WFS News: Sclerocormus parviceps reveal rapid evolution after mass extinction ?

Two hundred and fifty million years ago, life on earth was in a tail-spin–climate change, volcanic eruptions, and rising sea levels contributed to a mass extinction that makes the death of the dinosaurs look like child’s play. Marine life got hit hardest–96% of all marine species went extinct. For a long time, scientists believed that the early marine reptiles that came about after the mass extinction evolved slowly, but the recent discovery of a strange new fossil brings that view into question.

In a paper published in Scientific Reports, paleontologists describe a new marine reptile, Sclerocormus parviceps, an ichthyosauriform that’s breaking all the rules about what ichthyosaurs are like.

This is Sclerocormus parviceps, the newly described marine reptile. Credit: Copyright Da-yong Jiang

This is Sclerocormus parviceps, the newly described marine reptile.Credit: Copyright Da-yong Jiang

Ichthyosaurs were a massive group of marine reptiles that lived around the time of the earliest dinosaurs. Most of them looked a little bit like today’s dolphins–streamlined bodies, long beak-like snouts, and powerful tail fins. But the new species is something of a black sheep. It has a short snout (its species name even means “small skull”), and instead of a tail with triangular flukes (think of a fish’s tail-fins), it had a long, whip-like tail without big fins at the end. And while many ichthyosaurs had conical teeth for catching prey,Sclerocormus was toothless and instead seems to have used its short snout to create pressure and suck up food like a syringe. In short, it’s really different from most of its relatives, and that tells scientists something important about evolution.

Sclerocormus tells us that ichthyosauriforms evolved and diversified rapidly at the end of the Lower Triassic period,” explains Olivier Rieppel, The Field Museum’s Rowe Family Curator of Evolutionary Biology. “We don’t have many marine reptile fossils from this period, so this specimen is important because it suggests that there’s diversity that hasn’t been uncovered yet.”

The way this new species evolved into such a different form so quickly sheds light on how evolution actually works. “Darwin’s model of evolution consists of small, gradual changes over a long period of time, and that’s not quite what we’re seeing here. These ichthyosauriforms seem to have evolved very quickly, in short bursts of lots of change, in leaps and bounds,” says Rieppel.

Animals like Sclerocormus that lived just after a mass extinction also reveal how life responds to huge environmental pressures. “We’re in a mass extinction right now, not one caused by volcanoes or meteorites, but by humans,” explains Rieppel. “So while the extinction 250 million years ago won’t tell us how to solve what’s going on today, it does bear on the evolutionary theory at work. How do we understand the recovery and rebuilding of a food chain, of an ecosystem? How does that get fixed, and what comes first?”

This study was conducted by scientists at Peking University, University of California, Davis, the Anhui Geological Museum, the Università degli Studi di Milano, The Field Museum, National Museums Scotland, the Chinese Academy of Sciences, and the Smithsonian’s National Museum of Natural History.

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Ref:Da-Yong Jiang, Ryosuke Motani, Jian-Dong Huang, Andrea Tintori, Yuan-Chao Hu, Olivier Rieppel, Nicholas C. Fraser, Cheng Ji, Neil P. Kelley, Wan-Lu Fu & Rong Zhang. A large aberrant stem ichthyosauriform indicating early rise and demise of ichthyosauromorphs in the wake of the end-Permian extinction. Scientific Reports, 2016

WFS NEWS : Impact Crators

Impact craters reveal one of the most spectacular geologic process known to human beings. During the past 3.5 billion years, it is estimated that more than 80 bodies, larger than the dinosaur-killing asteroid that struck the Yucatan Peninsula 66 million years ago, have bombarded Earth. However, tectonic processes, weathering, and burial quickly obscure or destroy craters. For example, if Earth weren’t so dynamic, its surface would be heavily cratered like the Moon or Mercury.

The Barringer Meteorite Crater.

                                                                                   The Barringer Meteorite Crater.

Work by B.C. Johnson and T.J. Bowling predicts that only about four of the craters produced by these impacts could persist until today, and geologists have already found three such craters (larger than 170 km in diameter). Their study, published online for Geology on 22 May 2014, indicates that craters on Earth cannot be used to understand Earth’s bombardment history.

Formation of a simple crater. Image Credit: Illustration from an educational poster, Geological Effects of Impact Cratering, David A. Kring, NASA Univ. of Arizona Space Imagery Center, 2006. Modified from a figure in Traces of Catastrophe, Bevan M. French, 1998 – modified from a figure in Impact Cratering on the Earth, Richard A. F. Grieve, Scientific American, v. 262, pp. 66–73, 1990.

Formation of a simple crater. Image Credit: Illustration from an educational poster, Geological Effects of Impact Cratering, David A. Kring, NASA Univ. of Arizona Space Imagery Center, 2006. Modified from a figure in Traces of Catastrophe, Bevan M. French, 1998 – modified from a figure in Impact Cratering on the Earth, Richard A. F. Grieve, Scientific American, v. 262, pp. 66–73, 1990.

Johnson and Bowling write, however, that layers of molten rock blasted out early in the impact process may act as better records of impacts — even after the active Earth has destroyed the source craters. The authors suggest that searches for these impact ejecta layers will be more fruitful for determining how many times Earth was hit by big asteroids than searches for large craters.

