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Dinosaurs: New Findings & Theories

Kondoru

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Hurrah! This is what we want!

Not dinky dino birds, cute and pettable as they may be.
 

Mythopoeika

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Yes, that's a proper dinosaur - immense. :shock:
 

ramonmercado

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Dinosaurs 'neither warm nor cold blooded'

Dinosaurs fit in an intermediate class between warm and cold blooded animals, a study in the journal Science claims.

Scientists compared the growth rates of hundreds of living and extinct species, using growth rings and bone size to calculate the rates for dinosaurs.

They linked growth rate to metabolic rate, the measure of energy use that divides warm and cold blooded animals.

The study suggests that the dinosaurs fall into a middle category, in a fresh contribution to an enduring debate.

Warm blooded animals, like mammals and birds, need a lot of fuel and use that energy to their advantage, including faster movement and boosted brain power. In burning all that food they also maintain a high, stable body temperature.

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They've taken real, empirical data from living animals and come up with a model”

Dr Paul Barrett
Natural History Museum
Cold blooded animals are more economical, but lack those advantages.

"If I were eating sandwiches all day... I might have to eat five," explained John Grady, the study's first author and a PhD student at the University of New Mexico. "But a reptile [my size] can eat maybe a couple of sandwiches in a whole week."

Scientists define these different strategies as "endothermy" (endo for inside; therm for heat) and "ectothermy".

The question of which biological system underpinned the lumbering success of the dinosaurs is arguably "the last big one", Mr Grady told the BBC - following other big debates over their extinction and their relationship to birds.

His paper proposes that dinosaurs may have used a not-too-hot, not-too-cold approach: "mesothermy".

iguanadon metatarsal
The size and annual growth rings of fossilised bones can be used to calculate how fast dinosaurs grew
The evidence for this idea comes from a big survey of the growth rates in 381 different species, including 21 dinosaurs. Because bones show growth rings much like trees, the size of fossilised dinosaur bones at different ages allows palaeontologists to calculate how fast they put on weight over a lifetime.

Information from the hundreds of living species showed that metabolic rate - the sandwich factor - is higher in animals that grow faster.

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It reminds us that living organisms don't always show the only or best adaptations; dinosaurs did something else”

Prof Mike Benton
University of Bristol
"If you double your metabolic rate, you roughly double your growth rate," Mr Grady said.

So he and his colleagues took growth rate as an indicator of metabolism, and found that dinosaurs occupied a middle ground, somewhere in between modern reptiles and mammals.

Their results also place several living animals with unusual energy habits into the proposed mesothermic category.

Tuna, some sharks, and the leatherback turtle, for example, generate more heat than other fish and reptiles, while the echidna, Australia's spiny egg-laying mammal, shows an un-mammalian inability to maintain a constant body temperature.

'Problematic' or 'unsurprising'?
The idea that dinosaurs fit poorly into existing categories is not entirely new. In a study published in February, researchers from the University of Mainz placed dinosaurs in the middle of their own growth-rate survey.

"Personally I don't find the result very surprising," commented Dr Paul Barrett from the Natural History Museum in London. But he was impressed that the new paper had convincingly added metabolic rates to the picture. ...
http://www.bbc.com/news/science-environment-27794723
 

ramonmercado

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Dinosaur skeleton as old as 120mn years discovered in Siberia

A well-preserved dinosaur’s skeleton, presumably between 100 and 120 million years old, has been dug up in Russia’s Kemerovo Region in Western Siberia. Paleontologists believe they have found Psittacosaurus sibiricus.

Discovered at a depth of some 2.5 meters below the surface, the fossil has been brought to the surface with a huge chunk of soil as a monolith piece weighting about 500kg. The work to extract the skeleton may take months.

The finding is a huge success for a group of Russian paleontologists, who started the expedition in the extensively-excavated area around the village of Shestakovo on May 24.

While the area is known for paleontological discoveries, it is the first time such a well-preserved fossil has been found.

“Dinosaur skeletons can be found quite often in particular parts of the world - for example in China, or Mongolia. But for Siberia this is a unique discovery,” Aleksey Lopatin from the Paleontological Institute of the Russian Academy of Sciences, told the Vechernyaya Moskva newspaper. “Only a few Psittacosaurus skeletons have been found before. It is quite possible that for this place this is not a new species of this dinosaur. Back in those times Siberia had its own kind of Psittacosaurus, different than in China or Mongolia.”

