Long before the arrival of penguins, giant plant-eating dinosaurs roamed Antarctica.
Scientists discovered a fossil tail bone belonging to a titanosaur, a family that included the largest land animals ever to walk the Earth.
Titanosaurs were sauropods, four-legged herbivorous dinosaurs with long necks and tails.
Sauropods included some 150 species whose remains have been found around the world, but never in Antarctica until now.
The new specimen was discovered on James Ross Island by an Argentinian-led team and it consists of section of vertebrae almost 20cm long believed to have come from the middle third of the dinosaur's tail.
Scientists identified it as belonging to a "lithostrotian titanosaur" from the Late Cretaceous period around 70 million years ago.
The discovery is reported in the German journal Naturwissenschaften - The Science of Nature.
Authors Dr Ignacio Alejandro Cerda, from the Conicet research institute in Argentina, and colleagues wrote: "Our finding indicates that advanced titanosaurs achieved a global distribution at least by the Late Cretaceous."
Titanosaurs included the mighty Argentinosaurus, which may have reached 100ft in length.
However, the discovery of a single vertebrae fossil yielded too little information to allow speculation about the dinosaur's species.
http://www.google.com/hostednews/ukpress/article/ALeqM5gB64R8mYY7MnGUKAk15IZ7ZMdLDQ?docId=N0540141324303131758A
Showing posts with label dinosarus. Show all posts
Showing posts with label dinosarus. Show all posts
Tuesday, December 20, 2011
Wednesday, December 14, 2011
New dinosaur species found from museum vaults
Researchers have discovered what they say are the remains of a new horned dinosaur species which has been lying in the vaults of a British museum for nearly a century.
The remains of Spinops sternbergorum, which belongs to the same family as the Triceratops, were excavated from a quarry alongside a large group of fossils in a so-called “bone bed” in Alberta, Canada in 1916.
But the bones were described as “rubbish” by the Natural History Museum’s keeper of Geology at that time, and lay unnoticed for almost 100 years before experts realised they belonged to an undescribed species.
They were rediscovered by a current group of researchers who decided to take another look at the fossils and realised that they were unlike any others known to science.
Dr Andrew Farke, who led the research team, said: “I knew right away that these fossils were something unusual, and it was very exciting to learn about their convoluted history.
“Here we have not just one, but multiple individuals of the same species, so we are confident that it’s not just an odd example of a previously known species,” Dr Farke was quoted as saying a newspaper.
The find means that paleontologists will have to redefine how the horned dinosaur group, plant-eating dinosaurs sporting large horns and bony frills on their necks, are classified.
Dr Paul Barrett, the Natural History Museum’s resident researcher, said: “This discovery is of particular importance as it has implications on the way we use the spines that extend from the bony neck frill, which may have been used for identification between individuals, in our classifications of these animals.
“These embellishments are central to determining relationships between the groups of horned dinosaurs and are a sign of evolutionary relatedness.”
http://www.discoveryon.info/2011/12/new-dinosaur-species-found-from-museum-vaults.html?utm_source=feedburner&utm_medium=email&utm_campaign=Feed:+Discoveryon+%28Discoveryon%29
The remains of Spinops sternbergorum, which belongs to the same family as the Triceratops, were excavated from a quarry alongside a large group of fossils in a so-called “bone bed” in Alberta, Canada in 1916.
But the bones were described as “rubbish” by the Natural History Museum’s keeper of Geology at that time, and lay unnoticed for almost 100 years before experts realised they belonged to an undescribed species.
They were rediscovered by a current group of researchers who decided to take another look at the fossils and realised that they were unlike any others known to science.
Dr Andrew Farke, who led the research team, said: “I knew right away that these fossils were something unusual, and it was very exciting to learn about their convoluted history.
“Here we have not just one, but multiple individuals of the same species, so we are confident that it’s not just an odd example of a previously known species,” Dr Farke was quoted as saying a newspaper.
The find means that paleontologists will have to redefine how the horned dinosaur group, plant-eating dinosaurs sporting large horns and bony frills on their necks, are classified.
Dr Paul Barrett, the Natural History Museum’s resident researcher, said: “This discovery is of particular importance as it has implications on the way we use the spines that extend from the bony neck frill, which may have been used for identification between individuals, in our classifications of these animals.