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Major earthquake threat from the Riasi fault in the Himalayas ?

New geologic mapping in the Himalayan mountains of Kashmir between Pakistan and India suggests that the region is ripe for a major earthquake that could endanger the lives of as many as a million people.

Scientists have known about the Riasi fault in Indian Kashmir, but it wasn’t thought to be as much as a threat as other, more active fault systems. However, following a magnitude 7.6 earthquake in 2005 on the nearby Balakot-Bagh fault in the Pakistan side of Kashmir — which was not considered particularly dangerous because it wasn’t on the plate boundary — researchers began scrutinizing other fault systems in the region.

Scientist studying the Riasi fault note that the resulting earthquake may be large - as much as magnitude 8.0 or greater (Google Maps)

Scientist studying the Riasi fault note that the resulting earthquake may be large – as much as magnitude 8.0 or greater (Google Maps)

What they found is that the Riasi fault has been building up pressure for some time, suggesting that when it does release or “slip,” the resulting earthquake may be large — as much as magnitude 8.0 or greater.

Results of the new study, which was funded by the National Science Foundation, have been accepted for publication by the Geological Society of America Bulletin, and published online.

“What we set out to learn was how much the fault has moved in the last tens of thousands of years, when it moved, and how different segments of the fault move,” said Yann Gavillot, lead author on the study who did much of the work as a doctoral student at Oregon State University. “What we found was that the Riasi fault is one of the main active faults in Kashmir, but there is a lack of earthquakes in the more recent geologic record.

“The fault hasn’t slipped for a long time, which means the potential for a large earthquake is strong. It’s not a question of if it’s going to happen. It’s a matter of when.”

There is direct evidence of some seismic activity on the fault, where the researchers could see displacement of Earth where an earthquake lifted one section of the fault five or more meters — possibly about 4,000 years ago. Written records from local monasteries refer to strong ground-shaking over the past several thousand years.

But the researchers don’t have much evidence as to how frequent major earthquakes occur on the fault, or when it may happen again.

“The Riasi fault isn’t prominent on hazard maps for earthquake activity, but those maps are usually based more on the history of seismic activity rather than the potential for future events,” said Andrew Meigs, a geology professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the study. “In actuality, the lack of major earthquakes heightens the likelihood that seismic risk is high.”

The researchers say 50 percent of the seismic “budget” for the fault can be accounted for with the new information. The budget is determined over geologic time by the movement of the tectonic plates. In that region, the India tectonic plate is being subducted beneath the Asia plate at a rate of 14 millimeters a year; the Riasi fault accounts for half of that but has no records of major earthquakes since about 4,000 years ago, indicating a major slip, and earthquake, is due.

“In the last 4,000 years, there has only been one major event on the Riasi fault, so there is considerable slip deficit,” Meigs said. “When there is a long gap in earthquakes, they have the potential to be bigger unless earthquakes on other faults release the pressure valve. We haven’t seen that. By comparison, there have been about 16 earthquakes in the past 4,000 years in the Cascadia Subduction Zone off the Northwest coast of the United States.”

An anticipated earthquake generated on the Riasi Fault would have a major impact on Jammu. Image-Google Earth

An anticipated earthquake generated on the Riasi Fault would have a major impact on Jammu. Image-Google Earth

Gavillot said a major earthquake at the Riasi fault could have a major impact on Jammu, the Indian capital of the Indian state of Jammu and Kashmir, which has a population of about 1.5 million people. Another 700,000 people live in towns located right on the fault.

“There are also several dams on the Chenab River near the fault, and a major railroad that goes through or over dozens of tunnels, overpasses and bridges,” Gavillot said. “The potential for destruction is much greater than the 2005 earthquake.”

The 2005 Kashmir earthquake killed about 80,000 people in Pakistan and India.

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Citation:Oregon State University. “New study finds major earthquake threat from the Riasi fault in the Himalayas.” ScienceDaily. ScienceDaily, 18 May 2016. <www.sciencedaily.com/releases/2016/05/160518133832.htm

Spiclypeus shipporum: New horned dinosaur species with ‘spiked shield’

A chance fossil discovery in Montana a decade ago has led to the identification of an audacious new species of horned dinosaur. The international research team that described the plant-eating dinosaur was led by a scientist at the Canadian Museum of Nature. The results are published today in the online science journal PLOS ONE.

The museum now houses the specimen in its national fossil collection, which includes some of the best examples of horned dinosaurs in the world. Museum palaeontologist Dr. Jordan Mallon completed the scientific analysis that pinned down the dinosaur as a new species. It is one among a growing number of newly discovered ceratopsids (four-legged dinosaurs generally characterized by horns on the face and elaborate head frills).

Artist illustration by Mike Skrepnick of Spiclypeus shipporum, a newly described genus and species of horned dinosaur. Here, the dinosaur roams across a floodplain 76 million years ago. The fossil was discovered in 2005 in the Judith River Formation in Montana. Credit: Illustration by Mike Skrepnick © Mike Skrepnick.