Dinosaurs of the Psittacosaurus family lived in Asia about 100-130 million years ago. They were bipedal herbivores about the size of a gazelle with a powerful ‘beak’ on their upper jaw.

The rare finds will go on display in the regional museum, local authorities said in a statement.

http://rt.com/news/168000-siberia-dinos ... -kemerovo/
 

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New fossil shows Archaeopteryx sported 'feathered trousers'

Details of the plumage of the 11th specimen of Archaeopteryx. Credit: Nature 511, 79–82 (03 July 2014) doi:10.1038/nature13467

The origin of feathers and the origin of flight have been a contentious chicken-and-egg issue in the scientific world for decades. Did feathers develop as a flight mechanism - or were they first used for other purposes?
Now, the discovery of an Archaeopteryx skeleton with feathered "trousers" bolsters the idea that these feathers weren't for flying and initially may have been used as impressive displays. The findings in the journal Nature shed light on the complex evolution of feathered flight.

Archaeopteryx, which lived in the late Jurassic period roughly 150 million years ago, is considered a transitional species, sharing many characteristics of both dinosaurs and modern birds. The handful of skeletons and their fossilized feather impressions - sometimes poorly preserved - have led to various ideas about how this dinosaur lived. Some say its feathers were used for flight, others argue that their plumage was primarily for showing off to potential mates. Some saw feathers on the animals' hind limbs and proposed that Archaeopteryx was a four-winged glider, using both pairs of limbs to soar through the air.

Now, a team of German scientists have examined a remarkably well preserved specimen and found different kinds of feathers covering different parts of its body. It boasts long, 4- to 4.5-centimeter feathers on its hind limb, which are more than half the length of the tibiotarsus leg bone. But in a blow to the four-winged theory, the feathers were symmetrical on either side of their stems, making them less useful for flight. Aerodynamic feathers used for flight are asymmetrical, with one side narrower and the other wider (looking a little like wings themselves). ...

http://phys.org/print323538982.html
 

PeteByrdie

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Fossil of 'largest flying bird' identified

The fossilised remains of the largest flying bird ever found have been identified by scientists.

This creature would have looked like a seagull on steroids - its wingspan was between 6.1 and 7.4m (20-24ft).

The find is published in the Proceedings of the National Academy of Sciences.

The 25m-year-old fossil was unearthed 30 years ago in South Carolina, but it has taken until now to identify that this is a new species.

Daniel Ksepka, curator of science at the Bruce Museum in Connecticut, said: "This fossil is remarkable both for the size, which we could only speculate on before the discovery, and for the preservation.

"The skull in particular is exquisite.

"And given the delicate nature of the bones... it is remarkable that the specimen made it to the bottom of the sea, became buried without being destroyed by scavengers, fossilised, and then was discovered before it was eroded or bulldozed away."

The researchers believe this huge bird surpasses the previous recorder-holder, Argentavis magnificens - a condor-like bird from South America with an estimated wingspan of 5.7-6.1m (19-20ft) that lived about six million years ago.

Scientists have called the new giant Pelagornis sandersi. They believe it would have been twice the size of the wandering albatross, the largest living bird.

Like the albatross, it was a seabird, spending most of its time swooping above the ocean, preying on fish and squid.

Despite its scale, it would have been an elegant flier.

While theoretical models suggest that it would be tricky for a bird of this size to stay airborne by flapping its wings, researchers believe it used air currents to soar above the ocean.

Its long, slender wings and light, hollow bones would have made it a powerful glider.

"It would have been fast and very efficient," said Dr Ksepka.

"Computer models suggest that it had high lift-to-drag ratios, which would allow it to glide for a very long distance for every unit of altitude it could attain.

"It could likely glide at speeds over 10m per second - faster than the human world record for the 100m dash."

On land, though, the seabird was probably far less graceful.

"The long wings would have been cumbersome and it would have probably spent as little time as possible walking around," Dr Ksepka explained.

Taking off would also have been an ungainly affair.