“These embellishments are central to determining relationships between the groups of horned dinosaurs and are a sign of evolutionary relatedness.”
http://www.discoveryon.info/2011/12/new-dinosaur-species-found-from-museum-vaults.html?utm_source=feedburner&utm_medium=email&utm_campaign=Feed:+Discoveryon+%28Discoveryon%29
Friday, October 28, 2011
Dinosaurs may have migrated: study
Giant plant-eating dinosaurs may have lumbered across hundreds of miles as they made seasonal migrations in search of food and water, scientists believe.
The long-necked "sauropods", which stood on four legs, were the largest animals that ever walked the Earth.
Given their enormous appetites and water needs, their ability to survive in lowland flood plains affected by seasonal dry spells and drought has puzzled scientists.
Now researchers have learned at least one dinosaur species made regular journeys between lowland to highland habitats covering several hundred miles.
The evidence is in the teeth of Camarasaurus, a large sauropod which grew to a length of 60ft and weighed to 18 tonnes.
Fossilised Camarasaurus teeth, found in the US states of Wyoming and Utah, contained a chemical record of the animals' movements during the Late Jurassic period around 150 million years ago.
Different atomic versions of oxygen, or isotopes, occur in the surface water of lowland and highland regions.
These differences remained imprinted in the oxygen from drinking water deposited in the Camarasaurus teeth.
Comparing the oxygen isotopes to those in ancient soil, lake and wetland samples revealed a picture of the dinosaurs' migration patterns.
The researchers, led by Dr Henry Fricke, from Colorado College, US, wrote in the journal Nature: "Camarasaurus populations... must have directly occupied high-elevated regions for at least part of the year before returning to the basin where they died."
http://uk.news.yahoo.com/dinosaurs-may-migrated-study-171726034.html
The long-necked "sauropods", which stood on four legs, were the largest animals that ever walked the Earth.
Given their enormous appetites and water needs, their ability to survive in lowland flood plains affected by seasonal dry spells and drought has puzzled scientists.
Now researchers have learned at least one dinosaur species made regular journeys between lowland to highland habitats covering several hundred miles.
The evidence is in the teeth of Camarasaurus, a large sauropod which grew to a length of 60ft and weighed to 18 tonnes.
Fossilised Camarasaurus teeth, found in the US states of Wyoming and Utah, contained a chemical record of the animals' movements during the Late Jurassic period around 150 million years ago.
Different atomic versions of oxygen, or isotopes, occur in the surface water of lowland and highland regions.
These differences remained imprinted in the oxygen from drinking water deposited in the Camarasaurus teeth.
Comparing the oxygen isotopes to those in ancient soil, lake and wetland samples revealed a picture of the dinosaurs' migration patterns.
The researchers, led by Dr Henry Fricke, from Colorado College, US, wrote in the journal Nature: "Camarasaurus populations... must have directly occupied high-elevated regions for at least part of the year before returning to the basin where they died."
http://uk.news.yahoo.com/dinosaurs-may-migrated-study-171726034.html
Sunday, October 16, 2011
Super-Sized Muscle Made Twin-Horned Dinosaur a Speedster
ScienceDaily (Oct. 14, 2011) — A meat-eating dinosaur that terrorized its plant-eating neighbours in South America was a lot deadlier than first thought, a University of Alberta researcher has found. Carnotaurus was a seven-metre-long predator with a huge tail muscle that U of A paleontology graduate student Scott Persons says made it one of the fastest running hunters of its time.
A close examination of the tail bones of Carnotaurus showed its caudofemoralis muscle had a tendon that attached to its upper leg bones. Flexing this muscle pulled the legs backwards and gave Carnotaurus more power and speed in every step.
In earlier research, Persons found a similar tail-muscle and leg-power combination in the iconic predator Tyrannosaurus rex. Up until Persons published that paper, many dinosaur researchers thought T. rex's huge tail might have simply served as a teeter-totter-like counterweight to its huge, heavy head.
Persons' examination of the tail of Carnotaurus showed that along its length were pairs of tall rib-like bones that interlocked with the next pair in line. Using 3-D computer models, Persons recreated the tail muscles of Carnotaurus. He found that the unusual tail ribs supported a huge caudofemoralis muscle. The interlocked bone structure along the dinosaur's tail did present one drawback: the tail was rigid, making it difficult for the hunter to make quick, fluid turns. Persons says that what Carnotaurus gave up in maneuverability, it made up for in straight ahead speed. For its size, Carnotaurus had the largest caudofemoralis muscle of any known animal, living or extinct.
Persons published these findings in PLoS ONE on Oct.14, with supervisor Philip Currie, a paleontology professor at the U of A.
http://www.sciencedaily.com/releases/2011/10/111014212405.htm
A close examination of the tail bones of Carnotaurus showed its caudofemoralis muscle had a tendon that attached to its upper leg bones. Flexing this muscle pulled the legs backwards and gave Carnotaurus more power and speed in every step.