Artist illustration by Mike Skrepnick of Spiclypeus shipporum, a newly described genus and species of horned dinosaur. Here, the dinosaur roams across a floodplain 76 million years ago. The fossil was discovered in 2005 in the Judith River Formation in Montana.
Credit: Illustration by Mike Skrepnick © Mike Skrepnick.

Mallon has bestowed the scientific name Spiclypeus shipporum (spi-CLIP-ee-us ship-OR-um) on the dinosaur, which lived about 76 million year ago.Spiclypeus is a combination of two Latin words meaning “spiked shield,” referring to the impressive head frill and triangular spikes that adorn its margins. The name shipporum honours the Shipp family, on whose land the fossil was found near Winifred, Montana.

About half of the skull, as well as parts of the dinosaur’s legs, hips and backbone had been preserved in the silty hillside that once formed part of an ancient floodplain.

“This is a spectacular new addition to the family of horned dinosaurs that roamed western North America between 85 and 66 million years ago,” explains Mallon, who collaborated with researchers in Canada and the United States. “It provides new evidence of dinosaur diversity during the Late Cretaceous period from an area that is likely to yield even more discoveries.”

 Holotype cranial Material and Cranial Reconstruction of Machairoceratops cronusi (UMNH VP 20550) gen. et sp. nov. Recovered cranial elements of Machairoceratops in right-lateral view, shown overlain on a ghosted cranial reconstruction (A). The jugal, squamosal and braincase are all photo-reversed for reconstruction purposes. Machairoceratops cranial reconstruction in dorsal (B), and right-lateral (C) views. Green circle overlain on the ventral apex of the jugal highlights the size of the epijugal contact scar (ejcs). Abbreviations: BC, braincase; boc, basioccipital; bpt, basipterygoid process; ej, epijugal; ejcs, epijugal contact scar; j, jugal; lpr, lateral parietal ramus; lsb, laterosphenoid buttress; m, maxilla; n, nasal; o, orbit, oc, occipital condyle; oh, orbital horn; on, otic notch; p, parietal; pf, parietal fenestra; pm, premaxilla; po, postorbital; poc, paroccipital process; p1, epiparietal locus p1; sq, squamosal. Scale bars = 0.5 m. show less

Holotype cranial Material and Cranial Reconstruction of Machairoceratops cronusi (UMNH VP 20550) gen. et sp. nov.
Recovered cranial elements of Machairoceratops in right-lateral view, shown overlain on a ghosted cranial reconstruction (A). The jugal, squamosal and braincase are all photo-reversed for reconstruction purposes. Machairoceratops cranial reconstruction in dorsal (B), and right-lateral (C) views. Green circle overlain on the ventral apex of the jugal highlights the size of the epijugal contact scar (ejcs). Abbreviations: BC, braincase; boc, basioccipital; bpt, basipterygoid process; ej, epijugal; ejcs, epijugal contact scar; j, jugal; lpr, lateral parietal ramus; lsb, laterosphenoid buttress; m, maxilla; n, nasal; o, orbit, oc, occipital condyle; oh, orbital horn; on, otic notch; p, parietal; pf, parietal fenestra; pm, premaxilla; po, postorbital; poc, paroccipital process; p1, epiparietal locus p1; sq, squamosal. Scale bars = 0.5 m.

What sets Spiclypeus shipporum apart from other horned dinosaurs such as the well-known Triceratops is the orientation of the horns over the eyes, which stick out sideways from the skull. There is also a unique arrangement to the bony “spikes” that emanate from the margin of the frill–some of the spikes curl forward while others project outward.

“In this sense, Spiclypeus is transitional between more primitive forms in which all the spikes at the back of the frill radiate outward, and those such asKosmoceratops in which they all curl forward,” says Mallon.

While the fossil now has a scientific moniker, it is more commonly known by its nickname “Judith,” after the Judith River geological formation where it was found. Until it was purchased by the museum in 2015, the fossil had remained in the official possession of Dr. Bill Shipp, who found it while exploring his newly acquired property in 2005.

Shipp invested time and money to excavate and prepare the bones, aided by volunteers and palaeontologists including the PLOS ONE study co-authors Chris Ott and Peter Larson. “Little did I know that the first time I went fossil hunting I would stumble on a new species,” explains Shipp, a retired nuclear physicist who became a fossil enthusiast after moving to his dinosaur rich area of Montana. “As a scientist, I’m really pleased that the Canadian Museum of Nature has recognized the dinosaur’s value, and that it can now be accessed by researchers around the world.”

Apart from the horns and frill bones that helped define Judith as a new species, close examination of some of its other bones reveal a story of a life lived with pain. Judith’s upper arm bone (humerus) shows distinct signs of arthritis and osteomyelitis (bone infection)–determined following analysis by Dr. Edward Iuliano, a radiologist at the Kadlec Regional Medical Cener, in Richland, Washington.

“If you look near the elbow, you can see great openings that developed to drain an infection. We don’t know how the bone became infected, but we can be sure that it caused the animal great pain for years and probably made its left forelimb useless for walking,” explains Mallon. Despite this trauma, analysis of the annual growth rings inside the dinosaur’s bones by the Royal Ontario Museum’s Dr. David Evans suggest it lived to maturity. The dinosaur would have been at least 10 years old when it died.