Computer models reveal that the bird could not have taken off by simply standing still and flapping its wings.

Instead, scientists think P. sandersi might have had to waddle downhill and hope to catch a gust of air.

Huge birds like this were once common, but they vanished about three million years ago.

Scientists do not yet understand why these giants of the skies died out.
http://www.bbc.co.uk/news/science-environment-28164063

It's all quite enough to give an old pirate albatross wingspan envy.
 

Analis

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More info on the new « feathered » or hairy basal ornitischian (which appears not to have had complex feathers, but the same kind of bristly hair already known on small ornitischians) :

http://www.dinochecker.com/dinosaurs/KULINDAPTERYX

Categories: Ornithopoda • Herbivore • Russia • Ukureisk • Late Jurassic

[Ornithopoda] KULINDAPTERYX
[no image available]
Pronunciation: koo-lin-dap-tuh-rix
Meaning: Kulinda wing
Author: Alifanov and Saveliev (2014)
Previous names: None known
First discovery: Transbaikal, Siberia
Roar factor: 1/10

Kulindapteryx ukureica
Having waited what seemed like an eternity for the official unveiling of a rumoured-to-be-feathered ornithopod from Kulinda that was initially nicknamed "Kulindosaurus", and later referred to as "Kulindodromeus", that was supposed to be described by Pascal Godefroit, Alifanov and Saveliev took everyone by surprise in 2014 when they officially named a "feathered" ornithopod from Kulinda Kulindapteryx. Fossilized in volcanic ash, patches of skin show that its lower legs, feet and tail underside were scaled but the rest of it was covered with "feather-like structures" which would place the evolution of feathers closer to the base of the dinosaurian family tree, rather than in the theropod clade which is where evidence has always pointed. However, despite the "pteryx" of its official name meaning "wing", the "feathers" seem to be nothing more than bristly hairs, which is old news as such structures have already been found on other ornithischians such as Tianyulong and Psittacosaurus.

Because what should've been the official presentation of "Kulindodromeus" at SVP in 2013 was pulled at the last minute due to health issues we weren't sure if Kulindapteryx was based on the same Kulinda remains or not. Perhaps it was an entirely different species, of the same family, with similar features, from the exact same area, but our suspicious minds kept telling us that said delay opened a window of opportunity for taxonomic claim jumpers, and we feared that Godefroit had been well and truly "scooped". In fact, it was far worse than that.

A note from Godefroit:
"Please forget about those names (Kulindapteryx ukureica and Daurosaurus olovus). These are based on specimens that Alifanov stole in Chita and that are illegally housed in PIN in Moscow but belonging in fact to the Institute of Natural Resources Ecology and Cryology (Chita). Moreover there is a single taxon. And it is not a hypsilophont but a basal ornithischian. This paper is a true paleontological scandal! The official paper implying the original discoverers of the specimens... and based on the legal INREC material in Chita... will be published in July in one of the highest-ranked scientific journals!"

Discovery
The remains of Kulindapteryx were discovered in the Ukureisk Formation (formerly the Kulinda Formation), Olovsk (Nerchinsk) Group, Kulinda Valley, 3 km west of Novoil'insk Village, Chernyshevskii District, Transbaikal region, Russia, in 2011 by a joint expedition of the Russian Academy of Sciences; the Siberian branch of the Institute of Natural Resources, Ecology and Cryology (INREC) and the Borissiak paleontological institute (PIN).
(Kulinda runner from Ukureisk)

Etymology
Kulindapteryx is derived from "Kulinda" (for the area in which it was discovered) and the Latin "pteryx" (wing).
The species epithet, ukureica, is derived from "Ukureisk" (for the Ukureisk Formation).

References
• V.R. Alifanov & S.V. Saveliev (2014) "Two new ornithischian dinosaurs (Hypsilophodontia, Ornithopoda) from the Late Jurassic of Russia".

Estimations
Timeline:
Era: Mesozoic
Period: Late Jurassic
Timespan: 151-145? million years ago
Age: Tithonian?
Vital Stats:
Est. Max. Length: ?
Est. Max. Height: ?
Est. Max. Weight: ?
Diet: Herbivorous

Family Tree:
Dinosauria
Ornithischia
Neornithischia
Jeholosauridae
Kulindapteryx
ukureica
 

Kondoru

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And of course, our giant seagull is still a dino.
 

ramonmercado

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This should result in a good debate, scales and feathers will fly among researchers..