In earlier research, Persons found a similar tail-muscle and leg-power combination in the iconic predator Tyrannosaurus rex. Up until Persons published that paper, many dinosaur researchers thought T. rex's huge tail might have simply served as a teeter-totter-like counterweight to its huge, heavy head.
Persons' examination of the tail of Carnotaurus showed that along its length were pairs of tall rib-like bones that interlocked with the next pair in line. Using 3-D computer models, Persons recreated the tail muscles of Carnotaurus. He found that the unusual tail ribs supported a huge caudofemoralis muscle. The interlocked bone structure along the dinosaur's tail did present one drawback: the tail was rigid, making it difficult for the hunter to make quick, fluid turns. Persons says that what Carnotaurus gave up in maneuverability, it made up for in straight ahead speed. For its size, Carnotaurus had the largest caudofemoralis muscle of any known animal, living or extinct.
Persons published these findings in PLoS ONE on Oct.14, with supervisor Philip Currie, a paleontology professor at the U of A.
http://www.sciencedaily.com/releases/2011/10/111014212405.htm
Thursday, August 11, 2011
Giant fossil shows huge birds lived among dinosaurs
10 August 2011 Last updated at 11:04 
The fossilised jawbone is nearly twice the length of that of an ostrich, the largest bird found on Earth today
Giant fossil shows huge birds lived among dinosaurs
The fossilised jawbone is nearly twice the length of that of an ostrich, the largest bird found on Earth today An enormous jawbone found in Kazakhstan is further evidence that giant birds roamed - or flew above - the Earth at the same time as the dinosaurs.
Writing in Biology Letters, researchers say the new species, Samrukia nessovi, had a skull some 30cm long.
If flightless, the bird would have been 2-3m tall; if it flew, it may have had a wingspan of 4m.
The find is only the second bird of such a size in the Cretaceous geologic period, and the first in Asia.
The only other evidence of a bird of such a size during the period was a fossilised spinal bone found in France and reported in a 1995 paper in Nature.
Sharing spaceAn overwhelming majority of the birds known from the period would have been about crow-sized, but Dr Darren Naish of the University of Portsmouth said that a second find of an evidently different species suggests that large birds were common at the time.
"This fossil is only known from its lower jaw, so unfortunately we can't say anything at all with certainty about the shape and form of the whole animal.
"If it was flightless and sort of ostrich-shaped, it would have been maybe 2-3m tall and somewhere over 50kg," he explained to BBC News. "If it was a flying animal, then maybe it was shaped like a big albatross or a condor."
Dr Naish also wondered about the dinosaurs with which the enormous birds shared their space.
"I think the really interesting thing is that they're living alongside the big dinosaurs we know were around at the time: big tyrannosaurs, long-necked sauropods, duck-billed dinosaurs," he said. "That opens up loads of questions about ecological interactions that we can only speculate about.
"People have said there weren't big birds when there were big pterosaurs, but now we know there were."
http://www.bbc.co.uk/news/science-environment-14466814
Monday, January 24, 2011
Fossil female pterosaur found with preserved egg
21 January 2011
By Jonathan Amos
Science correspondent, BBC News
A pterosaur has been found in China beautifully preserved with an egg.
The egg indicates this ancient flying reptile was a female, and that realisation has allowed researchers to sex these creatures for the first time.
Writing in Science magazine, the palaeontologists make some broad statements about differences in pterosaurs, including the observation that only males sported a head-crest.
David Unwin, a palaeobiologist in the Department of Museum Studies at the University of Leicester, was part of the research team.
He told the BBC the discovery was astonishing: "If somebody had said to me a few years back that we would find this kind of association, I would just have laughed and said, 'yeah, maybe in a million years', because these sorts of things are incredibly rare."
Pterosaurs, also sometimes referred to as pterodactyls, dominated the skies in the Mesozoic Era, 220-65 million years ago. Although reptiles like the dinosaurs were plodding on the ground below them, they were not actually dinosaurs themselves - a common misconception.
This particular specimen has been dated to about 160 million years ago.
It was found by Junchang Lü and colleagues and excavated from sedimentary rocks in the famous fossil-hunting grounds of Liaoning Province in China. Liaoning has yielded many of the great finds in recent years, including a series of feathered dinos that have transformed thinking on bird evolution.
The new creature is from the Darwinopterus genus, or grouping, but has been dubbed simply as "Mrs T" (a contraction of "Mrs Pterodactyl") by the research team.