Mallon and his team note that there are now nine well-known dinosaur species (including Spiclypeus shipporum), from Montana’s Judith River Formation. Some are also found in Alberta, which has a much richer fossil record, but others such as Spiclypeus are unique to Montana. Significantly, Mallon says that none of the species are shared with more southerly states, suggesting that dinosaur faunas in western North America were highly localized about 76 million years ago. Mallon’s prior research has shown that such species-rich communities may have been enabled by dietary specializations among the herbivores, a phenomenon more commonly known as niche partitioning.

A public exhibit about Spiclypeus shipporum, will open May 24 at the Canadian Museum of Nature in Ottawa. It will include a reconstruction of the dinosaur’s skull, the diseased humerus, and other bones from this amazing fossil find.

Citation:Canadian Museum of Nature. “New horned dinosaur species with ‘spiked shield’.” ScienceDaily. ScienceDaily, 18 May 2016. <www.sciencedaily.com/releases/2016/05/160518152908.htm

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WFS news: How the Hawaiian-Emperor seamount chain became so bendy

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The physical mechanism causing the unique, sharp bend in the Hawaiian-Emperor seamount chain has been uncovered in a collaboration between the University of Sydney and the California Institute of Technology (Caltech).

Led by a PhD candidate at the University of Sydney’s School of Geosciences, researchers used the Southern Hemisphere’s most highly integrated supercomputer to reveal flow patterns deep in the Earth’s mantle — just above the core — over the past 100 million years. The flow patterns explain how the enigmatic bend in the Hawaiian-Emperor seamount chain arose.

True to the old adage — as above, so below — the Sydney-US collaboration found the shape of volcanic seamount chains (chains of mostly extinct volcanoes), including Hawaii, is intimately linked to motion near the Earth’s core.

This is a Hawaii-Emperor seamount chain. Credit: University of Sydney

This is a Hawaii-Emperor seamount chain.Credit: University of Sydney

The findings of PhD candidate Rakib Hassan and fellow researchers including Professor Dietmar Müller from the University’s EarthByte Group, are being published in Nature.

Mr Hassan explained: “Until now, scientists believed the spectacular 60° bend in the Hawaiian seamount chain — not found in any other seamount chains — was related to a change in plate motion combined with a change in flow direction in the shallow mantle, the layer of thick rock between the Earth’s crust and its core.

“These findings suggest the shape of volcanic seamount chains record motion in the deepest mantle, near the Earth’s core. The more coherent and rapid the motion deep in the mantle, the more acute its effects are on the shape of seamount chains above,” he said.

Although solid, the mantle is in a state of continuous flow, observable only over geological timescales. Vertical columns of hot and buoyant rock rising through the mantle from near the core are known as mantle plumes. Volcanic seamount chains such as Hawaii were created from magma produced near the surface by mantle plumes. Moving tectonic plates sit above the mantle and carry newly formed seamounts away from the plume underneath — the oldest seamounts in a chain are therefore furthest away from the plume.

“We had an intuition that, since the north Pacific experienced a prolonged phase where large, cold tectonic plates uninterruptedly sank into the mantle, the flow in the deepest mantle there would be very different compared to other regions of the Earth,” Mr Hassan said.

One of the most contentious debates in geoscience has centred on whether piles of rock in the deep mantle — to which plumes are anchored — have remained stationary, unaffected by mantle flow over hundreds of millions of years.The new research shows the shapes of these piles have changed through time and their shapes can be strongly dependent on rapid, coherent flow in the deep mantle.

Between 50-100 million years ago, the edge of the pile under the north Pacific was pushed rapidly southward, along with the base of Hawaii’s volcanic plume, causing it to tilt. The plume became vertical again once the motion of its base stopped; this dramatic start-stop motion resulted in the seamount chain’s sharp bend.

Using Australia’s National Computational Infrastructure’s supercomputer Raijin, the team created high-resolution three-dimensional simulations of mantle evolution over the past 200 million years to understand the coupling between convection in the deep Earth and volcanism.

Mr Hassan said the simulations were guided by surface observations — similar to meteorologists applying past measurements to predict the weather.

“These simulations required millions of central processing unit (CPU) hours on the supercomputer over the course of the project,” he said.

Professor Müller concluded: “Our results help resolve a major enigma of why volcanic seamount chains on the same tectonic plate can have very different shapes.

“It is now clear that we first need to understand the dynamics of the deepest ‘Underworld’, right above the core, to unravel the history of volcanism at Earth’s surface,” said Professor Müller.

Watch the animation here https://youtu.be/Xy5kHjAHXec

Citation:University of Sydney. “How the spectacular Hawaiian-Emperor seamount chain became so bendy.” ScienceDaily. ScienceDaily, 11 May 2016. <www.sciencedaily.com/releases/2016/05/160511142351.htm

WFS NEWS : chemistry of Earth’s atmosphere 2.7 billion years ago

Using the oldest fossil micrometeorites — space dust — ever found, Monash University-led research has made a surprising discovery about the chemistry of Earth’s atmosphere 2.7 billion years ago.