Researchers declassify dinosaurs as being the great-great-grandparents of birds

A skeletal reconstruction of Scansoriopteryx with outlines to indicate the extent of the feathers. Credit: Stephen A. Czerkas

The re-examination of a sparrow-sized fossil from China challenges the commonly held belief that birds evolved from ground-dwelling theropod dinosaurs that gained the ability to fly. The birdlike fossil is actually not a dinosaur, as previously thought, but much rather the remains of a tiny tree-climbing animal that could glide, say American researchers Stephen Czerkas of the Dinosaur Museum in Blanding, Utah, and Alan Feduccia of the University of North Carolina. The study appears in Springer's Journal of Ornithology.

The fossil of the Scansoriopteryx (which means "climbing wing") was found in Inner Mongolia, and is part of an ongoing cooperative study with the Chinese Academy of Geological Sciences. It was previously classified as a coelurosaurian theropod dinosaur, from which many experts believe flying dinosaurs and later birds evolved. The research duo used advanced 3D microscopy, high resolution photography and low angle lighting to reveal structures not clearly visible before. These techniques made it possible to interpret the natural contours of the bones. Many ambiguous aspects of the fossil's pelvis, forelimbs, hind limbs, and tail were confirmed, while it was discovered that it had elongated tendons along its tail vertebrae similar to Velociraptor.

Czerkas and Feduccia say that Scansoriopteryx unequivocally lacks the fundamental structural skeletal features to classify it as a dinosaur. They also believe that dinosaurs are not the primitive ancestors of birds. The Scansoriopteryx should rather be seen as an early bird whose ancestors are to be found among tree-climbing archosaurs that lived in a time well before dinosaurs. ...

http://phys.org/news/2014-07-declassify ... birds.html
 

ramonmercado

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Preserved tracks in Alaska park suggest duck-billed dinosaurs lived in Arctic year-round

Figure 3 from Fiorillo et al. A–C: Size ranges of tracks found at Denali National Park, Alaska, tracksite. D: Adult hadrosaurid track with skin impressions. Scale bar for C1 is 5 cm. Credit: Geological Society of America

(Phys.org) —A trio of researchers has published the results of a study of dinosaur tracks found in Alaska's Denali National Park in 2007. Anthony Fiorillo, Stephen Hasiotis and Yoshitsugu Kobayashi, of the Perot Museum, the University of Kansas and Hokkaido Museum respectively, report, in an article published in the journal Geology, on their analysis of 70 million year old hadrosaur footprints and what they revealed about the lifestyle of the dinosaurs.

Hadrosaurs, more commonly referred to as duck-billed dinosaurs (because of their unique crest) lived approximately 69 to 72 million years ago—there were several species living on several different continents. In this study of the preserved footprints found in Alaska, the researchers found evidence of both pack and family behavior.

The footprints were found on a piece of land not much bigger than a soccer field—scientists working there found thousands of preserved tracks from several types of animals and insects—all living during the during the Late Cretaceous. In this study, the emphasis was on the hadrosaurs.

The team found footprint size ranged from 8 to 64 centimeters, which they said could be attributed to dinosaurs of four different groups: adults, near-adults, juveniles, and the very young. The majority of the tracks were made by adults or those close to being full grown—84 percent. Very young members made up 13 percent of the tracks while juveniles made up just 3 percent of the total. Because the tracks appear to have been made near in time to one another, the researchers suggest they offer evidence that the dinosaurs lived as family units within a herd. The small number of juvenile tracks, they add, likely means that the dinosaurs had a very short juvenile period—they probably grew pretty fast because at that stage they would have been very vulnerable to predators. Also, it appears unlikely the small dinosaurs would have been able to migrate, thus the footprints offer evidence that the dinosaurs lived in the Arctic year-round. ...

http://phys.org/news/2014-07-tracks-ala ... rctic.html
 

Kondoru

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Feducca, though he is the authority on prehistoric aves, is also notorious for being anti dino.

he has some good arguments too, though most from before this current clutch of Chinese tobi-tatsu.