The state of the egg's shell suggests it was well developed and that Mrs T must have been very close to laying it when she died.
She appears to have had some sort of accident as her left forearm is broken. The researchers speculate she may have fallen from the sky during a storm or perhaps a volcanic eruption, sunk to the bottom of a lake and then been preserved in the sediments.
"The most important thing about this particular individual is that she has a relatively large pelvis compared to other individuals of the same pterosaur, Darwinopterus," explained Dr Unwin.
"This seems quite reasonable - females lay eggs, they probably need a slightly wider pelvis. And then the really exciting thing is that she has a skull which lacks any kind of adornment or decoration whatsoever. When we look at other individuals of Darwinopterus, we find quite a few individuals with a large crest on the skull.
"We're very confident now that we're dealing with two genders here - males with big crests and small hips, and females with no crest on the skull and large hips."
More at: http://www.bbc.co.uk/news/science-environment-12242596
(Submitted by Dawn Holloway)
By Jonathan Amos
Science correspondent, BBC News
For fossil hunters, it represents one of those breakthrough moments.
A pterosaur has been found in China beautifully preserved with an egg.
The egg indicates this ancient flying reptile was a female, and that realisation has allowed researchers to sex these creatures for the first time.
Writing in Science magazine, the palaeontologists make some broad statements about differences in pterosaurs, including the observation that only males sported a head-crest.
David Unwin, a palaeobiologist in the Department of Museum Studies at the University of Leicester, was part of the research team.
He told the BBC the discovery was astonishing: "If somebody had said to me a few years back that we would find this kind of association, I would just have laughed and said, 'yeah, maybe in a million years', because these sorts of things are incredibly rare."
Pterosaurs, also sometimes referred to as pterodactyls, dominated the skies in the Mesozoic Era, 220-65 million years ago. Although reptiles like the dinosaurs were plodding on the ground below them, they were not actually dinosaurs themselves - a common misconception.
This particular specimen has been dated to about 160 million years ago.
It was found by Junchang Lü and colleagues and excavated from sedimentary rocks in the famous fossil-hunting grounds of Liaoning Province in China. Liaoning has yielded many of the great finds in recent years, including a series of feathered dinos that have transformed thinking on bird evolution.
The new creature is from the Darwinopterus genus, or grouping, but has been dubbed simply as "Mrs T" (a contraction of "Mrs Pterodactyl") by the research team.
The state of the egg's shell suggests it was well developed and that Mrs T must have been very close to laying it when she died.
She appears to have had some sort of accident as her left forearm is broken. The researchers speculate she may have fallen from the sky during a storm or perhaps a volcanic eruption, sunk to the bottom of a lake and then been preserved in the sediments.
"The most important thing about this particular individual is that she has a relatively large pelvis compared to other individuals of the same pterosaur, Darwinopterus," explained Dr Unwin.
"This seems quite reasonable - females lay eggs, they probably need a slightly wider pelvis. And then the really exciting thing is that she has a skull which lacks any kind of adornment or decoration whatsoever. When we look at other individuals of Darwinopterus, we find quite a few individuals with a large crest on the skull.
"We're very confident now that we're dealing with two genders here - males with big crests and small hips, and females with no crest on the skull and large hips."
More at: http://www.bbc.co.uk/news/science-environment-12242596
(Submitted by Dawn Holloway)
Fossil female pterosaur found with preserved egg
21 January 2011
By Jonathan Amos
Science correspondent, BBC News
A pterosaur has been found in China beautifully preserved with an egg.
The egg indicates this ancient flying reptile was a female, and that realisation has allowed researchers to sex these creatures for the first time.
Writing in Science magazine, the palaeontologists make some broad statements about differences in pterosaurs, including the observation that only males sported a head-crest.
David Unwin, a palaeobiologist in the Department of Museum Studies at the University of Leicester, was part of the research team.
He told the BBC the discovery was astonishing: "If somebody had said to me a few years back that we would find this kind of association, I would just have laughed and said, 'yeah, maybe in a million years', because these sorts of things are incredibly rare."
Pterosaurs, also sometimes referred to as pterodactyls, dominated the skies in the Mesozoic Era, 220-65 million years ago. Although reptiles like the dinosaurs were plodding on the ground below them, they were not actually dinosaurs themselves - a common misconception.
This particular specimen has been dated to about 160 million years ago.
It was found by Junchang Lü and colleagues and excavated from sedimentary rocks in the famous fossil-hunting grounds of Liaoning Province in China. Liaoning has yielded many of the great finds in recent years, including a series of feathered dinos that have transformed thinking on bird evolution.
