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gncxx King-Size Canary
Great Old One Joined: 25 Aug 2001 Total posts: 13561 Location: Eh? Gender: Male |
 Posted: 22-12-2012 23:22 Post subject: |
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| ramonmercado wrote: | | Kondoru wrote: | Thats just what we need for Xmas...
...A great big sauropod! |
They're plant eating; the worse they'll do is eat your hedge. |
Or trip over you. |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 23-12-2012 02:11 Post subject: |
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Inside the Head of a Dinosaur: Research Reveals New Information On the Evolution of Dinosaur Senses
http://www.sciencedaily.com/releases/2012/12/121219174154.htm
Fossil skull of the Cretaceous therizinosaur Erlikosaurus andrewsi (Credit: Image by Emily Rayfield, University of Bristol)
Dec. 19, 2012 — An international team of scientists, including PhD student Stephan Lautenschlager and Dr Emily Rayfield of the University of Bristol, found that the senses of smell, hearing and balance were well developed in therizinosaurs and might have affected or benefited from an enlarged forebrain. These findings came as a surprise to the researchers as exceptional sensory abilities would be expected from predatory and not necessarily from plant-eating animals.
Therizinosaurs are an unusual group of theropod dinosaurs which lived between 145 and 66 million years ago. Members of this group had evolved into up to 7m (23ft) large animals, with more than 50cm (20in) long, razor-sharp claws on their forelimbs, elongated necks and a coat of primitive, down-like feathers along their bodies. Although closely related to carnivorous dinosaurs such as Tyrannosaurus rex and Velociraptor, and in spite of their bizarre appearance, therizinosaurs were probably peaceful herbivores.
Inspired by this paradox, the international team of palaeontologists decided to take the first close look inside the heads of these enigmatic dinosaurs.
They studied the brain and inner ear anatomy of therizinosaurs using high-resolution CT scanning and 3D computer visualisation to find out more about their sensory and cognitive capabilities and how these had evolved with the transition from meat- to plant-eating.
The focus of the study was the skull of Erlikosaurus andrewsi -- a 3-4m (10-13ft) therizinosaur, which lived more than 90 million years ago in what is now Mongolia.
Lead author, Stephan Lautenschlager of Bristol's School of Earth Sciences said: "Our results suggest that therizinosaurs would have used their well-developed sensory repertoire to their advantage which, for herbivorous animals, must have played an important role in foraging, in the evasion of predators or in social complexity.
"This study sheds a new light on the evolution of dinosaur senses and shows it is more complex than we thought."
Co-author, Professor Lindsay Zanno of the North Carolina Museum of Natural History and the North Carolina State University agrees: "Once you've evolved a good sensory toolkit, it's probably worth hanging on to, whether you're hunting or being hunted."
Fellow author Lawrence Witmer, Chang Professor of Paleontology at the Ohio University Heritage College of Osteopathic Medicine said: "Of course the actual brain tissue is long gone from the fossil skulls but we can use CT scanning to visualize the cavity that the brain once occupied and then generate 3D computer renderings of the olfactory bulbs and other brain parts."
This study has important ramifications for our understanding of how sensory function evolved in different dinosaur groups and whether it was developed as a response to their environment or simply inherited by their ancestors. In particular, in the light of the transition from dinosaurs to birds, these results should prove to be very interesting.
Story Source:
The above story is reprinted from materials provided by University of Bristol.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
Stephan Lautenschlager, Emily J. Rayfield, Perle Altangerel, Lindsay E. Zanno, Lawrence M. Witmer. The Endocranial Anatomy of Therizinosauria and Its Implications for Sensory and Cognitive Function. PLoS ONE, 2012; 7 (12): e52289 DOI: 10.1371/journal.pone.0052289 |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 05-01-2013 14:41 Post subject: |
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| Quote: | Dinosaurs May Have Shaken Their Tail Feathers to Woo Mates
BY NADIA DRAKE01.04.139:30 AM
http://www.wired.com/wiredscience/2013/01/dinosaur-courtship-feathers/
Oviraptor (here, “Ingenia” yanshini) courtship display. Credit: Sydney Mohr, University of Alberta
Visiting Mongolia during the Cretaceous might have revealed a variety of birdlike dinosaurs strutting their stuff and using a spectacular fan of tail feathers to woo potential mates.