(Yes, I know thats not Mandarin, its a Japanese monster, the dragonbird, but it does for this)
 

Analis

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Scansoriopteryx is usually considered as a somewhat abberant coelurosaur, notably relating to the basin. Not enough to ressurect old theories, that would be contradicted by massive amounts of new data (especially as its unusual features are not shared by early avialans). Feduccia is known for a number of mistakes and campaigns based on dubious arguments. His anti-dinosaur stance could be described as obsessional, he has gone as far as declaring that maniraptorans were not dinosaurs. For years he had relied on a number of difficult-to-interpret studies on the development of the hands of birds, asserting from ambiguous observations that the first digit of a bird was not a thumb, despite warnings from embryologists. Until a developmental genetics study proved that a bird's thumb was, indeed, a thumb, who would have guessed ?

Czerkas is a good artist, but the man never stroke me as a great scientist. He seems too to have a tiny grasp on basic logic when it comes to birds-theropods relationships. He is also prone to promote slapdash-work, theories studied in a rush that fail to catch the attention of other paleontologists.
 

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Four-winged dinosaur is 'biggest ever'

Changyuraptor used its remarkably long tail feathers to smooth its landing

A new four-winged dinosaur has been discovered, with exceptionally long feathers on its tail and "hindwings".

Changyuraptor yangi was a gliding predator which lived in the Cretaceous period in what is now Liaoning, China.

Its remarkable tail feathers - measuring up to 30cm - are the longest in any non-avian dinosaur.
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The tail would have acted as a pitch control structure reducing descent speed... which could be critical to a safe landing or precise attack on prey”

Lizhuo Han
Bohai University, China
This unusual plumage helped the creature to slow down during flight and land safely, say scientists writing in Nature Communications.

C. yangi is a new species of microraptorine, a group related to early avians.

These ancient creatures offer clues to the origin of flight - and the transition from feathered dinosaurs to birds.

Palaeontologists once thought that four-winged gliders were a stepping stone in the path to two-winged flight.

But recent fossil discoveries suggest that microraptorines were an evolutionary side-branch.

Flight probably evolved many times in different feathered species - not only the lineage which ultimately became birds. ...

http://www.bbc.com/news/science-environment-28295571
 

ramonmercado

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Hmmm, pillows filled with dino-down, might make for a safer Jurassic Park to recreate this lot.

Feathersaurus: plant-eating dinos had plumage too

19:00 24 July 2014 by Andy Coghlan

Many dinosaurs may have been covered in elaborate feathers similar to those of modern-day birds, according to a study of new fossils. The finding raises the possibility that the very earliest dinosaurs had feathers, and that such plumage was much more common than thought.

The prevailing theory is that the only feathery dinosaurs were two-legged flesh-eaters called theropods, such as Velociraptor. Ultimately, some theropods evolved into today's birds via intermediates such as Archaeopteryx.

Theropods belong to one of the two major dinosaur groups, the saurischians. Now new fossils suggest that the other major group, the ornithischians, also bore feathers. Ornithischians were plant-eaters and include famous dinosaurs such as Triceratops, Iguanodon and Stegosaurus.

Recently, ornithischians have been found with what appear to be bristly feathers. But these putative feathers were very simple compared with those of theropods and birds. The latest fossil finds are far more elaborate.

Feathers, feathers everywhere

Pascal Godefroit of the Royal Belgian Institute of Natural Sciences in Brussels and his colleagues analysed six partial skulls and several hundred other fossils of limb and other bones from two sites in south-east Siberia. They all belong to a new ornithischian called Kulindadromeus zabaikalicus, which lived 160 million years ago.

K. zabaikalicus was about 1.5 metres long. It was bipedal, with a small, coot-like head and a pointed tail. It foraged for plants in swamps, using its front limbs to manipulate its food. ...

http://www.newscientist.com/article/dn2 ... 9F28fldVsk
 

ramonmercado

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Dinosaurs 'shrank' regularly to become birds
By Zoe Gough
Reporter, BBC Nature

Body trait analysis shows the miniaturisation of theropods started about 50 million years before Archaeopteryx, the earliest bird, lived.

Huge meat-eating, land-living dinosaurs evolved into birds by constantly shrinking for over 50 million years, scientists have revealed.

Theropods shrunk 12 times from 163kg (25st 9lb) to 0.8kg (1.8lb), before becoming modern birds.

The researchers found theropods were the only dinosaurs to get continuously smaller.

Their skeletons also changed four times faster than other dinosaurs, helping them to survive.

Results from the study are reported in the journal Science.

Previous work has shown that theropod dinosaurs, the dinosaur group which included Tyrannosaurus rex and Velociraptor and gave rise to modern birds, must have decreased in size at some point in their evolution into small, agile flyers.

But size changes frequently occurred in dinosaur evolution, so the research team members, led by Mike Lee, from the University of Adelaide, Australia, wanted to find out if the dramatic size reduction associated with the origin of birds was unique.

They also wanted to measure the rate of evolution in dinosaurs using a large data set.

The authors used sophisticated analytical tools - developed by molecular biologists trying to understand virus evolution - to study more than 1,500 dinosaur body traits coded from 120 well-documented species of theropod and early birds.

From this analysis they produced a detailed family tree mapping out the transformation of theropods to their bird descendants.

It traces evolving adaptations and changing body size over time and across dinosaur branches.

They found that the dinosaur group directly related to birds shrank rapidly from about 200 million years ago.

It showed a decrease in body mass of 162.2kg (25st 7lb) from the largest average body size to Archaeopteryx, the earliest known bird.

These bird ancestors also evolved new adaptations, including feathers, wishbones and wings, four times faster than other dinosaurs.

A broad-billed hummingbird (Cynanthus latirostris) in front of a tooth of a massive dinosaurian.
Shrinking and new bird-like traits jointly influenced the transition of dinosaurs to birds, researchers say.
The researchers concluded that the evolution of the branch of dinosaurs leading to birds was more innovative than other dinosaur lineages.

The authors say this sustained shrinking and accelerated evolution of smaller and smaller body size allowed the ancestors of birds to develop traits which helped them to cope much better than their less evolved dinosaur relatives. ...

http://www.bbc.co.uk/nature/28563682
 

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First Venezuelan dino provides clues to dinosaur evolution

Venezuela has its first dinosaur! The 200-million-year-old creature, pictured here in an artist’s reconstruction, has been named Laquintasaura venezuelae, after the La Quinta Formation of the Venezuelan Andes mountains in which it was found. It was the size of a small dog and most likely a plant eater, but the curved tips of some of its teeth suggest it might also have chomped on insects. The research team, which reports the discovery online today in the Proceedings of the Royal Society B, says that the new dino is important for several reasons.

First, it is an early ornithischian dinosaur, a group that includes later horned critters such as Triceratops and Stegosaurus, and which split from the saurischian dinosaurs (which include behemoths as diverse as the long-necked Diplodocus and the meat-eating Tyrannosaurus rex) soon after dinosaurs arose about 230 million years ago. Very few early ornithischians are known, so the new Venezuelan species may provide important clues about early dino evolution.

Second, the sighting of an early, well-dated ornithischian so near the equator (which at that time ran right through what is today Venezuela) expands the range of this dino group and contradicts earlier hypotheses that ornithischians could not have lived in such warm, tropical climates.

And third, at least four Laquintasaura individuals were found together, which the team interprets as evidence that ornithischian dinos lived in “herds,” a kind of social behavior not previously seen so early in the fossil record.

http://news.sciencemag.org/evolution/20 ... -evolution
 

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New evidence raises questions about when dinosaurs evolved in North America

Collage: Jose-Luis Olivares/MIT (original background photograph courtesy of Malka Machlus from Lamont-Doherty Earth Observatory of Columbia University)

The Jurassic and Cretaceous periods were the golden age of dinosaurs, during which the prehistoric giants roamed the Earth for nearly 135 million years. Paleontologists have unearthed numerous fossils from these periods, suggesting that dinosaurs were abundant throughout the world. But where and when dinosaurs first came into existence has been difficult to ascertain.

Fossils discovered in Argentina suggest that the first dinosaurs may have appeared in South America during the Late Triassic, about 230 million years ago—a period when today's continents were fused in a single landmass called Pangaea. Previously discovered fossils in North America have prompted speculation that dinosaurs didn't appear there until about 212 million years ago—significantly later than in South America. Scientists have devised multiple theories to explain dinosaurs' delayed appearance in North America, citing environmental factors or a vast desert barrier.