The findings of a new study published today in the journal Nature — led by Dr Andrew Tomkins and a team from the School of Earth, Atmosphere and Environment at Monash, along with scientists from the Australian Synchrotron and Imperial College, London — challenge the accepted view that Earth’s ancient atmosphere was oxygen-poor. The findings indicate instead that the ancient Earth’s upper atmosphere contained about the same amount of oxygen as today, and that a methane haze layer separated this oxygen-rich upper layer from the oxygen-starved lower atmosphere.

This is one of 60 micrometeorites extracted from 2.7 billion year old limestone, from the Pilbara region in Western Australia. These micrometeorites consist of iron oxide minerals that formed when dust particles of meteoritic iron metal were oxidised as they entered Earth's atmosphere, indicating that the ancient upper atmosphere was surprisingly oxygen-rich. Credit: Andrew Tomkins

This is one of 60 micrometeorites extracted from 2.7 billion year old limestone, from the Pilbara region in Western Australia. These micrometeorites consist of iron oxide minerals that formed when dust particles of meteoritic iron metal were oxidised as they entered Earth’s atmosphere, indicating that the ancient upper atmosphere was surprisingly oxygen-rich.Credit: Andrew Tomkins

“Using cutting-edge microscopes we found that most of the micrometeorites had once been particles of metallic iron — common in meteorites — that had been turned into iron oxide minerals in the upper atmosphere, indicating higher concentrations of oxygen than expected,” Dr Tomkins said.

“This was an exciting result because it is the first time anyone has found a way to sample the chemistry of the ancient Earth’s upper atmosphere,” Dr Tomkins said.

Imperial College researcher Dr Matthew Genge — an expert in modern cosmic dust — performed calculations that showed oxygen concentrations in the upper atmosphere would need to be close to modern day levels to explain the observations.

“This was a surprise because it has been firmly established that the Earth’s lower atmosphere was very poor in oxygen 2.7 billion years ago; how the upper atmosphere could contain so much oxygen before the appearance of photosynthetic organisms was a real puzzle,” Dr Genge said.

Dr Tomkins explained that the new results suggest the Earth at this time may have had a layered atmosphere with little vertical mixing, and higher levels of oxygen in the upper atmosphere produced by the breakdown of CO 2 by ultraviolet light.

“A possible explanation for this layered atmosphere might have involved a methane haze layer at middle levels of the atmosphere. The methane in such a layer would absorb UV light, releasing heat and creating a warm zone in the atmosphere that would inhibit vertical mixing,” Dr Tomkins said.

“It is incredible to think that by studying fossilised particles of space dust the width of a human hair, we can gain new insights into the chemical makeup of Earth’s upper atmosphere, billions of years ago.” Dr Tomkins said.

Dr Tomkins outlined next steps in the research.

“The next stage of our research will be to extract micrometeorites from a series of rocks covering over a billion years of Earth’s history in order to learn more about changes in atmospheric chemistry and structure across geological time. We will focus particularly on the great oxidation event, which happened 2.4 billion years ago when there was a sudden jump in oxygen concentration in the lower atmosphere.”

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mosasaurs were warm-blooded?

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Mosasaurs — an extinct group of aquatic reptiles that thrived during the Late Cretaceous period — possibly were “endotherms,” or warm-blooded creatures, a paper co-written by a UA professor suggests.

Dr. Alberto Perez-Huerta’s paper on endothermic mosasaurs — co-written with now-graduated doctoral student Dr. T. Lynn Harrell Jr. and Dr. Celina Suarez of the University of Arkansas — was published in a March issue ofPalaeontology, a journal published by the Palaeontological Association.

Fossilize teeth of a mosasaur (stock image). Mosasurs were large aquatic reptiles that went extinct at the end of the Cretaceous period, about 66 million years ago. Credit: © smuki / Fotolia

Fossilize teeth of a mosasaur (stock image). Mosasurs were large aquatic reptiles that went extinct at the end of the Cretaceous period, about 66 million years ago.Credit: © smuki / Fotolia

Mosasurs were large aquatic reptiles that went extinct at the end of the Cretaceous period, about 66 million years ago. The paper focuses on a debate in the paleontological community over how mosasaurs employed “thermaregulation,” or how they controlled their body heat — whether mosasaurs were endotherms (warm-blooded) or ectotherms, cold-blooded creatures taking their body temperature from the surrounding sea.

A paper published in 2010 suggested that mosasaurs were ectotherms, but Harrell and Perez-Huerta thought otherwise.

“There was a paper published in Science in 2010 reporting the thermoregulation in marine reptiles at the time of the dinosaurs focusing on the iconic extinct taxa: ichthyosaurs, plesiosaurs and mosasaurs,” said Perez-Huerta, a UA associate professor of geology. “This conclusion bothered me a bit because there was not a warm-blooded member organism used for comparison, and we know that size can matter in terms of thermoregulation.”

Body outlines and skeletons of mosasaur genera analysed in this study for scale (left) and representative dentaries for each genus (right). Figures redrawn and modified from Russell (1967) and Lindgren et al. (2010, 2011). Scale bars represent 3 m (left) and 10 cm (right).