The birdlike dinosaurs are oviraptors, so named because their discoverer suspected the first specimen had been fossilized in the act of stealing eggs from a Protoceratops nest. Feathered but flightless, oviraptors had strong, flexible tails tipped with a spray of multicolored feathers, a team of paleontologists reported Jan. 4 in Acta Palaeontologica Polonica.
Studying oviraptor fossils, as well as present-day birds and reptiles, and digitally recreating an oviraptor tail helped the team conclude that, like peacocks and turkeys, oviraptors shook their tail feathers to attract mates.
“You have, I think, a tail that is specifically adapted to flaunt its feathers,” said Scott Persons, study author and doctoral student at the University of Alberta. “Swish it from side to side, show off the tail, strike a sinuous pose and hold it.”
The report is the first to demonstrate the display function for the tail feathers of oviraptors using data from both fossils and living animals, said Xing Xu, a paleontologist at China’s Institute for Vertebrate Paleontology and Paleoanthropology. “In particular, the digital model represents a more rigorous analysis than previous studies concerning the tail feather function,” said Xu, who has also studied oviraptors. The bipedal dinosaurs range from about turkey-size to more than 15 feet long.
Persons began studying oviraptors while working on his master’s thesis. “When I saw the tail of my first oviraptor, it was immediately obvious that something very strange, very different was going on with it,” Persons said. He was looking at the tail of oviraptor Khaan mckennai, unearthed in Mongolia. Oviraptors have short tails, with many vertebrae squished together. The compact joints create a flexible, sinuous appendage, with bony spines that offer attachment points for large, strong muscles.
Additionally, the tips of some oviraptor tails also contain a fused vertebral structure, called a pygostyle. Already, pygostyles had been described as the connecting point for long tail feathers in the well-preserved fossil of oviraptor Similicaudipteryx yixianensis.
When Persons studied more fossils, he found pygostyles in three additional species – good evidence that the feather-hosting structure isn’t an aberration, and is common within the group. Species that didn’t have defined pygostyles still had a set of inflexible vertebrae fused together near the tail tip, Persons said. Today, pygostyles are rare. “You can find pygostyles in one kind of modern day animal, and that’s birds,” Persons said.
Next, the team considered how such a tail might function, and used the tail anatomy of modern day birds and reptiles — such as crocodiles, chickens, lizards, and pigeons — as a guide. Based on both those observations and the bony fossil record, the team digitally reconstructed an oviraptor tail, revealing a musculature dominated by strong, dexterous muscles. “The big muscles in the tail were those associated with swinging and swishing, pulling and tugging the tail up and down, and side to side,” Persons describes.
But what might such a strong, feather-tipped tail be used for? Not flight. And unlike the shorter feathery ‘dinofuzz’ covering the rest of an oviraptor’s body, the tip feathers are long, and unsuited for trapping body heat. “Think of modern day birds that don’t use their tail feathers for flight. What do they use them for?” Persons said. “They use their big tail feather fans for display.”
The study isn’t the first to suggest that, in addition to warmth and flight, dinosaurs may have used feathers to attract mates. “We are now beginning to understand the potential functions of feather types on different parts of the body,” said paleontologist Darla Zelenitsky of the University of Calgary. In October, she described a similar display behavior in another group of dinosaurs, called ornithomimosaurs. Zelenitsky says these results are consistent with hers, which pointed toward forearm feathers as playing a role in display.
Persons is going to continue studying the oviraptor tails, with the goal of adding more fossils to the analysis and determining whether males and females were similarly spangled – and what that might mean for courtship behaviors. “We’re starting to get to the point where we can move away from simple description,” Persons said. “We’ve got enough information in front of us that we can start connecting the dots and thinking about more sophisticated things like behavior.” |
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| Mythopoeika Boring petty conservative
Joined: 18 Sep 2001 Total posts: 9109 Location: Not far from Bedford Gender: Unknown |
| Posted: 05-01-2013 21:08 Post subject: |
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| Quote: | | Dinosaurs May Have Shaken Their Tail Feathers to Woo Mates |
'Woo Mates'? Well, it is Mongolia I suppose.  |
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| rynner2 What a Cad!
Great Old One Joined: 13 Dec 2008 Total posts: 21365 Location: Under the moon Gender: Male |
| Posted: 05-01-2013 21:46 Post subject: |
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Feathers can be fluffy (think of eider down), so does this mean dinos were the original fluffy woo woos?  |
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| Kondoru Unfeathered Biped Joined: 05 Dec 2003 Total posts: 5788 Gender: Unknown |
| Posted: 05-01-2013 23:15 Post subject: |
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| These Dinos are very different to the ones I knew in my childhood...Im beggining to wonder if they are actualy birds.... |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 11-01-2013 12:40 Post subject: |
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| Quote: | Australia's Stampeding Dinosaurs Take a Dip: Largely Tracks of Swimming Rather Than Running Animals
http://www.sciencedaily.com/releases/2013/01/130108190250.htm
Hypothesized reconstruction of the small Lark Quarry trackmaker. (Credit: Illustration by Anthony Romilio, The University of Queensland)
Jan. 8, 2013 — Queensland paleontologists have discovered that the world's only recorded dinosaur stampede is largely made up of the tracks of swimming rather than running animals.
The University of Queensland's (UQ) PhD candidate Anthony Romilio led the study of thousands of small dinosaur tracks at Lark Quarry Conservation Park, central-western Queensland.
Mr Romilio says the 95-98 million-year-old tracks are preserved in thin beds of siltstone and sandstone deposited in a shallow river when the area was part of a vast, forested floodplain.
"Many of the tracks are nothing more than elongated grooves, and probably formed when the claws of swimming dinosaurs scratched the river bottom," Romilio said.
"Some of the more unusual tracks include 'tippy-toe' traces -- this is where fully buoyed dinosaurs made deep, near vertical scratch marks with their toes as they propelled themselves through the water.
"It's difficult to see how tracks such as these could have been made by running or walking animals.
"If that was the case we would expect to see a much flatter impression of the foot preserved in the sediment."
Mr Romilio said that similar looking swim traces made by different sized dinosaurs also indicated fluctuations in the depth of the water.
"The smallest swim traces indicate a minimum water depth of about 14 cm, while much larger ones indicate depths of more than 40 cm," Mr Romilio said.
"Unless the water level fluctuated, it's hard to envisage how the different sized swim traces could have been preserved on the one surface.
"Some of the larger tracks are much more consistent with walking animals, and we suspect these dinosaurs were wading through the shallow water."
Mr Romilio said the swimming dinosaur tracks at Lark Quarry belonged to small, two-legged herbivorous dinosaurs known as ornithopods.
"These were not large dinosaurs," Mr Romilio said.
"Some of the smaller ones were no larger than chickens, while some of the wading animals were as big as emus."
The researchers interpreted the large spacing among many consecutive tracks to indicate that the dinosaurs were moving downstream, perhaps using the current of the river to assist their movements.
Given the likely fluctuations in water depth, the researchers assume the tracks were formed over several days, maybe even weeks.
Previous research had identified two types of small dinosaur tracks at Lark Quarry: long-toed tracks (called Skartopus) and short-toed tracks (called Wintonopus).
The UQ scientists found that just like you 'shouldn't judge a book by its cover', you also 'shouldn't judge a track by its outline'.
"3D profiles of 'Skartopus' tracks reveal that they were made by a short-toed trackmaker dragging its toes through the sediment, thereby elongating the tracks," explained Romilio.
"In this context, they are best interpreted as a just another variant of Wintonopus."
Romilio's supervisor and coauthor of the new paper, Dr Steve Salisbury, added that, "3D analysis of the Lark Quarry tracks has allowed us to greatly refine our understanding of what this site represents.
"It is also allowing us to learn more about how these dinosaurs moved and behaved in different environments," Dr Salisbury said.
For the past 30 years, the tracks at Lark Quarry have be known as the world's only record of a 'dinosaur stampede'.
Previous research by Romilio and Salisbury in 2011 also showed the larger tracks at Lark Quarry were probably made by a herbivorous dinosaur similar to Muttaburrasaurus, and not a large theropod, as had previously been proposed.
"Taken together, these findings strongly suggest Lark Quarry does not represent a 'dinosaur stampede'," Romilio said.
"A better analogy for the site is probably a river crossing."
Dr Salisbury said regardless of how it was interpreted, these findings took nothing away from the importance of the site.
"Lark Quarry is, and will always remain, one of Australia's most important dinosaur tracksites," Dr Salisbury said.
The new study was published in the January 2013 issue of Journal of Vertebrate Paleontology.
More information about dinosaur research at UQ can be found at: http://www.uq.edu.au/dinosaurs/
Story Source:
The above story is reprinted from materials provided by University of Queensland.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
Anthony Romilio, Ryan T. Tucker, Steven W. Salisbury. Reevaluation of the Lark Quarry dinosaur Tracksite (late Albian–Cenomanian Winton Formation, central-western Queensland, Australia): no longer a stampede? Journal of Vertebrate Paleontology, 2013; 33 (1): 102 DOI: 10.1080/02724634.2012.694591 |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 15-01-2013 22:01 Post subject: |
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| Quote: | Dinosaurs: Carmarthenshire was Jurassic 'hotspot'
http://www.bbc.co.uk/news/uk-wales-south-west-wales-21023189
Pantydraco lived in the Early Jurassic period in Wales
Carmarthenshire has been highlighted as a dinosaur hotspot in a new map detailing prehistoric finds.
The county has been identified as an area of interest by the Natural History Museum in relation to the remains of a Pantydraco discovered there.
The herbivore - whose name means 'Pant-y-ffynnon dragon' - lived in the Early Jurassic period in Wales.
The map was compiled from information of dinosaur finds over the last 336 years to accompany a TV programme.
Continue reading the main story
“
Start Quote
This was a small plant-eating dinosaur, which would only have been a couple of metres long”
Dr Paul Barrett
Merit Researcher at the Natural History Museum
Dr Paul Barratt, a merit reseacher in the museum's Department of Palaeontology, said: "I was asked to compile a map of dinosaur finds in the UK and most of them are in England but there are some very important ones in other places too, including Wales where we have some very early dinosaur specimens.
"It's an accident of geology that we don't have many rocks in Wales of the right age to preserve dinosaur fossils, but the ones that do gives us some of these very early dinosaurs which we don't find elsewhere."
Dr Barrett said the best known dinosaur from west Wales was the Pantydraco.
"This was a small plant-eating dinosaur, which would only have been a couple of metres long," he said.
"In fact we've mostly had material of an almost baby of this animal, the best preserved one is probably only about two-and-a-half feet long.
"So these are small bi-pedal plant eaters walking around on their hind legs."
There is also evidence of a couple of carnivores living in the same area, although those finds were confined to teeth.
Dr Barrett added that not much time has been spent searching for dinosaur remains in Wales primarily because a lot of the spots where they are found are were "relatively small and the rock is relatively unproductive".
"So whenever we do find something it's a relatively important find", he said.
"But we also have very nice dinosaur footprints in Wales as well which help fill in some of those blanks.
"They can be found on various foreshores in south Wales, so you can actually go out and see these little three-toed tracks in the rock.
"So little meat eating dinosaurs were running around probably about 200-odd million years ago."
Primeval: New World is broadcast on Watch, on Tuesdays at 21:00 GMT. |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 26-01-2013 01:42 Post subject: |
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Yet another fossil ruffles the feathers of bird flight theory.
| Quote: | New dinosaur fossil challenges bird evolution theory
January 24th, 2013 in Other Sciences / Archaeology & Fossils
Enlarge
This is a reconstruction of Eosinopteryx. Credit: Royal Belgian Institute of Natural Sciences
(Phys.org)—The discovery of a new bird-like dinosaur from the Jurassic period challenges widely accepted theories on the origin of flight.
Co-authored by Dr Gareth Dyke, Senior Lecturer in Vertebrate Palaeontology at the University of Southampton, the paper describes a new feathered dinosaur about 30 cm in length which pre-dates bird-like dinosaurs that birds were long thought to have evolved from.
