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

Fossil Study Helps Pinpoint Extinction Risks for Ocean Animals: When It Comes to Ocean Extinctions, Range Size Matters Most

October 24th, 2012

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What makes some ocean animals more prone to extinction than others? A new study of marine fossils provides a clue.

An analysis of roughly 500 million years of fossil data for marine invertebrates reveals that ocean animals with small geographic ranges have been consistently hard hit — even when populations are large, the authors report.

The oceans represent more than 70% of Earth’s surface. But because monitoring data are harder to collect at sea than on land, we know surprisingly little about the conservation status of most marine animals. By using the fossil record to study how ocean extinctions occurred in the past, we may be better able to predict species’ vulnerability in the future.

Venericardia densata, extinct species of clam. The location is Claiborne Bluff on the Alabama River, Monroe County, Alabama. The age was middle Eocene (48.6 – 37.2 million years ago) Lisbon Formation. (Credit: Photo by Paul Harnik)

“If the patterns we observed in the fossil record hold for species living today, our results suggest that species with large populations but small ranges are at greater risk of extinction than we might have expected,” said study co-author Paul Harnik of the National Evolutionary Synthesis Center.

Researchers have long assumed that rare animals are more likely to die out. But “rare” could mean multiple things.

The word “rare” could be applied to species that have restricted geographic ranges, or small populations, or that tolerate a narrow range of habitats, or any combination thereof, the authors say.

False killer whales, for example, are considered rare because they occur in small numbers, even though they’re found in oceans throughout the world.

Erect-crested penguins, on the other hand, are considered rare because they’re geographically restricted to remote islands off the coast of New Zealand — even though they’re fairly abundant where they occur.

Harnik and colleagues Jonathan Payne of Stanford University and Carl Simpson of the Museum für Naturkunde in Berlin wanted to know which aspects of rarity best predict why some species survive and others die out.

“It’s only through the fossil record where we have a long-term record of extinction where we can really see whether those relationships hold up,” Harnik said.

To find out, the team scoured a fossil database for marine invertebrates that inhabited the world’s oceans from 500 million years ago to the present — a dataset that included 6500 genera of sea urchins, sand dollars, corals, snails, clams, oysters, scallops, brachiopods and other animals.

When the researchers looked for links between extinction rate and measures of rarity, they found that the key predictor of extinction risk for ocean animals was small geographic range size.

Habitat breadth played a secondary role, whereas population size had little effect. The result: Ocean animals that both had small geographic ranges and tolerated a narrow suite of habitats were six times more likely to go extinct than common animals were.

“Environmental changes are unlikely to affect all areas equally, or all individuals at the same time in the same way. If something terrible happens to some part of a species’ range, then at least some populations will still survive,” Harnik explained.

Life in the sea was once thought to be less prone to extinction than life on land. But with global warming, overfishing, and ocean acidification pushing sea life to its limits, growing evidence suggests otherwise.

“The findings don’t mean that when populations dwindle we shouldn’t worry about them,” Harnik said.

“But the take home message is that reductions in range size — such as when a species’ habitat is destroyed or degraded — could mean a big increase in long-term extinction risk, even if population sizes in the remaining portions of the species’ range are still relatively large.”

The results will be published this week in the journalProceedings of the Royal Society B

Fossil Fishes from China Provide First Evidence of Dermal Pelvic Girdles in Osteichthyans

October 22nd, 2012

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The pectoral and pelvic girdles support paired fins and limbs, and have transformed significantly in the diversification of gnathostomes or jawed vertebrates (including osteichthyans, chondrichthyans, acanthodians and placoderms). For instance, changes in the pectoral and pelvic girdles accompanied the transition of fins to limbs as some osteichthyans (a clade that contains the vast majority of vertebrates – bony fishes and tetrapods) ventured from aquatic to terrestrial environments. The fossil record shows that the pectoral girdles of early osteichthyans (e.g., Lophosteus, Andreolepis, Psarolepis and Guiyu) retained part of the primitive gnathostome pectoral girdle condition with spines and/or other dermal components. However, very little is known about the condition of the pelvic girdle in the earliest osteichthyans. Living osteichthyans, like chondrichthyans (cartilaginous fishes), have exclusively endoskeletal pelvic girdles, while dermal pelvic girdle components (plates and/or spines) have so far been found only in some extinct placoderms and acanthodians. Consequently, whether the pectoral and pelvic girdles are primitively similar in osteichthyans cannot be adequately evaluated, and phylogeny-based inferences regarding the primitive pelvic girdle condition in osteichthyans cannot be tested against available fossil evidence.

