen while walking some land that had been prepared for construction of new homes. Reid noticed the fossil lying loose on the ground in a washed out gully created by run-off.

Following Graf’s analysis, Reid was surprised to learn he’d collected a coelacanth — and a new species.

“When I found it, I could tell it was a bone but I didn’t think it was anything special,” said Reid, recalling the discovery. “I certainly didn’t think it was a coelacanth.”

At the time, SMU paleontologist Louis L. Jacobs recommended to Reid that he donate the fossil and have it scientifically identified. Reid gave the fossil to SMU’s Shuler Museum of Paleontology in the Roy M. Huffington Department of Earth Sciences.

“It is astounding what can be learned from the discoveries that people like Rob Reid make in their own backyards,” said Jacobs, an SMU professor of earth sciences and president of SMU’s Institute for the Study of Earth and Man. “The discovery of living coelacanths in the Indian Ocean after being presumed extinct for 70 million years highlights one of the great mysteries of ocean life. Where were they all that time? The new fossil from Texas is a step toward understanding this fascinating history.”

Reidus hilli is the latest of many fossils Reid has discovered. Others also have been named for him.

Reidus hilli discovered in Duck Creek Formation of North Texas

Reidus hilli came from the fossil-rich Duck Creek Formation, which is a layer-cake band of limestone and shale about 40 feet thick.

The fossil was found in marine sediments, Graf said. It is one of many marine fossils found in the North Texas area, which 100 million years ago was covered by the Western Interior Seaway that divided North America from the Gulf of Mexico to the Arctic Ocean.

“That is unique to younger coelacanths,” Graf said. “The oldest coelacanths were usually found in freshwater deposits and it wasn’t until the Cretaceous that we start seeing this transition into a more marine environment.”

Fossil also named for Robert T. Hill, “Father of Texas Geology”

Graf also named the fossil for Robert T. Hill, a geologist with the U.S. Geological Survey who led surveys of Texas during the 1800s. Hill described much of the geology of Texas, including the Duck Creek Formation. Hill is acclaimed as the “Father of Texas Geology.”

Identification of Reidus hilli brings the number of coelacanth species worldwide to 81, including two that are alive today. Sources report that 229 living coelacanths have been caught since 1938.