Over many years, it has become accepted among palaeontologists that birds evolved from a group of dinosaurs called theropods from the Early Cretaceous period of Earth's history, around 120-130 million years ago. Recent discoveries of feathered dinosaurs from the older Middle-Late Jurassic period have reinforced this theory.
The new 'bird-dinosaur' Eosinopteryx described in Nature Communications this week provides additional evidence to this effect.
"This discovery sheds further doubt on the theory that the famous fossil Archaeopteryx – or "first bird" as it is sometimes referred to – was pivotal in the evolution of modern birds," says Dr Dyke, who is based at the National Oceanography Centre, Southampton.
"Our findings suggest that the origin of flight was much more complex than previously thought."
The fossilised remains found in north-eastern China indicate that, while feathered, this was a flightless dinosaur, because of its small wingspan and a bone structure that would have restricted its ability to flap its wings.
The dinosaur also had toes suited to walking along the ground and fewer feathers on its tail and lower legs, which would have made it easier to run.
More information: www.nature.com/ncomms/journal/v4/n1/full/ncomms2389.html
Provided by University of Southampton
"New dinosaur fossil challenges bird evolution theory." January 24th, 2013. http://phys.org/news/2013-01-dinosaur-fossil-bird-evolution-theory.html
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| Kondoru Unfeathered Biped Joined: 05 Dec 2003 Total posts: 5788 Gender: Unknown |
| Posted: 26-01-2013 11:28 Post subject: |
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| Im getting very suspicious about these Dinos.... |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 27-01-2013 14:05 Post subject: |
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| Kondoru wrote: | | Im getting very suspicious about these Dinos.... |
Yeah, when I were a lad we had real dinosaurs, none of these feathered freaks. |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 27-01-2013 14:06 Post subject: |
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| Quote: | More Small Meat-Eating Dinosaurs Than Thought
http://www.sciencedaily.com/releases/2013/01/130123195356.htm
Summary of quantitative morphotypes showing their stratigraphic ages. (Credit: Derek W. Larson, Philip J. Currie. Multivariate Analyses of Small Theropod Dinosaur Teeth and Implications for Paleoecological Turnover through Time. PLoS ONE, 2013; 8 (1): e54329 DOI: 10.1371/journal.pone.0054329)
Jan. 23, 2013 — University of Alberta researchers used fossilized teeth to identify at least 23 species of small meat-eating dinosaurs that roamed western Canada and the United States, 85 to 65 million years ago.
Until now, only seven species of small two-legged meat-eating dinosaurs from the North American west had been identified.
U of A palaeontologist Philip Currie and student Derek Larson examined a massive dataset of fossil teeth that included samples from members of the families to which Velociraptor and Troodon (possibly the brainiest dinosaur) belong.
"Small meat-eating dinosaur skeletons are exceedingly rare in many parts of the world and, if not for their teeth, would be almost completely unknown," said Larson.
The researchers say the huge increase in the number of small meat-eating species to 23, shows that instead of a few species existing for many millions of years, there were actually many small meat-eating species, each existing for shorter periods of time.
"We can identify what meat-eaters lived in what geographic area or geologic age," explained Currie. "And we can do this by identifying just their teeth, which are far more common than skeletons."
Story Source:
The above story is reprinted from materials provided by University of Alberta, via EurekAlert!, a service of AAAS. |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 06-02-2013 15:23 Post subject: |
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| Quote: | Dinosaur Footprints Lifted from NASA's Backyard
Megan Gannon, LiveScience News EditorDate: 04 February 2013 Time: 01:30
http://www.space.com/19622-dinosaur-footprints-nasa-goddard.html
The 12-inch-wide footprint belonged to an armored, tank-like plant-eater.
CREDIT: NASA/GSFC/Rebecca Roth
A chunk of stone bearing dinosaur footprints has been carefully lifted from the grounds of NASA's Goddard Space Flight Center in Greenbelt, Md., scientists report.
The dino tracks, thought to have been left by three separate beasts more than 100 million years ago, were discovered by amateur paleontologist Ray Stanford in August 2012.
The feature that first caught Stanford's eye was a dinner-plate-sized footprint of a nodosaur, a tanklike dinosaur studded with bony protuberances that roamed the area about 110 million years ago during the Cretaceous period (the period from 145 million to 65 million years ago that was the end of the Mesozoic Era). This particular lumbering leaf-eater must have been moving quickly across the prehistoric mud, as its heel did not sink deeply into the ground.
A closer look at the site revealed two more prints. Stephen Godfrey, a paleontology curator at the Calvert Marine Museum, who was contracted to preserve the find, said he suspects one was left by an ornithopod, possibly from the iguanodontid family, which were large vegetarian dinosaurs with birdlike, three-toed feet that walked on its hind legs. Another smaller footprint found superimposed over the nodosaur track is thought to be from a baby nodosaur, perhaps trying to catch up to its parent, according to a statement from NASA. [See Photos of the Dinosaur Footprints at Goddard]
The stretch of ground containing the prints measured about 7 feet long and 3 feet across at its widest point (2 meters by 0.9 meters). After making a silicon-rubber cast of the dino tracks, the team covered the find in plaster-soaked burlap, much like an orthopedic cast, to reinforce the slab and protect it from damage during the big move. Altogether, the stone slab, the protective jacket and surrounding soil weighed about 3,000 pounds (1,360 kilograms), and it was successfully pulled out of the ground last month.
The dinosaur footprints were encased in a field jacket, which is much like a cast that a doctor would place on a broken arm or leg. This field jacket consisted of many layers of burlap soaked in plaster, with metal pipes added to act like splints for additional support.
CREDIT: NASA/GSFC/Rebecca Roth
For now, the prints are being stored at Goddard until further scientific study is possible. The wonder of the discovery has not been lost on space scientists at Goddard, who often find themselves studying starlight as old as the dinosaurs.
"One of the amazing aspects of this find is that some of the starlight now seen in the night sky by astronomers was created in far-distant galaxies when these dinosaurs were walking on mud flats in Cretaceous Maryland where Goddard is now located," Jim Garvin, Goddard's chief scientist, said in a statement. "That starlight (from within the Virgo Supercluster) is only now reaching Earth after having traveled through deep space for 100 million years."
This story was provided by LiveScience, a sister site to SPACE.com. Follow LiveScience on Twitter @livescience. We're also on Facebook & Google+. |
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| Analis Great Old One Joined: 12 Apr 2006 Total posts: 851 Gender: Unknown |
| Posted: 01-03-2013 17:23 Post subject: |
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| ramonmercado wrote: | | Kondoru wrote: | | Im getting very suspicious about these Dinos.... |
Yeah, when I were a lad we had real dinosaurs, none of these feathered freaks. |
Well, I like all these proto-birds or primitive avialians/birds. When Jurassic Park was released, I was a bit disappointed that they had been too timorous to show feathered raptors.
On the other hand, I liked the description of the likes of Struthiomimus, Gallimimus and Ornithomimus as looking like ostriches without feathers... :
http://www.sciencedaily.com/releases/2012/10/121025150357.htm
| Quote: | Fossils of First Feathered Dinosaurs from North America Discovered: Clues On Early Wing Uses
Oct. 25, 2012 — 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 Science reveals 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.
"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 of Ornithomimus, 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. |
Interesting, because the article seems to describe the presence of waned feathers on their arms. Which would make of ornithomimids the most remote relative of birds with waned feathers known until now. |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 04-03-2013 02:22 Post subject: |
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| Quote: | http://www.sciencedaily.com/releases/2013/02/130228171504.htm
New Dinosaur Species: First Fossil Evidence Shows Small Crocs Fed On Baby Dinosaurs
Clint Boyd, Ph.D., of the South Dakota School of Mines & Technology, points to a crocodyliform tooth embedded in the femur of a young dinosaur. (Credit: South Dakota School of Mines & Technology)
Feb. 28, 2013 — A South Dakota School of Mines & Technology assistant professor and his team have discovered a new species of herbivorous dinosaur and today published the first fossil evidence of prehistoric crocodyliforms feeding on small dinosaurs.
Research by Clint Boyd, Ph.D., provides the first definitive evidence that plant-eating baby ornithopod dinosaurs were a food of choice for the crocodyliform, a now extinct relative of the crocodile family. While conducting their research, the team also discovered that this dinosaur prey was a previously unrecognized species of a small ornithopod dinosaur, which has yet to be named.
The evidence found in what is now known as the Grand Staircase Escalante-National Monument in southern Utah dates back to the late Cretaceous period, toward the end of the age of dinosaurs, and was published today in the online journal PLOS ONE. The complete research findings of Boyd and Stephanie K. Drumheller, of the University of Iowa and the University of Tennessee, and Terry A. Gates, of North Carolina State University and the Natural History Museum of Utah, can be accessed online (see journal reference below).
A large number of mostly tiny bits of dinosaur bones were recovered in groups at four locations within the Utah park -- which paleontologists and geologists know as the Upper Cretaceous (Campanian) Kaiparowits Formation -- leading paleontologists to believe that crocodyliforms had fed on baby dinosaurs 1-2 meters in total length.
Evidence shows bite marks on bone joints, as well as breakthrough proof of a crocodyliform tooth still embedded in a dinosaur femur.
The findings are significant because historically dinosaurs have been depicted as the dominant species. "The traditional ideas you see in popular literature are that when little baby dinosaurs are either coming out of a nesting grounds or out somewhere on their own, they are normally having to worry about the theropod dinosaurs, the things like raptors or, on bigger scales, the T. rex. So this kind of adds a new dimension," Boyd said. "You had your dominant riverine carnivores, the crocodyliforms, attacking these herbivores as well, so they kind of had it coming from all sides."
Based on teeth marks left on bones and the large amounts of fragments left behind, it is believed the crocodyliforms were also diminutive in size, perhaps no more than 2 meters long. A larger species of crocodyliform would have been more likely to gulp down its prey without leaving behind traces of "busted up" bone fragments.
Until now, paleontologists had direct evidence only of "very large crocodyliforms" interacting with "very large dinosaurs."
"It's not often that you get events from the fossil record that are action-related," Boyd explained. "While you generally assume there was probably a lot more interaction going on, we didn't have any of that preserved in the fossil record yet. This is the first time that we have definitive evidence that you had this kind of partitioning, of your smaller crocodyliforms attacking the smaller herbivorous dinosaurs," he said, adding that this is only the second published instance of a crocodyliform tooth embedded in any prey animal in the fossil record.
"A lot of times you find material in close association or you can find some feeding marks or traces on the outside of the bone and you can hypothesize that maybe it was a certain animal doing this, but this was only the second time we have really good definitive evidence of a crocodyliform feeding on a prey animal and in this case an ornithischian dinosaur," Boyd said.
The high concentrations of tiny dinosaur bones led researchers to conclude a type of selection occurred, that crocodyliforms were preferentially feeding on these miniature dinosaurs. "Maybe it was closer to a nesting ground where baby dinosaurs would have been more abundant, and so the smaller crocodyliforms were hanging out there getting a lunch," Boyd added.
"When we started looking at all the other bones, we starting finding marks that are known to be diagnostic for crocodyliform feeding traces, so all that evidence coming together suddenly started to make sense as to why we were not finding good complete specimens of these little ornithischian dinosaurs," Boyd explained. "Most of the bites marks are concentrated around the joints, which is where the crocodyliform would tend to bite, and then, when they do their pulling or the death roll that they tend to do, the ends of the bones tend to snap off more often than not in those actions. That's why we were finding these fragmentary bones."
In the process of their research, the team discovered through diagnostic cranial material that these baby prey are a new, as yet-to-be-named dinosaur species. Details on this new species will soon be published in another paper.
Story Source:
The above story is reprinted from materials provided by South Dakota School of Mines and Technology.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
Clint A. Boyd, Stephanie K. Drumheller, Terry A. Gates. Crocodyliform Feeding Traces on Juvenile Ornithischian Dinosaurs from the Upper Cretaceous (Campanian) Kaiparowits Formation, Utah. PLoS ONE, 2013; 8 (2): e57605 DOI: 10.1371/journal.pone.0057605 |
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