The gnathostomes or jawed vertebrates comprise the extant osteichthyans (bony fishes and tetrapods) and chondrichthyans (cartilaginous fishes) along with the extinct placoderms and acanthodians . Girdle-supported paired fins and limbs characterize all jawed vertebrates, and have undergone significant transformation in the course of gnathostome diversification. The pectoral girdles of gnathostomes primitively combine dermal and endoskeletal elements, as in jawless osteostracans even though the osteostracan pectoral girdles are fused to the cranium. For instance, the pectoral girdle in crown osteichthyans (actinopterygians and sarcopterygians) has an endoskeletal scapulocoracoid attached to the inner surface of the cleithrum (one of the encircling dermal bones of the pectoral girdle). However, the primitive condition for pelvic girdles is less clear, resulting from the scarcity of articulated early gnathostome postcrania and the absence of girdle-supported pelvic fins in all known jawless fishes. Both living osteichthyans and chondrichthyans have exclusively endoskeletal pelvic girdles . Until recently, the presence of pelvic girdles with substantial dermal components (large dermal plates) was thought to be restricted to some placoderms (arthrodires, ptyctodonts, acanthothoracids and antiarchs) while pelvic fin spines alone were found in some acanthodians . The purported monophyly of both of these fossil gnathostome ‘classes’ is currently under scrutiny, with most recent phylogenies assigning some or all acanthodians to the osteichthyan stem , while resolving the placoderms (either as a monophyletic group or as a paraphyletic assemblage) at the base of the jawed vertebrate radiation. Inferences from these phylogenies would predict that stem osteichthyans more crownward than Acanthodes should have at most the pelvic girdles similar to those in acanthodians (i.e., an endoskeletal girdle with a dermal fin spine). Until now, the earliest osteichthyan materials have yielded very little information regarding the primitive condition of pelvic girdles among osteichthyans, making it difficult to test phylogeny-based inferences against the known fossil record or to explore how and when the living osteichthyans may have acquired their exclusively endoskeletal pelvic girdles.

As the first known occurrence in any osteichthyans, here we describe pelvic girdles with substantial dermal components (plates and spines) in two early bony fishes, Guiyu oneiros andPsarolepis romeri , from Yunnan, China. Guiyu and Psarolepis have been placed as stem sarcopterygians in earlier studies , even though they manifested combinations of features found in both sarcopterygians and actinopterygians (e.g. pectoral girdle structures, the cheek and operculo-gular bone pattern, and scale articulation). When Guiyu was first described based on an exceptionally well-preserved holotype specimen, it also revealed a combination of osteichthyan and non-osteichthyan features, including spine-bearing pectoral girdles and spine-bearing median dorsal plates found in non-osteichthyan gnathostomes as well as cranial morphology and derived macromeric squamation found in crown osteichthyans. In addition, Guiyuprovided strong corroboration for the attempted restoration of Psarolepis romeri based on disarticulated cranial, cheek plate, shoulder girdle and scale materials . The incongruent distribution of Guiyu and Psarolepis features across different groups (actinopteryians vs sarcopterygians, osteichthyans vs non-osteichthyans) poses special challenges to attempts at polarizing the plesiomorphic osteichthyan and gnathostome characters and reconstructing osteichthyan morphotype . The phylogenetic analysis in Zhu et al. assigned two possible positions for Psarolepis, either as a stem sarcopterygian or as a stem osteichthyan. Basden et al. suggested that Psarolepis is more likely a stem sarcopterygian based on the comparison of braincase morphology with an actinopterygian-like osteichthyan Ligulalepis. The phylogenetic analysis in Zhu et al. placed Guiyu in a cluster with Psarolepis and Achoania as stem sarcopterygians, with Meemannia and Ligulalepis as more basal sarcopterygians, and Andreolepis and Lophosteus as stem osteichthyans.

New articulated specimen of Guiyu oneiros

Although previous studies of Guiyu and Psarolepis have advanced our understanding of early osteichthyan morphologies beyond what was previously known from Andreolepis, Lophosteus ,Ligulalepis and Dialipina , no pelvic girdle components were identified or described at the time, and the primitive condition of pelvic girdles in osteichthyans remained unknown until recently. The situation started to change when a new articulated specimen of Guiyu oneiros was collected from the Late Ludlow (Silurian) Kuanti Formation, Yunnan, China. Observations of this new specimen, re-examination of the holotype of Guiyu oneiros, and studies of previously unidentified disarticulated specimens of Psarolepis form the basis for the finding reported below. As the first evidence for the presence of dermal pelvic girdles in osteichthyans, the pelvic girdles in Guiyu and Psarolepis reveal an unexpected morphology that stands in stark contrast to the inferences from published phylogenetic analyses (except for one of two alternative positions of Psarolepis in Zhu et al. , and appear to resemble those of placoderms rather than either the acanthodians or, indeed, any other previously known osteichthyans.

Min Zhu¹^*, Xiaobo Yu¹^,², Brian Choo¹, Qingming Qu¹^,³,Liantao Jia¹, Wenjin Zhao¹, Tuo Qiao¹, Jing Lu¹

1 Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China, 2 Department of Biological Sciences, Kean University, New Jersey, United States of America, 3 Subdepartment of Evolutionary Organismal Biology, Department of Physiology and Developmental Biology, Uppsala University, Uppsala, Sweden

Scientists Identify Likely Origins of Vertebrate Air Breathing

October 21st, 2012

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University of Alaska Fairbanks scientists have identified what they think is the ancestral trait that allowed for the evolution of air breathing in vertebrates.

They will present their research at the 42nd annual meeting of the Society for Neuroscience Oct. 17 in New Orleans.

Screenshot of a video recorded in Michael Harris’ lab shows the difference between gill ventilation and a ‘cough’ in a larval lamprey. (Credit: Image courtesy of University of Alaska Fairbanks)
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“To breathe air with a lung you need more than a lung, you need neural circuitry that is sensitive to carbon dioxide,” said Michael Harris, a UAF neuroscientist and lead researcher on a project investigating the mechanisms that generate and control breathing.

“It’s the neural circuitry that allows air-breathing organisms to take in oxygen, which cells need to convert food into energy, and expel the waste carbon dioxide resulting from that process,” he said. “I’m interested in where that carbon-dioxide-sensitive neural circuit, called a rhythm generator, came from.”

Harris and colleagues think that air breathing likely evolved in an ancestral vertebrate that did not have a lung, but did have a rhythm generator.

“We try to find living examples of primitive non-air-breathing ancestors, like lamprey, and then look for evidence of a rhythm generator that did something other than air breathing,” Harris said.

Lampreys are ancient fish that have characteristics similar to the first vertebrates. They do not have lungs and do not breathe air. As larvae, they live in tubes dug into soft mud and breathe and feed by pumping water through their bodies. When mud or debris clogs a lamprey’s tube, they use a cough-like behavior to expel water and clear the tube. A rhythm generator in their brain controls that behavior.

A video clip (http://www.youtube.com/watch?v=c7b3pl9pK_o) recorded in Harris’ lab shows the difference between gill ventilation and a ‘cough’ in a larval lamprey. The ‘cough’ occurs at about the 9 second mark.

“We thought the lamprey ‘cough’ closely resembled air breathing in amphibians,” said Harris. “When we removed the brains from lampreys and measured nerve activity that would normally be associated with breathing, we found patterns that resemble breathing and found that the rhythm generator was sensitive to carbon dioxide.”

Air breathing evolved in fish and allowed the movement of vertebrates to land and the evolution of reptiles, birds and mammals. Without a carbon-dioxide-sensitive rhythm generator, the structure that would become the lung might not have worked as a lung.

“The evolution of lung breathing may be a repurposing of carbon dioxide sensitive cough that already existed in lungless vertebrates, like the lamprey,” said Harris.

Harris and collaborators Barbara Taylor, a UAF neuroscientist, and their lab technician Megan Hoffman, also study Sudden Infant Death Syndrome and hope understanding the evolutionary origin of breathing will provide insights into their SIDS research.

JURASSIC PARK WON’T HAPPEN: DINO DNA DEAD

October 20th, 2012

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In “Jurassic Park,” scientists extract 80-million-year-old dino DNA from the bellies of mosquitoes trapped in amber. Researchers may never be able to extract genetic material that old and bring a T. rex back to life, but a new study suggests DNA can survive in fossils longer than previously believed.

The oldest DNA samples ever recovered are from insects and plants in ice cores in Greenland up to 800,000 years old. But researchers had not been able to determine the oldest possible DNA they could get from the fossil record because DNA’s rate of decay had remained a mystery.

An artist’s rendition of an eagle attacking two extinct New Zealand moa.

Now scientists in Australia report they’ve been able to estimate this rate based on a comparison of DNA from 158 fossilized leg bones from three species of the moa, an extinct group of flightless birds that once lived in New Zealand. The bones date between 600 and 8,000 years old and importantly all come from the same region.

Temperatures, oxygenation and other environmental factors make it difficult to detect a basic rate of degradation, researcher Mike Bunce, from Murdoch University’s Ancient DNA lab in Perth, explained in a statement.

“The moa bones however have allowed us to study the comparative DNA degradation because they come from different ages from a region where they have all experienced the same environmental conditions,” Bunce said.

Based on this study, Bunce and his team put DNA’s half-life at 521 years, meaning half of the DNA bonds would be broken down 521 years after death, and half of the remaining bonds would be decayed another 521 years after that, and so on. This rate is 400 times slower than simulation experiments predicted, the researchers said, and it would mean that under ideal conditions, all the DNA bonds would be completely destroyed in bone after about 6.8 million years.

“If the decay rate is accurate then we predict that DNA fragments of sufficient length will preserve in frozen fossil bone of around one million years in age,” Bunce said.

But he cautioned that more research is needed to examine the other variables in the breakdown of DNA.

“Other factors that impact on DNA preservation include storage time following excavation, soil chemistry and even the time of year when the animal died,” Bunce said in a statement. “We hope to refine predictions of DNA survival by more accurately mapping how DNA fragments decay across the globe.”

The study was published Oct. 10 in the journal Proceedings of the Royal Society B.

Image courtesy:An artist’s rendition of an eagle attacking two extinct New Zealand moa. John Megahan

‘Time-Capsule’ Japanese Lake Sediment Advances Radiocarbon Dating for Older Objects

October 19th, 2012

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A new series of radiocarbon measurements from Japan’s Lake Suigetsu will give scientists a more accurate benchmark for dating materials, especially for older objects, according to a research team that included Oxford University’s Radiocarbon Accelerator Unit.

The research team extracted cores of beautifully preserved layers of sediment, containing organic material (such as tree leaf and twig fossils), from the bottom of the Japanese lake where they had lain undisturbed for tens of thousands of years. As an article in the journalScience explains, the findings are hugely significant because they provide a much more precise way to examine radiocarbon ages of organic material for the entire 11,000-53,000-year time range. For example, archaeologists should now be able to pinpoint more accurately the timing of the extinction of Neanderthals or the spread of modern humans into Europe.

At the Oxford Radiocarbon Accelerator Unit, Professor Christopher Ramsey with his doctoral student Richard Staff and chemist Dr Fiona Brock worked with two other radiocarbon laboratories (the NERC facility at East Kilbride, Scotland, and Groningen in the Netherlands) on the radiocarbon record from the lake. This research is part of a large international research team, led by Professor Takeshi Nakagawa of Newcastle University, studying the cores for clues about past climate and environmental change.

Radiocarbon is continuously produced in the upper atmosphere. These roughly constant levels of radiocarbon from the atmosphere are then incorporated into all living organisms. Once the organisms die, the radioactive isotope decays at a known rate, so by measuring the radiocarbon levels remaining in samples today scientists can work out how old things are. However, the complication in the calculation is that the initial amounts of radiocarbon in the environment, which are in turn incorporated into growing organisms, vary slightly from year to year and between different parts of the global carbon cycle.

The radiocarbon in the leaf fossils preserved in the sediment of Lake Suigetsu comes directly from the atmosphere and, as such, is not affected by the processes that can slightly change the radiocarbon levels found in marine sediments or cave formations. Before the publication of this new research, the longest and most important radiocarbon dating records came from such marine sediments or cave formations, but these needed to be corrected. At last, the cores from Lake Suigetsu provide a more complete, direct record of radiocarbon from the atmosphere without the need for further correction.

The cores are unique: they display layers in the sediment for each year, giving scientists the means of counting back the years. These counts are compared with over 800 radiocarbon dates from the preserved fossil leaves.The only other direct record of atmospheric carbon comes from tree rings, but this only goes back to 12,593 years ago. The Lake Suigetsu record extends much further to 52,800 years ago, increasing the direct radiocarbon record by more than 40,000 years.

‘In most cases the radiocarbon levels deduced from marine and other records have not been too far wrong. However, having a truly terrestrial record gives us better resolution and confidence in radiocarbon dating,’ said Professor Ramsey. ‘It also allows us to look at the differences between the atmosphere and oceans, and study the implications for our understanding of the marine environment as part of the global carbon cycle.’

To construct a radiocarbon record from Lake Suigetsu, Professor Ramsey and his colleagues measured radiocarbon from terrestrial plant fragments spaced throughout the core. The research team also counted the light and dark layers throughout the glacial period to place the radiocarbon measurements in time. Many of the layers were too fine to be distinguished by the naked eye, so the researchers used a microscope, as well as a method called X-ray fluorescence that identifies chemical changes along the core.

A record of year-to-year changes in radiocarbon levels in the atmosphere, such as those found in a sediment core, must be ‘anchored’ in time by assigning some part of it an absolute age. The researchers did this by matching the first 12,200 years of their record with the tree-ring data, a well-established record that begins in the present. Ramsey and colleagues also lined up segments of their data with those of other records from the same time periods and found that they generally aligned.

‘This record will not result in major revisions of dates. But, for example in prehistoric archaeology, there will be small shifts in chronology in the order of hundreds of years,’ said Professor Ramsey. ‘Such changes can be very significant when you are trying to examine human responses to climate that are often dated by other methods, such as through layer counting from the Greenland ice cores. For the first time we have a more accurate calibrated time-scale, which will allow us to answer questions in archaeology that we have not had the resolution to address before.’

Generally, researchers use a composite record called IntCal to determine the ages of objects, based on their radiocarbon measurements. The IntCal record uses data from multiple sources, including marine records, stalagmites and stalactites, and tree rings. It is expected that the Suigetsu data will be incorporated into the latest iteration of IntCal, which is due to be released within the next few months.

SEA MONSTER ‘PREDATOR X’ GETS OFFICIAL NAME

October 19th, 2012

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It’s official: A giant, marine reptile that roamed the seas roughly 150 million years ago is a new species, researchers say. The animal, now named Pliosaurus funkei, spanned about 40 feet (12 meters) and had a massive 6.5-foot-long (2 m) skull with a bite four times as powerful as Tyrannosaurus rex.

The huge pliosaur fossils had to be cast in plaster before being removed from the Svalbard site

“They were the top predators of the sea,” said study co-author Patrick Druckenmiller, a paleontologist at the University of Alaska Museum. “They had teeth that would have made a T. rex whimper.”

Combined with other fossil finds, the newly discovered behemoth skeletons of P. funkei paint a picture of an ancient Jurassic-era ocean filled with giant predators.

In 2006, scientists unearthed two massive pliosaurskeletons in Svalbard, Norway, a string of islands halfway between Europe and the North Pole. The giant creatures, one of which was dubbed Predator X at the time, looked slightly different from other pliosaurs discovered in England and France over the last century and a half.

Now, after years of painstaking analysis of the jaw, vertebrae and forelimbs, the researchers have determined that Predator X is in fact a new species, and they have officially named it for Bjorn and May-Liss Funke, volunteers who first discovered the fossils.

The pliosaurs, marine reptiles that prowled the seas 160 million to 145 million years ago during the Jurassic period, had short necks, tear-shaped bodies and four large, paddle-shaped limbs that let them “fly through the water,” Druckenmiller told LiveScience.

The new species likely lived closer to 145 million years ago and ate plesiosaurs, related long-necked, small-headed reptiles.

The new analysis shows P. funkei had proportionally longer front paddles than other pliosaurs, as well as slightly different vertebrae shape and different spacing of teeth within the jaw, Druckenmiller said.

In 2008, scientists initially estimated that Predator X could have been up to 50 feet (15 m) long. The current study suggests the creature is smaller than that, but still bigger than the largest living apex predator, the killer whale, which tops out at about 30 feet (9 m) long, Druckenmiller said.

The Pliosaurus funkei fossils were just two of nearly 40 specimens discovered at the Svalbard site. In the Oct. 12 issue of the Norwegian Journal of Geology, the authors also describe two new ichthyosaurs, or dolphinlike reptiles, the longest-necked Jurassic-era plesiosaur on record, and several invertebrates.

Together, the fossils suggest an ancient Arctic sea teeming with fearsome predators and invertebrate fauna, said study co-author Jorn Hurum of the University of Oslo in an email.

“It’s not just that we found a new species, we’ve been discovering a whole ecosystem,” Druckenmiller said.

Mayfly With Springtail Hitchhiker: Amber Specimen — 16 Million Years Old — Reveals Unknown Animal Behaviors

October 18th, 2012

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Stunning images, including video footage, from a CT scan of amber have revealed the first evidence of any creature using an adult mayfly for transport.

Researchers at the University of Manchester say this 16-million-year-old hitchhiker most likely demonstrates activity that is taking place today but has never previously been recorded.

Mayfly in Amber Specimen

Entombed in amber the tiny springtail can be seen resting in a v-shaped depression at the base of one of the mayfly’s wings. It appears to have secured itself for transport using its prehensile antennae.

Dr David Penney and colleagues from the Faculty of Life Sciences and the School of Materials used a high resolution CT scanner to take over 3,000 X-rays from different angles.

The scientists then created slices, showing the fossil in cross sections. From these slices 3D digital images of the springtail were made so an accurate analysis of its behaviour could be conducted.

Dr Penney says: “The images are really impressive. This pioneering approach to studying fossils has allowed us an insight into the behaviour of one of the world’s most prevalent organisms.”

Springtails are minute creatures (usually only 1-2mm long) related to true insects. They’re found around the world in great numbers, including here in the UK. Gardeners will recognise them as the tiny insects that hop around when soil is disturbed. They readily colonize newly-formed islands but very little is known about how they manage to migrate. One of the reasons is that they are incredibly nervous creatures and have an astonishing ability to leap away from danger using a springing organ (the furca) on the underside of the abdomen, which makes observing them in life very difficult.

Interestingly, when the 3D image of the springtail in amber is magnified it’s possible to see that the springtail is very slightly detached (by just 50 micrometres) from the mayfly. This suggests it was attempting to spring away as the amber set around it.

Only one previous case of phoresy (the transportation of one organism by another) has been recorded for springtails. This was found in a piece of Baltic amber where five springtails were hooked in a row on the leg of a harvestman arachnid.

It was this discovery in 2010 which prompted Dr Penney to take a closer look at his own specimen. “I had initially thought the creature on the mayfly may have been a tiny nymphal pseudoscorpion, as they are known to use other creatures for transport, and this behaviour is not uncommon to see in amber. I was interested in the fact that this was the first time a creature had been found on an adult mayfly but I didn’t truly appreciate the significance of my find until I used the CT scanner and was able to identify the animal as a springtail.”

Phoresy in adult mayflies has never before been recorded. They live for just a short period of time from one hour to a few days depending on the species. The primary function of the adult stage is reproduction and they are unable to feed. This makes it very difficult to study mayflies in their natural habitat and record instances of phoresy.

The amber specimen encasing the mayfly and the springtail provides an accurate snapshot of behaviour that scientists wouldn’t otherwise be able to record, highlighting one important application of the fossil record for understanding the present. The near perfect condition of the mayfly demonstrates that it died instantaneously and wasn’t moved far from where it rested when the resin ran over it. Equally the position of the springtail resting on the back of the mayfly and the fact that it is in contact with the creature means the pair were unlikely to have been brought together by the resin as it moved down the tree.

The details of Dr Penney’s research has been published in the journal, PLOS ONE. More analysis of amber using CT scans is continuing.

Dr Penney says: “The CT scan allows us to build up a 3D image that catches minute details of the animal. We can rotate the image to see parts of the creature that are obscured when looking from the outside in. In effect, we are able to digitally dissect the fossil without causing any damage to it whatsoever. This technology has revolutionised how we study fossils and the findings are incredibly exciting.”

The Science Behind Those Eye-Popping Northern Lights

October 17th, 2012

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Northern night skies have recently been alive with light. Those shimmering curtains get their start about 93 million miles away, on the sun.

An aurora borealis (aurora australis in the Southern Hemisphere) is precipitated by explosions on the surface of the sun, sometimes starting as solar flares, said Robert Nemiroff, an astrophysicist at Michigan Technological University and coauthor of NASA’s Astronomy Picture of the Day website.

Northern lights

These flares release a burst of charged particles, or plasma, into the solar system. When they come our way, they whack into Earth’s magnetosphere, which is made up of its own stream of charged particles. That collision causes particles to break free of the magnetosphere and cascade towar Earth’s magnetic field lines, usually traveling toward the poles.

“The aurorae happen when these high-energy particles bap into atoms and molecules in the Earth’s atmosphere, typically oxygen,” Nemiroff said. Light is emitted as part of the reaction.

Those particles can also wreak havoc. “The plasma cloud can cause the Earth’s magnetic field to fluctuate,” Nemiroff said. “At worst, that can knock out satellites and even power grids.”

Aurorae can happen anytime, but it’s no surprise they are happening now.

“We are nearing the solar maximum, which is when the sun is at its most active,” he said. Solar maximums come around every 11 years, but no one knows why.

“You can have solar flares and aurorae during the solar minimum, but we get more now because the sun’s magnetic field is tangled up and poking through the surface, releasing plasma,” said Nemiroff.

FROM. http://www.sciencedaily.com

Rare Evidence Of Dinosaur Cannibalism: Meat-Eater Tooth Found In Gorgosaurus Jawbone

October 16th, 2012

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University of Alberta researcher Phil Bell has found 70 million year old evidence of dinosaur cannibalism. The jawbone of what appears to be a Gorgosaurus was found in 1996 in southern Alberta. A technician at the Royal Tyrell Museum found something unusual embedded in the jaw. It was the tip of a tooth from another meat-eating dinosaur.

Gorgosaurus

Bell, a paleontology PhD candidate, says discovery of the tooth shows that a fight between two dinosaurs definitely took place. “The wound showed no signs of healing so we know the dinosaur died soon after it was inflicted.” Bell says that leaves two possible storylines. “Either the attacker fought, killed and ate this dinosaur, or the victim was already dead.” Either way, if the attacker and the victim were the same species, Bell has a rare case of dinosaur cannibalism.

Analysis of the wound in the jawbone showed the bite was applied with the same force as a two tonne great white shark. “Sharks are a good analogue for this research,” said Bell. “Their teeth frequently break off in an attack and become lodged in the victim.”

The fossil record shows thatGorgosaurus, a 10-metre long cousin of the bigger, more famous,Tyrannosaurus rex, outnumbered other meat-eating dinosaurs in the area. That leads Bell to believe it’s likely the attacker and the victim were both Gorgosaurus dinosaurs, making this a case of cannibalism.

There is only one proven case of dinosaur cannibalism. That evidence was found in Madagascar in 2007.

Bell and co-author, U of A paleontology professor Phil Currie, published their findings this month in the journal Lethaia.

Cambrian fossil pushes back evolution of complex brains

October 15th, 2012

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The remarkably well-preserved fossil of an extinct arthropod shows that anatomically complex brains evolved earlier than previously thought and have changed little over the course of evolution. According to University of Arizona neurobiologist Nicholas Strausfeld, who co-authored the study describing the specimen, the fossil is the earliest known to show a brain.

The discovery will be published in the Oct. 11 issue of the journal Nature.

Embedded in mudstones deposited during the Cambrian period 520 million years ago in what today is the Yunnan Province in China, the approximately 3-inch-long fossil, which belongs to the species Fuxianhuia protensa, represents an extinct lineage of arthropods combining an advanced brain anatomy with a primitive body plan.