But scientists at MIT now have a bone to pick with such theories: They precisely dated the rocks in which the earliest dinosaur fossils were discovered in the southwestern United States, and found that dinosaurs appeared there as early as 223 million years ago. What's more, they demonstrated that these earliest dinosaurs coexisted with close nondinosaur relatives, as well as significantly more evolved dinosaurs, for more than 12 million years. To add to the mystery, they identified a 16-million-year gap, older than the dinosaur-bearing rocks, where there is either no trace of any vertebrates, including dinosaurs, in the rock record, or the corresponding rocks have eroded.

"Right below that horizon where we find the earliest dinosaurs, there is a long gap in the fossil and rock records across the sedimentary basin," says Jahan Ramezani, a research scientist in MIT's Department of Earth, Atmospheric and Planetary Sciences. "If the record is not there, it doesn't mean the dinosaurs didn't exist. It means that either no fossils were preserved, or we haven't found them. That tells us the theory that dinosaurs simply started in South America and spread all over the world has no firm basis." ...

This story is republished courtesy of MIT News (web.mit.edu/newsoffice/), a popular site that covers news about MIT research, innovation and teaching.

http://phys.org/news/2014-08-evidence-d ... erica.html
 

Analis

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ramonmercado said:
Hmmm, pillows filled with dino-down, might make for a safer Jurassic Park to recreate this lot.
At least, Transformers 4 shows a psittacosaur with bristles on the upper side of the tail...
 

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New dinosaur 'heavier than a Boeing 737' discovered in Argentina
Dreadnoughtus schrani was the size of seven Tyrannosaurus Rex and would have been utterly untroubled by predators, say experts

An enormous species of dinosaur, which weighed more than a Boeing 737, has been discovered by scientists who claim the beast was so large it would have “feared nothing”.

Named Dreadnoughtus schrani, after the fortified dreadnought battleships of the early 20th century, the herbivore would have done little other than eat in order to support its vast frame.

Measurements of its fossilised bones suggest that the creature measured 85ft (26m) in length and weighed about 65 tonnes – equal to more than seven Tyrannosaurus Rex, four diplodocus or a dozen African elephants.

The remains unearthed in Argentina represent by far the most complete skeleton ever recovered of a supermassive herbivore from a group known as titanosaurs.

Although partial skeletons of potentially larger cousins have previously been found, the find makes Dreadnoughtus the largest land animal for which a body size can be accurately estimated.

“It is by far the best example we have of any of the most giant creatures to ever walk the planet,” said Dr Kenneth Lacorvara of Drexel University in Philadelphia, who made the discovery.

Examination of the 77-million-year-old specimen suggested it may not even have been fully grown at the time it died, he reported in the Scientific Reports journal.

The haul of bones unearthed in southern Patagonia between 2005 and 2009 included most of the vertebrae from the 30ft tail, a neck vertebra measuring more than a yard across, and a thigh bone which at 6ft in length is taller than the average man. ...

- See more at: http://www.independent.ie/world-news/am ... 56xu7.dpuf
 

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Was the gravity lighter in those days? How could this creature even move?
 

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AFAIK, creatures this size would have spent much of their time wading about in lakes and rivers, seldom going on to land. Their necks would be long so they could graze the trees on the shore.
 

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Mythopoeika said:
AFAIK, creatures this size would have spent much of their time wading about in lakes and rivers, seldom going on to land. Their necks would be long so they could graze the trees on the shore.
That idea seems to have fallen out of favour over the years. Perhaps this discovery will revive it, for this species at least.
 

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PeteByrdie said:
Mythopoeika said:
AFAIK, creatures this size would have spent much of their time wading about in lakes and rivers, seldom going on to land. Their necks would be long so they could graze the trees on the shore.
That idea seems to have fallen out of favour over the years. Perhaps this discovery will revive it, for this species at least.
Yeah, I'd heard that too - but I have no idea why scientists would turn their backs on that idea. To me, it's the most logical/most likely explanation of how such huge creatures could survive. It's also a good explanation of why so many such creatures ended up being swept away by ancient floods.
 

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Another big one.

Spinosaurus was largest predator to stalk land or sea

A terrifying cross between Tyrannosaurus rex, a crocodile, and a whale was the largest predator ever to walk the Earth — or swim in its rivers.

Spinosaurus is the first dinosaur known to have been adapted to an aquatic lifestyle.

Weighing 20 tonnes and measuring 15m long, it was 2.7m longer than the largest T. rex specimen known.

It also had jaws filled with vicious slanted teeth and a snout like that of a massive crocodile, while its short muscular hind legs were equipped for paddling and resembled those seen in early limbed whales.

The creature also had powerful forelimbs with curved, blade-like claws ideal for hooking into or slicing prey.

While other dinosaurs such as T. rex hunted on land, Spinosaurus pursued sharks and other large fish in the deep river system it inhabited.

Plesiosaurs, a family of giant marine reptiles, lived alongside Spinosaurus 97m years ago, but were not dinosaurs.

Until now, all dinosaurs were previously thought to have been confined to the land.

Lead researcher Nizar Ibrahim from the University of Chicago, said: “Working on this animal was like studying an alien from outer space; it’s unlike any other dinosaur I have ever seen.”

The scientists based their findings on new fossils from the Moroccan Sahara as well as specimens in museum collections. ...

http://www.irishexaminer.com/world/spin ... 86094.html
 

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Until recently, Spinosaurus was always depicted as a huge bipedal creature capable of stomping about on its rear legs like a tyrannosaur.
However, this latest skeletal finding shows that it had short hind legs and was probably mostly aquatic - in much the same way that crocodiles spend a lot of their time in and around water.

Look at the pictures of Spinosaurus here:

http://en.wikipedia.org/wiki/Spinosaurus

Then compare them with the pics at Ramon's link above.
 

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Yes!!!!

Avatar-type reptile once lived on Earth

An ecological reconstruction of ikrandraco avatar. An ecological reconstruction of ikrandraco avatar.

Some of the most visually stunning sequences from director James Cameron’s blockbuster movie Avatar involved graceful flying creatures that were ridden by blue human-like beings facing ecological destruction on a moon called Pandora. It turns out that an animal very similar to those Avatar creatures, called ikran, actually did exist on Earth long ago.

Scientists on Thursday announced the discovery of fossils in China of a new species of flying reptile called a pterosaur that lived 120m years ago and so closely resembled the creatures from the 2009 film that they named it after them. It is called ikrandraci avatar, meaning “ikran dragon” from Avatar. And this pterosaur is noteworthy for more than just its resemblance to a movie creature. The scientists said it seems ikrandraci avatar had a throat pouch similar to a pelican’s. It probably fed on small fish from freshwater lakes, flying low over the water and catching prey by skimming its lower jaw into the water, they said. It may have stored the fish in the pouch, they added.

This Cretaceous period pterosaur boasted an unusual blade-like crest on its lower jaw like the one on the movie creatures. ...

http://www.irishexaminer.com/world/avat ... 86222.html
 

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Hadrosaur with huge nose discovered: Function of dinosaur's unusual trait a mystery

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

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

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

http://www.sciencedaily.com/releases/20 ... 110647.htm
 

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How dinosaur arms turned into bird wings

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

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

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

http://www.sciencedaily.com/releases/20 ... 144157.htm
 

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How dinosaurs divided their meals at the Jurassic dinner table

How the largest animals to have ever walked the Earth fed, and how this allowed them to live alongside one another in prehistoric ecosystems is the subject of new research from the University of Bristol and the Natural History Museum, London.

The sauropods -- large, long-necked plant-eating dinosaurs such as Diplodocus and Brachiosaurus -- dominated the land between 210 and 65 million years ago. They were the largest land animals of all time, with the biggest weighing 80 tonnes (more than 11 elephants) and would have needed vast amounts of food.

Despite this, multiple sauropod species often lived alongside each other. The most notable example is the community of the Late Jurassic Morrison Formation, a distinctive sequence of sedimentary rock in the western United States from which over 10 species of sauropod are known. ...

http://www.sciencedaily.com/releases/20 ... 212944.htm
 
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