Body outlines and skeletons of mosasaur genera analysed in this study for scale (left) and representative dentaries for each genus (right). Figures redrawn and modified from Russell (1967) and Lindgren et al. (2010, 2011). Scale bars represent 3 m (left) and 10 cm (right).

The study by Harrell (lead author), Perez-Huerta and Suarez used an oxygen isotope analysis on mosasaurs fossils in the collection of UA’s Alabama Museum of Natural History and compared them to fossils of known cold-blooded animals, such as fish and turtles, from the same period, as well as the bones of such contemporary warm-blooded organisms represented by birds — “true” endotherms.

“Lynn came up with good ideas for two chapters of his dissertation, already published as well,” Perez-Huerta said. “We discussed looking for endothermy in mosasaurs given his knowledge on this group of extinct marine reptiles, the large collections of these fossil organisms in the Alabama Museum of Natural History and the scientific controversy related to the Science paper.”

The study states that mosasurs’ body-temperatures compared to the temperatures of modern, warm-blooded sea birds, suggesting that mosausurs were indeed warm-blooded. The study found that this tendency toward higher body temperature held despite the size of the particular mosasur genus or species — body size (gigantothermy) didn’t matter.

“The findings of the present study support that mosasaurs were able to maintain a higher internal temperature independent of the ambient seawater temperature and were likely endotherms, with values closer to contemporaneous fossil and modern birds and higher than fish and turtles,” the researchers said. “Although there are small differences of body temperature among mosasaur genera, these are independent of size, and thus inferred body mass, suggesting that mosasaurs were not gigantotherms.”

Perez-Huerta noted that the study was possible thanks to the Alabama Museum of Natural History’s extensive collection.

“This research study was the ‘perfect storm’ because Lynn is a very good vertebrate paleontologist, amazing collections at the natural-history museum — one of the best in North America for mosasaurs,” Perez-Huerta said. “There are great outcroppings containing mosasaur fossils in Alabama. This research could not have been possible with the great fossil collections housed at the history museum on the University’s campus, and the collaboration of their staff to facilitate our access.”

Citation:T. Lynn Harrell, Alberto Pérez-Huerta, Celina A. Suarez. Endothermic mosasaurs? Possible thermoregulation of Late Cretaceous mosasaurs (Reptilia, Squamata) indicated by stable oxygen isotopes in fossil bioapatite in comparison with coeval marine fish and pelagic seabirds. Palaeontology, 2016; 59 (3).Science daily.

 


Laser-Stimulated Fluorescence in Paleontology

Highlighting and identifying fossilized structures can be difficult whether it is bone, soft tissue such as skin, muscle and internal organs, or integument such as scales and feathers. Historically, multiple methods have been used to highlight structures for photography, including cross-lighting, polarized light , camera filters, and ultraviolet (UV) light . Cross-lighting can highlight structures that are difficult to see in direct light. Polarized light can help to enhance image contrast. UV light is capable of causing minerals (e.g. bone [hydroxyapatite]) to fluoresce, and can even highlight soft tissue to some extent . This paper describes a next-generation method of fluorescing minerals using specific wavelengths of light produced by a laser and corresponding imaging through the use of laser-blocking longpass camera filters . This method is herein named Laser-stimulated fluorescence (LSF).

Feather under reflected and matrix fluoresced illumination. Green River Formation feather using identical images under different lighting conditions. A, Reflected light microscopy, only barbs are visible. B, Polarized light, some traces of barbules. C, Laser-stimulated fluorescence of matrix behind the carbon film backlights the feather and renders barbules visible across the entire field of view. Scale bar 0.5 mm.

Feather under reflected and matrix fluoresced illumination.
Green River Formation feather using identical images under different lighting conditions. A, Reflected light microscopy, only barbs are visible. B, Polarized light, some traces of barbules. C, Laser-stimulated fluorescence of matrix behind the carbon film backlights the feather and renders barbules visible across the entire field of view. Scale bar 0.5 mm.

For many decades UV light has been used at night to find and collect fluorescent mineral specimens, which are prized for their wide variation in color . The field of biology has made tremendous scientific advances through the use of laser-induced fluorescence mostly through the widespread use of confocal laser microscopes . In paleontology, UV light has seen increasing use in recent years where the resulting fluorescence can often reveal structures and patterns not seen under white light. The typical UV light source consists of commonly available standard fluorescent lamps with low wattage and a wavelength of 364 nanometers (nm) . Greater amounts of UV flux on the specimen will cause fluorescent minerals to become more conspicuous, allowing for easier photographic documentation, sometimes with the aid of UV filters (e.g. Hoya brand) . The limited variety of detectable fluorescence in fossils has been a primary limitation in the past using standard UV bulbs .

 Feather structure comparison using white light, polarized and laser illumination. A second Green River Formation feather specimen under: A, white light, B, polarized light, and C, laser illumination. Scale bar 0.2 mm.

Feather structure comparison using white light, polarized and laser illumination.
A second Green River Formation feather specimen under: A, white light, B, polarized light, and C, laser illumination. Scale bar 0.2 mm.