The new creature is from the Darwinopterus genus, or grouping, but has been dubbed simply as "Mrs T" (a contraction of "Mrs Pterodactyl") by the research team.
The state of the egg's shell suggests it was well developed and that Mrs T must have been very close to laying it when she died.
She appears to have had some sort of accident as her left forearm is broken. The researchers speculate she may have fallen from the sky during a storm or perhaps a volcanic eruption, sunk to the bottom of a lake and then been preserved in the sediments.
"The most important thing about this particular individual is that she has a relatively large pelvis compared to other individuals of the same pterosaur, Darwinopterus," explained Dr Unwin.
"This seems quite reasonable - females lay eggs, they probably need a slightly wider pelvis. And then the really exciting thing is that she has a skull which lacks any kind of adornment or decoration whatsoever. When we look at other individuals of Darwinopterus, we find quite a few individuals with a large crest on the skull.
"We're very confident now that we're dealing with two genders here - males with big crests and small hips, and females with no crest on the skull and large hips."
More at: http://www.bbc.co.uk/news/science-environment-12242596
(Submitted by Dawn Holloway)
By Jonathan Amos
Science correspondent, BBC News
For fossil hunters, it represents one of those breakthrough moments.
A pterosaur has been found in China beautifully preserved with an egg.
The egg indicates this ancient flying reptile was a female, and that realisation has allowed researchers to sex these creatures for the first time.
Writing in Science magazine, the palaeontologists make some broad statements about differences in pterosaurs, including the observation that only males sported a head-crest.
David Unwin, a palaeobiologist in the Department of Museum Studies at the University of Leicester, was part of the research team.
He told the BBC the discovery was astonishing: "If somebody had said to me a few years back that we would find this kind of association, I would just have laughed and said, 'yeah, maybe in a million years', because these sorts of things are incredibly rare."
Pterosaurs, also sometimes referred to as pterodactyls, dominated the skies in the Mesozoic Era, 220-65 million years ago. Although reptiles like the dinosaurs were plodding on the ground below them, they were not actually dinosaurs themselves - a common misconception.
This particular specimen has been dated to about 160 million years ago.
It was found by Junchang Lü and colleagues and excavated from sedimentary rocks in the famous fossil-hunting grounds of Liaoning Province in China. Liaoning has yielded many of the great finds in recent years, including a series of feathered dinos that have transformed thinking on bird evolution.
The new creature is from the Darwinopterus genus, or grouping, but has been dubbed simply as "Mrs T" (a contraction of "Mrs Pterodactyl") by the research team.
The state of the egg's shell suggests it was well developed and that Mrs T must have been very close to laying it when she died.
She appears to have had some sort of accident as her left forearm is broken. The researchers speculate she may have fallen from the sky during a storm or perhaps a volcanic eruption, sunk to the bottom of a lake and then been preserved in the sediments.
"The most important thing about this particular individual is that she has a relatively large pelvis compared to other individuals of the same pterosaur, Darwinopterus," explained Dr Unwin.
"This seems quite reasonable - females lay eggs, they probably need a slightly wider pelvis. And then the really exciting thing is that she has a skull which lacks any kind of adornment or decoration whatsoever. When we look at other individuals of Darwinopterus, we find quite a few individuals with a large crest on the skull.
"We're very confident now that we're dealing with two genders here - males with big crests and small hips, and females with no crest on the skull and large hips."
More at: http://www.bbc.co.uk/news/science-environment-12242596
(Submitted by Dawn Holloway)
Friday, January 14, 2011
'Dawn runner' casts light on birth of the dinosaurs
 |
| Eodromaeus ("dawn runner") was discovered in 230-million-year old rocks in the foothills of the Andes |
13 January 2011
Scientists have unveiled one of the earliest dinosaurs yet found, an agile meat-eater from the late Triassic period, some 230 million years ago.
They reconstructed the dinosaur, a probable ancestor of Tyrannosaurus rex, from an almost complete set of bones found in the Valley of The Moon, in northwestern Argentina.
Researchers from Argentina and the US first chanced upon fossilised bones belonging to Eodromaeus in 1996, but it has taken them this long to reconstruct the fragments.
Many of the fossils were covered in iron encrustations and required painstaking work under the microscope before casts could be made and a complete skeleton recreated.
The finished creature claim the researchers, is one of the earliest dinosaurs yet discovered, and could represent the beginnings of the theropod line which eventually leads to T.rex.
"It's very close to the root of the dinosaurs," said lead author Professor Paul Sereno of University of Chicago. "This is a two legged animal, pint-sized if you will. It was agile - we know that from the limb proportions, it had grasping hands with really powerful claws.
"It was a predator, we know that from the grasping hands but also especially from the long curved teeth. It was a meat-eater, a specialist and it was in many ways very close to the original meat-eater, the first of the theropod line that would eventually evolve into huge forms like T.rex."
Ancestral dinosaur
Eodromaeus has also cast light on an earlier discovery by the same team, another two-legged creature called Eoraptor, for which additional bones have now been collected.
The latter creature has been reclassified by the researchers as an early herbivore rather than a predator, and though similar in appearance to Eodromaeus, they now think Eoraptor could be an early example of the sauropods which eventually spawned such giants as Diplodocus.
Even though their descendents may have gone on to great things, neither of the creatures were dominant in their time, and the researchers believe their eventual rise may be down to blind chance, and perhaps some unknown environmental catastrophe.
"Eodromaeus and Eoraptor are punks on the block," said Professor Sereno. "There were other large mammal-like reptiles around that would have been the biggest herbivores and a squat four-legged predator related to alligators that would have swallowed Eodromaeus in one bite."
"Eodromaeus needed some opportunity, some change of events to get the upper hand, so it was extinctions of other animals that were already there which ultimately gave dinosaurs their foot in the door about 200 million years ago."
Dr Paul Barrett, research scientist with the Natural History Museum, said the research was "very interesting" and could bring us closer to the first dinosaur, which he thinks must have lived very shortly before Eodromaeus.
"We have ideas of what dinosaurs looked like from later members of the groups but they're likely to look more similar as they get closer to that ancestral dinosaur," he said.
These two dinosaurs, he said, could represent two of three great dinosaur lineages - the theropods and the sauropods - the other being the ornithischia group to which creatures such as Stegosaurus and Triceratops belonged.
http://www.bbc.co.uk/news/science-environment-12175263
(Submitted by Dawn Holloway)
'Dawn runner' casts light on birth of the dinosaurs
|
| Eodromaeus ("dawn runner") was discovered in 230-million-year old rocks in the foothills of the Andes |
13 January 2011
Scientists have unveiled one of the earliest dinosaurs yet found, an agile meat-eater from the late Triassic period, some 230 million years ago.
They reconstructed the dinosaur, a probable ancestor of Tyrannosaurus rex, from an almost complete set of bones found in the Valley of The Moon, in northwestern Argentina.
Researchers from Argentina and the US first chanced upon fossilised bones belonging to Eodromaeus in 1996, but it has taken them this long to reconstruct the fragments.
Many of the fossils were covered in iron encrustations and required painstaking work under the microscope before casts could be made and a complete skeleton recreated.
The finished creature claim the researchers, is one of the earliest dinosaurs yet discovered, and could represent the beginnings of the theropod line which eventually leads to T.rex.
"It's very close to the root of the dinosaurs," said lead author Professor Paul Sereno of University of Chicago. "This is a two legged animal, pint-sized if you will. It was agile - we know that from the limb proportions, it had grasping hands with really powerful claws.
"It was a predator, we know that from the grasping hands but also especially from the long curved teeth. It was a meat-eater, a specialist and it was in many ways very close to the original meat-eater, the first of the theropod line that would eventually evolve into huge forms like T.rex."
Ancestral dinosaur
Eodromaeus has also cast light on an earlier discovery by the same team, another two-legged creature called Eoraptor, for which additional bones have now been collected.
The latter creature has been reclassified by the researchers as an early herbivore rather than a predator, and though similar in appearance to Eodromaeus, they now think Eoraptor could be an early example of the sauropods which eventually spawned such giants as Diplodocus.
Even though their descendents may have gone on to great things, neither of the creatures were dominant in their time, and the researchers believe their eventual rise may be down to blind chance, and perhaps some unknown environmental catastrophe.
"Eodromaeus and Eoraptor are punks on the block," said Professor Sereno. "There were other large mammal-like reptiles around that would have been the biggest herbivores and a squat four-legged predator related to alligators that would have swallowed Eodromaeus in one bite."
"Eodromaeus needed some opportunity, some change of events to get the upper hand, so it was extinctions of other animals that were already there which ultimately gave dinosaurs their foot in the door about 200 million years ago."
Dr Paul Barrett, research scientist with the Natural History Museum, said the research was "very interesting" and could bring us closer to the first dinosaur, which he thinks must have lived very shortly before Eodromaeus.
"We have ideas of what dinosaurs looked like from later members of the groups but they're likely to look more similar as they get closer to that ancestral dinosaur," he said.
These two dinosaurs, he said, could represent two of three great dinosaur lineages - the theropods and the sauropods - the other being the ornithischia group to which creatures such as Stegosaurus and Triceratops belonged.
http://www.bbc.co.uk/news/science-environment-12175263
(Submitted by Dawn Holloway)
Tuesday, November 30, 2010
Why did mammals evolve to enormous sizes - then get smaller again?
After the dinosaurs were wiped out by a massive meteor strike 65 million years ago, tiny mammals ruled the Earth. But they quickly evolved to be as big as dinosaurs, then evolved to be smaller again. What happened?
This is what paleontologists have long wondered. Scientists knew that extremely large mammals evolved within a few million years after the end of the dinosaurs. As evolutionary biologist Patrick Stephens puts it:
There is a much better fossil record for mammals than for many other groups. That's partly because mammals' teeth preserve really well. And as it happens, tooth size correlates well with overall body size.
But how many of these mammals there were, and why they evolved, have been a mystery until a group of international scientists pooled all the information they had about these giant mammals into one database.
What they discovered was extraordinary: Giant mammals, long believed to be somewhat rare, were common across the entire planet. It seems they grew to fill an ecological niche left by the dinosaurs, aided by a cooling climate and greater amounts of land mass that supported large body sizes. Even more interesting is that mammals didn't reach some "upper biomechanical limit" to their body sizes - they could have grown much larger. The only thing that prevented truly mega-mammals from evolving were climate and available food resources.
According to a summary of the research, published today in Science:
The researchers found that the pattern was indeed consistent, not only globally but across time and across trophic groups and lineages-that is, animals with differing diets and descended from different ancestors-as well. The maximum size of mammals began to increase sharply about 65 million years ago, peaking in the Oligocene Epoch (about 34 million years ago) in Eurasia, and again in the Miocene Epoch (about 10 million years ago) in Eurasia and Africa.
"Having so many different lineages independently evolve to such similar maximum sizes suggests that there were similar ecological roles to be filled by giant mammals across the globe," said [researcher John] Gittleman. "The consistency of the pattern strongly implies that biota in all regions were responding to the same ecological constraints."
Global temperature and the amount of land available as an animal's range are two ecological factors that appear to correlate with the evolution of maximum body size, but Gittleman warned against assigning cause and effect. "A big part of science is seeing patterns, and then producing new hypotheses and testing them," he said. "We have now identified this pattern very rigorously."
The point is, climate change could - over millions of years - lead to giant monsters. So there's something for future geoengineers to aspire to.
You can read more about the scientists collaborating on giant mammal work via their website, or read their paper via Science
This is what paleontologists have long wondered. Scientists knew that extremely large mammals evolved within a few million years after the end of the dinosaurs. As evolutionary biologist Patrick Stephens puts it:
There is a much better fossil record for mammals than for many other groups. That's partly because mammals' teeth preserve really well. And as it happens, tooth size correlates well with overall body size.
But how many of these mammals there were, and why they evolved, have been a mystery until a group of international scientists pooled all the information they had about these giant mammals into one database.
What they discovered was extraordinary: Giant mammals, long believed to be somewhat rare, were common across the entire planet. It seems they grew to fill an ecological niche left by the dinosaurs, aided by a cooling climate and greater amounts of land mass that supported large body sizes. Even more interesting is that mammals didn't reach some "upper biomechanical limit" to their body sizes - they could have grown much larger. The only thing that prevented truly mega-mammals from evolving were climate and available food resources.
According to a summary of the research, published today in Science:
The researchers found that the pattern was indeed consistent, not only globally but across time and across trophic groups and lineages-that is, animals with differing diets and descended from different ancestors-as well. The maximum size of mammals began to increase sharply about 65 million years ago, peaking in the Oligocene Epoch (about 34 million years ago) in Eurasia, and again in the Miocene Epoch (about 10 million years ago) in Eurasia and Africa.
"Having so many different lineages independently evolve to such similar maximum sizes suggests that there were similar ecological roles to be filled by giant mammals across the globe," said [researcher John] Gittleman. "The consistency of the pattern strongly implies that biota in all regions were responding to the same ecological constraints."
Global temperature and the amount of land available as an animal's range are two ecological factors that appear to correlate with the evolution of maximum body size, but Gittleman warned against assigning cause and effect. "A big part of science is seeing patterns, and then producing new hypotheses and testing them," he said. "We have now identified this pattern very rigorously."
The point is, climate change could - over millions of years - lead to giant monsters. So there's something for future geoengineers to aspire to.
You can read more about the scientists collaborating on giant mammal work via their website, or read their paper via Science
Why did mammals evolve to enormous sizes - then get smaller again?
After the dinosaurs were wiped out by a massive meteor strike 65 million years ago, tiny mammals ruled the Earth. But they quickly evolved to be as big as dinosaurs, then evolved to be smaller again. What happened?
This is what paleontologists have long wondered. Scientists knew that extremely large mammals evolved within a few million years after the end of the dinosaurs. As evolutionary biologist Patrick Stephens puts it:
There is a much better fossil record for mammals than for many other groups. That's partly because mammals' teeth preserve really well. And as it happens, tooth size correlates well with overall body size.
But how many of these mammals there were, and why they evolved, have been a mystery until a group of international scientists pooled all the information they had about these giant mammals into one database.
What they discovered was extraordinary: Giant mammals, long believed to be somewhat rare, were common across the entire planet. It seems they grew to fill an ecological niche left by the dinosaurs, aided by a cooling climate and greater amounts of land mass that supported large body sizes. Even more interesting is that mammals didn't reach some "upper biomechanical limit" to their body sizes - they could have grown much larger. The only thing that prevented truly mega-mammals from evolving were climate and available food resources.
According to a summary of the research, published today in Science:
The researchers found that the pattern was indeed consistent, not only globally but across time and across trophic groups and lineages-that is, animals with differing diets and descended from different ancestors-as well. The maximum size of mammals began to increase sharply about 65 million years ago, peaking in the Oligocene Epoch (about 34 million years ago) in Eurasia, and again in the Miocene Epoch (about 10 million years ago) in Eurasia and Africa.
"Having so many different lineages independently evolve to such similar maximum sizes suggests that there were similar ecological roles to be filled by giant mammals across the globe," said [researcher John] Gittleman. "The consistency of the pattern strongly implies that biota in all regions were responding to the same ecological constraints."
Global temperature and the amount of land available as an animal's range are two ecological factors that appear to correlate with the evolution of maximum body size, but Gittleman warned against assigning cause and effect. "A big part of science is seeing patterns, and then producing new hypotheses and testing them," he said. "We have now identified this pattern very rigorously."
The point is, climate change could - over millions of years - lead to giant monsters. So there's something for future geoengineers to aspire to.
You can read more about the scientists collaborating on giant mammal work via their website, or read their paper via Science
This is what paleontologists have long wondered. Scientists knew that extremely large mammals evolved within a few million years after the end of the dinosaurs. As evolutionary biologist Patrick Stephens puts it:
There is a much better fossil record for mammals than for many other groups. That's partly because mammals' teeth preserve really well. And as it happens, tooth size correlates well with overall body size.
But how many of these mammals there were, and why they evolved, have been a mystery until a group of international scientists pooled all the information they had about these giant mammals into one database.
What they discovered was extraordinary: Giant mammals, long believed to be somewhat rare, were common across the entire planet. It seems they grew to fill an ecological niche left by the dinosaurs, aided by a cooling climate and greater amounts of land mass that supported large body sizes. Even more interesting is that mammals didn't reach some "upper biomechanical limit" to their body sizes - they could have grown much larger. The only thing that prevented truly mega-mammals from evolving were climate and available food resources.
According to a summary of the research, published today in Science:
The researchers found that the pattern was indeed consistent, not only globally but across time and across trophic groups and lineages-that is, animals with differing diets and descended from different ancestors-as well. The maximum size of mammals began to increase sharply about 65 million years ago, peaking in the Oligocene Epoch (about 34 million years ago) in Eurasia, and again in the Miocene Epoch (about 10 million years ago) in Eurasia and Africa.
"Having so many different lineages independently evolve to such similar maximum sizes suggests that there were similar ecological roles to be filled by giant mammals across the globe," said [researcher John] Gittleman. "The consistency of the pattern strongly implies that biota in all regions were responding to the same ecological constraints."
Global temperature and the amount of land available as an animal's range are two ecological factors that appear to correlate with the evolution of maximum body size, but Gittleman warned against assigning cause and effect. "A big part of science is seeing patterns, and then producing new hypotheses and testing them," he said. "We have now identified this pattern very rigorously."
The point is, climate change could - over millions of years - lead to giant monsters. So there's something for future geoengineers to aspire to.
You can read more about the scientists collaborating on giant mammal work via their website, or read their paper via Science
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