This picture shows a nearly intact fossil of Fuxianhuia protensa. The inset shows the fossilized brain in the head of another specimen. The brain structures are visible as dark outlines. – Specimen photo: Xiaoya Ma; inset: Nicholas Strausfeld

The fossil provides a “missing link” that sheds light on the evolutionary history of arthropods, the taxonomic group that comprises crustaceans, arachnids and insects.

The researchers call their find “a transformative discovery” that could resolve a long-standing debate about how and when complex brains evolved.

“No one expected such an advanced brain would have evolved so early in the history of multicellular animals,” said Strausfeld, a Regents Professor in the UA department of neuroscience.

According to Strausfeld, paleontologists and evolutionary biologists have yet to agree on exactly how arthropods evolved, especially on what the common ancestor looked like that gave rise to insects.

“There has been a very long debate about the origin of insects,” Strausfeld said, adding that until now, scientists have favored one of two scenarios.

Some believe that insects evolved from the an ancestor that gave rise to the malacostracans, a group of crustaceans that include crabs and shrimp, while others point to a lineage of less commonly known crustaceans called branchiopods, which include, for example, brine shrimp.

Because the brain anatomy of branchiopods is much simpler than that of malacostracans, they have been regarded as the more likely ancestors of the arthropod lineage that would give rise to insects.

However, the discovery of a complex brain anatomy in an otherwise primitive organism such as Fuxianhuia makes this scenario unlikely. “The shape [of the fossilized brain] matches that of a comparable sized modern malacostracan,” the authors write in Nature. They argue the fossil supports the hypothesis that branchiopod brains evolved from a previously complex to a more simple architecture instead of the other way around.

This hypothesis arose from neurocladistics, a field pioneered by Strausfeld that attempts to reconstruct the evolutionary relationships among organisms based on the anatomy of their nervous system. Conventional cladistics, on the other hand, usually look to an organism’s overall morphology or molecular data such as DNA sequences.

Strausfeld, who holds appointments in other UA departments including evolutionary biology and entomology, has cataloged about 140 character traits detailing the neural anatomies of almost 40 arthropod groups.

“There have been all sorts of implications why branchiopods shouldn’t be the ancestors of insects,” he said. “Many of us thought the proof in the pudding would be a fossil that would show a malacostracan-like brain in a creature that lived long before the origin of the branchiopods; and bingo! – this is what this is.”

Strausfeld traveled to the Yunnan Key Laboratory for Palaeobiology at Yunnan University in Kunming, China, to join his collaborator, Xiaoya Ma, a postdoctoral fellow at London’s Natural History Museum, in studying the brain anatomies of various fossil specimens. In the institute’s collection, they came across the fossil of Fuxianhuia protensa described in the paper.

“I spent a frenetic five hours at the dissecting microscope, the last hours of my visit there, photographing, photographing, photographing,” he said. “And I realized that this brain actually comprises three successive neuropils in the optic regions, which is a trait of malacostracans, not branchiopods.”

Neuropils are portions of the arthropod brain that serve particular functions, such as collecting and processing input from sensory organs. For example, scent receptors in the antennae are wired to the olfactory neuropils, while the eyes connect to neuropils in the optic lobes.

When Strausfeld traced the fossilized outlines of Fuxianhuia‘s brain, he realized it had three optic neuropils on each side that once were probably connected by nerve fibers in crosswise pattern as occurs in insects and malacostracans. The brain was also composed of three fused segments, whereas in branchiopods only two segments are fused.

“In branchiopods, there are always only two visual neuropils and they are not linked by crossing fibers,” Strausfeld said. “In principle, Fuxianhuia‘s is a very modern brain in an ancient animal.”

The fossil supports the idea that once a basic brain design had evolved, it changed little over time, he explained. Instead, peripheral components such as the eyes, the antennae and other appendages, sensory organs, etc., underwent great diversification and specialized in different tasks but all plugged into the same basic circuitry.

“It is remarkable how constant the ground pattern of the nervous system has remained for probably more than 550 million years,” Strausfeld added. “The basic organization of the computational circuitry that deals, say, with smelling, appears to be the same as the one that deals with vision, or mechanical sensation.”

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