The technique presented here utilizes laser illumination to stimulate fluorescence which offers an order of magnitude improvement in the signal-to-noise ratio over standard UV light. The irradiance of a 20 watt UV fluorescent lamp is about 510 milliwatts per square centimeter (mWcm-2) at a distance of 20 centimeters from the target , but the irradiance of a ½ watt laser is on the order of 4000–8000 mWcm-2 . This results in detectable fluorescence of many hard-to-fluoresce mineral types which typically remain dark under standard UV. This advantage can be leveraged when other factors are accounted for. For instance, matching the correct laser line with one of the specimen’s absorption bands provides more effective excitation of the fluorescence in a sample. Furthermore, using the right optical filter that matches one of the fluorescence bands of the specimen would improve contrast in the fluorescence image.

Automated fossil sorter. Proof-of-concept prototype automated micro-fossil picker. The feeder bowl guides a stream of matrix under the laser while a video camera detects ‘blobs’ of a certain size and brightness. Fluorescing fossils are guided down a tube into a tray by a puff of compressed air

Automated fossil sorter.
Proof-of-concept prototype automated micro-fossil picker. The feeder bowl guides a stream of matrix under the laser while a video camera detects ‘blobs’ of a certain size and brightness. Fluorescing fossils are guided down a tube into a tray by a puff of compressed air

Each color of laser emits a different wavelength of light, which will excite fossils and matrix from different rock units in different ways, as the case histories that follow will indicate. Again, LSF techniques depend on the wavelength of light used, the filter used, and the inherent fluorescent properties of the rocks under study. The exact methodology used, therefore, is going to vary depending on these properties.

Fluorescent black light vs. blue laser. A direct comparison between a 15 watt fluorescent UV light illuminating all the fossils at a distance of 7cm, and a 447nm 500mw laser stimulating the specimens in the upper left corner. A, Specimens from the Lance Formation exhibit very low reactivity under fluorescent UVA bulbs. B, Specimens from the White River Formation typically fluoresce very well. This demonstrates that the intensity of laser stimulation can influence low reactivity specimens to fluorescence several orders of magnitude better than specimens known to fluoresce well under UV bulbs. Scale bar 1 cm

Fluorescent black light vs.blue laser. A direct comparison between a 15 watt fluorescent UV light illuminating all the fossils at a distance of 7cm, and a 447nm 500mw laser stimulating the specimens in the upper left corner. A, Specimens from the Lance Formation exhibit very low reactivity under fluorescent UVA bulbs. B, Specimens from the White River Formation typically fluoresce very well. This demonstrates that the intensity of laser stimulation can influence low reactivity specimens to fluorescence several orders of magnitude better than specimens known to fluoresce well under UV bulbs. Scale bar 1 cm

Laser-induced fluorescence imaging performed through confocal laser-scanning microscopy (CLSM) has been used in micropaleontology to study the morphology and cellular anatomy of fossils in situ, at micron-scale resolution, and even in three-dimensions . LSF is a simplified and more accessible version of CLSM that uses simpler laser beam scanning and data acquisition systems, and lacks a confocal hole. However, the LSF technique provides its own unique advantages in studying macroscopic paleontological specimens including the compactness and low cost of its setup, its fast data acquisition rate and its high sensitivity compared to UV-stimulated fluorescence. The purpose of this paper is to describe the laser-stimulated fluorescence (LSF) imaging technique and to formalize its use in paleontology in the hope that new and more efficient modes of discovery will be possible.

Citation:Kaye TG, Falk AR, Pittman M, Sereno PC, Martin LD, Burnham DA, et al. (2015) Laser-Stimulated Fluorescence in Paleontology. PLoS ONE 10(5): e0125923. doi:10.1371/journal.pone.0125923

Key: WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

Sarmientosaurus : A New titanosaurian dinosaur

Scientists have discovered Sarmientosaurus musacchioi, a new species of titanosaurian dinosaur, based on an complete skull and partial neck fossil unearthed in Patagonia, Argentina, according to a study published April 26, 2016 in the open-access journal PLOS ONE by Rubén Martínez from the Laboratorio de Paleovertebrados of the Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), Argentina, and colleagues.

Titanosaurs, a type of sauropod, ranged in size from the weight of a cow to that of the largest sperm whale. These plant-eaters have long necks and tails and may have been the most common large herbivores in the Southern Hemisphere landmasses during the Cretaceous. Despite their abundance, the skulls of these animals, critical to deciphering certain aspects of their biology, are exceedingly rare. Of the 60-plus named titanosaurs, only four are represented by nearly complete or semi-complete skulls. Using computerized tomography (CT) imaging, the authors of this study closely examined well-preserved, anatomically ‘primitive’ skull and neck fossils from Sarmientosaurus.

Sarmientosaurus head posture, brain & eye (WitmerLab): Digital renderings of the skull and reconstructed brain endocast and eye of the new titanosaurian dinosaur species Sarmientosaurus musacchioi. At left is the skull rendered semi-transparent in left side view, showing the relative size and position of the brain endocast (in blue, pink, yellow, and red) and the inferred habitual head posture. At center is the isolated brain endocast in left side view, and at right is a left/front view of the skull showing the reconstructed eyeball and its associated musculature. Scale bar equals five centimeters. Credit: WitmerLab, Ohio University

Sarmientosaurus head posture, brain & eye (WitmerLab): Digital renderings of the skull and reconstructed brain endocast and eye of the new titanosaurian dinosaur species Sarmientosaurus musacchioi. At left is the skull rendered semi-transparent in left side view, showing the relative size and position of the brain endocast (in blue, pink, yellow, and red) and the inferred habitual head posture. At center is the isolated brain endocast in left side view, and at right is a left/front view of the skull showing the reconstructed eyeball and its associated musculature. Scale bar equals five centimeters.   Credit: WitmerLab, Ohio University

The researchers found that the Sarmientosaurus brain was small relative to its enormous body, typical of sauropods. However, they also found evidence of greater sensory capabilities than most other sauropods. They suggest that Sarmientosaurus had large eyeballs and good vision, and that the inner ear may have been better tuned for hearing low-frequency airborne sounds compared to other titanosaurs. Moreover, the balance organ of the inner ear indicates that this dinosaur may have habitually held its head with the snout facing downward, possibly to feed primarily on low-growing plants. “Discoveries like Sarmientosaurus happen once in a lifetime,” says study leader Rubén Martínez. “That’s why we studied the fossils so thoroughly, to learn as much about this amazing animal as we could.”

Sarmientosaurus musacchioi is named for the town of Sarmiento in Chubut Province, which is close to the discovery site. The species name also honors the late Dr. Eduardo Musacchio, a paleontologist and professor at the UNPSJB and friend to Dr. Martínez and other team members.

Citation:PLOS. “Newly discovered titanosaurian dinosaur from Argentina, Sarmientosaurus: Approximately 95-million-year-old complete sauropod skull examined, possibly exceptional sensory capabilities.

Key: WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

How deep sea creatures survive asteroid strike that wiped out the dinosaurs : World Fossil Society News

WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev,

A team led by experts at Cardiff University has provided new evidence to explain why deep sea creatures were able to survive the catastrophic asteroid strike that wiped out the dinosaurs 65m years ago.

Like the dinosaurs themselves, giant marine reptiles, invertebrates and microscopic organisms became extinct after the catastrophic asteroid impact in an immense upheaval of the world’s oceans, yet deep sea creatures managed to survive.

This has puzzled researchers as it is widely believed that the asteroid impact cut off the food supply in the oceans by destroying free-floating algae and bacteria.

However, in a study published in the April issue of the journal Geology, a team led by researchers from Cardiff University’s School of Earth and Ocean Sciences provides strong evidence suggesting that some forms of algae and bacteria were actually living in the aftermath of the asteroid disaster, and that they acted as a constant, sinking, slow trickle of food for creatures living near the seafloor.

The team were able to draw these conclusions by analysing new data from the chemical composition of the fossilised shells of sea surface and seafloor organisms from that period, taken from drilling cores from the ocean floor in the South Atlantic.

Artist's impression of large asteroid closing in on Earth (stock image). Credit: © Mopic / FotoliaClose

                           Artist’s impression of large asteroid closing in on Earth (stock image).Credit: © Mopic / FotoliaClose

This gave the researchers an idea of the flux, or movement, of organic matter from the sea surface to the seafloor in the aftermath of the asteroid strike, and led them to conclude that a slow trickle of food was constantly being delivered to the deep ocean.

Furthermore, the team were able to calculate that the food supply in the ocean was fully restored around 1.7m years after the asteroid strike, which is almost half the original estimates, showing that marine food chains bounced back quicker than originally thought.

Heather Birch, a Cardiff University PhD from the School of Earth and Ocean Sciences who led the study, said: “The global catastrophe that caused the extinction of the dinosaurs also devastated ocean ecosystems. Giant marine reptiles met their end as did various types of invertebrates such as the iconic ammonites.

“Our results show that despite a wave of massive and virtually instantaneous extinctions among the plankton, some types of photosynthesising organisms, such as algae and bacteria, were living in the aftermath of the asteroid strike.

“This provided a slow trickle of food for organisms living near the ocean floor which enabled them to survive the mass extinction, answering one of the outstanding questions that still remained regarding this period of history.

“Even so, it took almost two million years before the deep sea food supply was fully restored as new species evolved to occupy ecological niches vacated by extinct forms.”

Many scientists currently believe that the mass extinction of life on Earth around 65m years ago was caused by a 110km-wide asteroid that hit Mexico’s Yucatán Peninsula. It is believed the debris from impact starved Earth of the Sun’s energy and, once settled, led to greenhouse gases locking in the Sun’s heat and causing temperatures to rise drastically.

This period of darkness followed by soaring heat, known as the Cretaceous-Paleogene boundary, was thought to obliterate almost half of the world’s species.

Scientists also claim that the impact of the asteroid would have filled Earth’s atmosphere with sulphur trioxide, subsequently creating a gas cloud that would have caused a mass amount of sulphuric acid rain to fall in just a few days, making the surface of the ocean too acidic for upper ocean creatures to live.

Cardiff University. “‘Trickle of food’ helped deep sea creatures survive asteroid strike that wiped out the dinosaurs.” ScienceDaily. ScienceDaily, 14 April 2016. <www.sciencedaily.com/releases/2016/04/160414081843.htm

Key: WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev