Thread: Fossil Finds
November 20th 2008, 05:15 PM #226
Re: Fossil Finds
Researchers have reported that roughly 70% of the genome of the woolly mammoth, that became extinct at the end of the last Ice Age, has been reconstructed based upon hair samples removed from the frozen mummified remains of two woolly mammoths whose bodies have been preserved in Siberian permafrost for approximately 20,000 years and 50,000 years respectively.
The DNA sequence, though obviously still not complete, has provided enough information to demonstrate that mammoths were more closely related to modern elephants living today than formerly thought. The two species are so similar the estimated overlap between the mammoth genome and the African elephant genome is 99.4%. This 0.6% difference in their DNA is about half the difference between humans and chimpanzees.
The evidence has led the researchers to conclude that mammoths and Asian elephants diverged about 6-7 mya while the African elephant split off approximately a millions years earlier.
The team also found some elements, such as evidence of inbreeding, that may shed light on why the giant creatures went extinct, which has typically been blamed on human predation, climate change, disease, or combination of any or all the above.
To me, the most exciting aspect of the story is the team’s use of a technique that extracted the DNA from the hair rather than from bone marrow. Previous attempts at getting DNA from hair have only succeeded in removing broken down and fragmented samples. And DNA can be severely damaged by multiple freeze-thaw cycles that allow water and bacteria to penetrate the porous bones. New work with extracting DNA from teeth has been a great improvement though. But now that we know that the keratin sheath of hair appears to protect the DNA inside we have an entirely new way to obtain DNA from ancient remains.
The results are being published in Nature and in a companion piece Darwin 200: Let's make a mammoth in the journal they look at the potential of creating a Mammoth using its DNA.
Sequencing the nuclear genome of the extinct woolly mammoth Abstract
Woolly-mammoth Genome Sequenced
Mammoth genome sequence may explain extinction
Scientists Partially Reconstruct Genome of Extinct Mammoth
Mammoth genome approaching completion
Mammoth Genome Decoded -- Clones on the Way?
Mammoth's genome pieced togetherAlways strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
November 22nd 2008, 02:20 PM #227
Re: Fossil Finds
Researchers have discovered a partial fossilized humerus of a saber-toothed cat that lived near the British coast between one and two million years ago. The fossil was dredged from the sea floor by a trawler in the southern bend of the North Sea, from an area well known for Pleistocene fossil discoveries, primarily from mammoths, mastodons, deer, horses, bear and hippopotamus.
According to analysis, the leg bone belonged to a cat described by Dick Mol, a paleontologist at the Natural History Museum in Rotterdam, as being as heavy as a small horse, approximately 880lbs. (400kg). Mol and his colleagues compared the find to fossils of saber-tooth cats found in Germany and concluded it probably came from Homotherium crenatidens. Analysis of it suggests it was most likely bigger than other H. crenatidens specimens known from other European sites.
Homotherium is a genus of large cat (there are something like a dozen species IIRC) that once wandered Africa, Eurasia, North & South America that died out roughly 10,000 years ago. Homotherium is a type of saber-tooth known as a “scimitar cat” because their canine teeth are basically shorter, more slender and more finely serrated than those found in cats like Smilodon, the epitome of saber-tooths.
After examining the fossil they determined it was from the early Pleistocene based on how mineralized the bone had become.
Much has been made of the fact that It is the furthest north this species has ever been found, and the first time remains have come from the North Sea, but as the articles makes clear, the remains of another saber-tooth, a Homotherium latidens, had previously been uncovered from the North Sea. And the fact that the remains of Homotherium have also been found in Alaska means that the discovery shouldn’t have come as much of a surprise.
Big cat fossil found in North Sea
Big sabre-tooth scimitar cat fossil found in North SeaAlways strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
November 26th 2008, 08:26 PM #228
Re: Fossil Finds
Yikes, it’s the attack of the Turtles! A little over a month ago there was another discovery concerning the origin of the turtle shell. I covered that
HERE. Earlier this week the first aquatic turtle was discovered, which I just finished covering HERE. And now Dave G has started a thread about a new (well, 220 myo) Chinese discovery of a long-bodied turtle with teeth that had a partial shell which covered its belly but not its back HERE.
It was just this Summer I heard someone complaining about the lack of early turtle fossil material. Looks like that situation is rapidly changing.Always strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
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November 29th 2008, 10:15 PM #229
Re: Fossil Finds
Research on exactly how fossils form has produced two new studies with somewhat surprising results.
The first deals with how the delicate fossils seen in the Cambrian-aged Burgess Shale survived conditions that should have destroyed them, namely being deeply buried in the Earth’s crust and getting heated to over 300°C (572°F) previous to tectonic forces thrusting them up by to form a mountainous ridge in the Canadian Rockies in British Columbia.
Apparently, according to a team of British researchers, it was the heat that helped preserve the fossils.
As the fragile organic tissues got heated up minerals began forming and began protecting the delicate details.
As team member Alex Page exclaimed: “This provides a whole new theory for how fossils form. The deep heating may not have cremated them, but it certainly left them stone baked.”
Deep Heat Solution To 500-million Year Fossil Mystery
The second details how bacterial biofilms created from bacterial decay may have been instrumental in preserving the embryos of ancient marine creatures and can how they can duplicate the same fossilization result in modern embryos.
It would seem that this isn’t really as much a shock as some indicate considering the recent research that identified what had previously been thought to be preserved soft tissue inside T rex bones as being the result of bacterial biofilm. So it would seem that bacteria, usually associated with breaking down remains so they don’t fossilize, may play a more important role than previously thought.
As one of the leaders of this research team, Indiana University Bloomington biologists Elizabeth Raff remarked, “This work is important because it helps us understand fossilization as a biological as well as geological process.”
Bacteria may play big role in forming fossils
Bacterial Biofilms As Fossil MakersAlways strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
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December 3rd 2008, 04:18 PM #230
Re: Fossil Finds
The fossil of the first chaoyangopteridae (toothless pterosaurs) has been found outside of China in Brazil, and it’s much bigger than any other example from this family which includes Chaoyangopterus, Eoazhdarcho, Eopteranodon and Jidapterus.
The new find was originally unearthed in the Crato Formation of the Araripe Basin in northeastern Brazil, an area well known for its incredibly well-preserved fossils and is dated at being approximately 115 myo (toward the end of the Early Cretaceous). Its discovery, roughly 10,000 miles from its closest known relatives in China reveals just how little is actually understood about their distribution and evolutionary history.
The fossil consists of a partial skull and had been gathering dust in a German museum for several years before being identified by Mark Witton a postgraduate student in the school of Earth and Environmental Science at the University of Portsmouth in Great Britain. From the skull Witton was able to extrapolate that the pterosaur had a wingspan of 5 meters (16.4’) and stood over a meter (3.28’) tall at the shoulder.
Some of the Chinese members of this group of flying reptiles are just 60cm (just under 2’) which is the length of the skull of the new species which Witton named Lacusovagus magnificens (“Magnificent Lake Walker”) after the body of water in which the skull was buried.
While the largest by far of the chaoyangopteridae, Lacusovagus was still considerably smaller than some of the flying reptiles known to have teeth such as Quetzalcoatlus which had a wingspan that was at least twice as long.
Apparently the fossilized section of skull was preserved in a peculiar manner which has made interpretation a bit problematic.
“Usually fossils like this are found lying on their sides but this one was lying on the roof of its mouth and had been rather squashed which made even figuring out whether it had teeth difficult. Still, it’s clear to see that Lacusovagus had an unusually wide skull which has implications for its feeding habits – maybe it liked particularly large prey,” observed Witton, who also noted that “the remains are very fragmentary, however, so we need more specimens before we can draw any conclusions.”
Witton's findings were published in last month’s journal Palaeontology.
New Giant Toothless Pterosaur Species Discovered
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December 7th 2008, 08:55 PM #231
Re: Fossil Finds
Climate change rather than human predation appears to have been the cause of the extinction of the enormous European cave bear, Ursus spelaeus, according to new research by an Austrian British team that also found that they died off 27,800 years ago, approximately 13,000 years earlier than previously thought.
The new date coincides with the last Ice Age in Europe, a period known as the Last Glacial Maximum, when the dramatic decrease in temperatures resulted in a freeze that killed off or at least greatly reduced the vegetation that was their primary food source.
As Professor Anthony J. Stuart of the Natural History Museum in London and the University of Durham, and one of the researchers involved, said: “The disappearance of the cave bear around 27,500 years ago was probably due to the significant decline in quantity and quality of plant food, which in turn was the result of marked climatic cooling.”
Yeah it appears that the gigantic Pleistocene cave bears were predominantly vegetarians. Morphological features of their chewing apparatus have already suggested non-predatory behavior as well as important adaptations to a tough vegetarian diet, so this doesn’t come as a big surprise. But now chemical analysis of their bone collagen and study of their teeth indicate they were primarily vegetarian, in contrast to the omnivorous diet of the modern brown bear.
Ursus spelaeus, which was considerably larger than today’s brown bear, was also much more limited in its geographic distribution. They only lived in a region covering modern day Spain stretching eastward to the Ural Mountains in western Russia. Scientists feel that the foremost reason they didn’t spread further East was that they were intolerant of extreme temperatures.
So when their somewhat specialized food supply deteriorated, coupled with the limited geographic distribution (only from Spain to the Ural Mountains in Russia), Ursus spelaeus was doomed with no credible evidence for human involvement in this equation. Some past reports have suggested that the cave bears' demise was linked to over-hunting by man.
Before this new study many thought that cave bears went extinct roughly 15,000 years ago. This, the researchers believe, was because earlier works had dating errors and sometime confused remains of cave bears with those from brown bears.
"Our work shows that the cave bear, among the megafauna that became extinct during the Last Glacial period in Europe, was one of the earliest to disappear," said Dr. Martina Pacher of the Department of Paleontology at the University of Vienna. "Other, later extinctions happened at different times within the last 15,000 years."
Some of the other megafauna referred to by Pacher here include woolly mammoth, woolly rhinoceros, giant deer and cave lion – all of which vanished after the glaciers from the last Ice Age had retreated during the warmer Holocene period.
Still, the possibility that cave bears survived considerably longer in isolated pockets, perhaps in southern or eastern Europe, cannot be overlooked.
Extinction chronology and palaeobiology of the cave bear (Ursus spelaeus) Abstract
Climate Change Wiped Out Cave Bears 13 Millennia Earlier Than Thought
Cave bears killed by Ice Age, not hunters: study
Vegetarian cave bear 'starved to death' during Ice Age
Did vegetarian diet kill off giant cave bears?Always strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
December 11th 2008, 02:04 AM #232
Re: Fossil Finds
With a name sounding like it came from some low grade Sci Fi movie from years ago, or perhaps a professional wrestler that never quite made it to the big time, a new Abelisaurid dinosaur, a snub-nosed carnivorous theropod, has been discovered in the Late Cretaceous Huincul Formation near the town of El Chocón in northwestern Patagonia in Argentina.
It has been named Skorpiovenator bustingorryi, or “Bustingorry’s scorpion hunter,” in honor of the late owner of the site which was over-run with scorpions. So no, despite its name Skorpiovenator wasn’t an insectivore (or “arachnivore”).
The roughly 93 myo nearly complete and articulated specimen is missing only parts of its tail and the majority of its forearms. Skorpiovenator was approximately 6 meters long and had a short, stout skull heavily ornamented with ridges, furrows and tubercles, features that typically occur in abelisaurids.
The team, led by Juan Canale a paleontologist with the nearby Ernesto Bachmann Municipal Museum in El Chocón, has described Skorpiovenator as one of the most complete and informative abelisaurids yet known. Its completeness offers priceless skeletal details that helped to clarify character distribution within abelisaurid theropods.
In fact, phylogenetic examinations conducted by Canale and his colleagues found that all the South American abelisaurids, including [i]Aucasaurus[/i ], Carnotaururs, Ekrixinatosaurus, Ilokelesia, and the new Skorpiovenator have been grouped together into a new clade (or sub-clade) they designated Brachyrostra, meaning “short snouts.”
Since Skorpiovenator shared its space with other carnivorous dinosaurs, including other abelisarids, and the enormous Mapusaurus, a 3 ton, 12 meter (40’) long carcharodontosaurid, it is thought that the different predators probably had different prey and hunting strategies much like what is seen in the Africa savannah today where multiple large carnivores co-exist.
The last reason this is an important discovery has to do with teeth. Since teeth are much more prevalent in the fossil record than any other part of the skeleton and because carnivorous dinosaurs are known to shed and grow new teeth throughout their lives, if you can properly identify what kind of tooth matches which dinosaur, then you can identify many more specimens and tell how long a species of dinosaur inhabited the area.
Canale’s team believes that some teeth once thought to belong to carcharodontosaurids appear to more closely resemble to the teeth of Skorpiovenator, which means that they may actually belong to abelisaurids. If true, abelisaurids like Skorpiovenator may be more important in trying to determine what South America during the Cretaceous was like.
New carnivorous dinosaur from the Late Cretaceous of NW Patagonia and the evolution of abelisaurid theropods Full paper, though occasional problems loading
New carnivorous dinosaur from the Late Cretaceous of NW Patagonia and the evolution of abelisaurid theropods Abstract, if link above doesn’t work
A New Discovery: Skorpiovenator, the Scorpion HunterAlways strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
December 13th 2008, 06:51 PM #233
Re: Fossil Finds
Not exactly a new fossil find, rather a new ultra high tech examination of an old one. One of the ten 150 myo Archaeopteryx fossils known to exist, all of which have already undergone detailed visual examinations as well as computed tomography (CT) scans, is now for the first time going to be analyzed by x-ray fluorescence imaging, a technology developed by the Department of Energy and being perfected by physicists at Stanford Synchrotron Radiation Lightsource (SSRL) at the SLAC National Accelerator Laboratory.
By utilizing this technique researchers hope to chart the chemical elements contained within the fossil itself since, basically, every specific chemical within the fossil emits a specific frequency of fluorescent light that can identify it are picked up by the SSRL.
As Uwe Bergmann, a physicist at SLAC explains, "What you normally can't see are the chemical elements from the original organism that might still be present in the fossil. Using X-ray fluorescence imaging, we can bring these elements to light, getting a better look at the fossil and learning more about the original animal.”
Of course, any information concerning the elements and chemical compounds found within Archaeopteryx will provide valuable data that can be compared to what we find in modern birds thus offering us a valuable insight into the evolution of modern birds.
Additionally, this new research could also disclose more about the fossilization process itself. Knowing better how the process takes place and what is actually preserved during the process will allow scientists to figure out a great deal more about ancient extinct organisms and evolution.
The tests started last Friday (Dec. 11) and have already detected the presence of several elements including calcium, copper, manganese, phosphorous, sulfur and zinc. Bergmann continues the examination of the fossil hoping to find some organic compounds as well.
As for theArchaeopteryx fossil itself, this specimen is sometimes known as the "Thermopolis Fossil" (after its present location in a small private museum, the Wyoming Dinosaur Center, in Thermopolis, Wyoming) is one of the most complete and best preserved examples of Archaeopteryx, specifically its head and feet (the latter revealed that it lacked a feature universal in birds – a reversed toe – as well as having a deinonychosaurs-like hyper-extendible second toe). It is preserved on a 40cm (16”) square slab of limestone.
Nobody knows exactly when and where it was cut from Germany's Solnhofen limestone, the source for the Archaeopteryx discovered so far. It appeared after the death of a private Swiss collector 40 years ago and was first (scientifically) described in a 2005 issue of Science.
Darwin's Dinobird Fossil Analyzed at SLAC National Accelerator Laboratory
Technology gets fossil to reveal its secrets
A new look at dinosaurs through hi-tech eyes news report video
Image of fossilAlways strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
December 15th 2008, 11:39 PM #234
Re: Fossil Finds
The oldest threads of silk from a spider web have been found preserved in a piece of amber picked up by an amateur fossil hunter on a beach on England’s southern coast famous for fossilized dinosaur tracks near Bexhill, in East Sussex.
A team led by Professor Martin Brasier, a palaeobiologist at Oxford University, said that the 140 myo webbing consists of tiny threads approximately 1mm (0.04”) in length that are linked to each other in a pattern similar to those of modern orb web spiders known for their roughly circular spiral webs used to catch flying insects.
Brasier noted that the find "is absolutely consistent with an orb web spider. The spacing between the threads suggest they were the structural struts onto which a web was spun. The treads themselves are made of two pieces joined together just like a modern web.” He also observed that, "We have also found a few tangles of web in the amber. It is amazing to see something so delicate that has survived so many million years."
This discovery implies that orb web spinning spiders lived considerably earlier than was thought, at a time prior to flowering plants appearing which appeared to set off an explosion in flying insects.
Bits of charred bark and burnt sap inside the amber have led the scientists to think that the web became trapped in resin in the aftermath of a forest fire when the tree that produced the sap (that would later become the amber) was damaged in a fire and produced the droplets of resin to protect itself from infection.
Brasier and her colleagues hope that by analyzing other pieces of amber from the same deposits they might be able to learn more about the spiders from that period and their prey. The site itself is also thought to be the first important amber deposit unearthed in Britain.
The previous record holder for the oldest sample of spider silk is a 130 myo Lebanese specimen found in amber though that was a single 4mm strand. A 110 myo spider web complete with prey was discovered in Spain and was also encased in amber. This is due to the fact that fragile, gossamer structures like spider webs aren’t ordinarily fossilized and can only be preserved if they have been caught up in resin such as amber.
The fossil record shows that spiders themselves (more likely to be found than their webs) have had web producing spinnerets for roughly 380 million years though the oldest known fossilized orb spider is only, IIRC, 120 myo.
Scientist says he has found oldest spider web
World's oldest spider web found on beach
World’s Oldest Spider Web Discovered In Britain
Egad! Oldest Spider Web Dates Back to Dinosaur EraAlways strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
December 16th 2008, 04:13 PM #235
Re: Fossil Finds
Hmm. I think Spidey's web-spinning mechanism's only date to the early 1960s, probably not old enough to fossilize.
And that Peter Parker kid sure doesn't seem to show his age. I wonder if there's some issue there for the "apparent age/apparent history" controversy?
Anyway, getting back to real spideys...
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December 18th 2008, 07:17 PM #236
December 18th 2008, 07:17 PM #237
Re: Fossil Finds
A couple of new dinosaur fossil discoveries in South America and Africa have made the news.
The first has to do with a new type of carnivorous dromaeosaur, or raptor, found in the Patagonia region of Argentina that was 5 to 6˝ meters (16˝ to 21’) long (depending how long the tail was) and lived approximately 70 mya.
The fossil, which was named Austroraptor cabazai, was incomplete, consisting primarily of bones from the head, neck, back and feet, and was unearthed at Bajo de Santa Rosa, in Rio Negro province, a region known for producing several species of herbivorous dinosaurs.
The team, led by paleontologist Fernando Novas of the Museo Argentino des Ciencias Naturales, says that Austroraptor, besides being roughly three times as long as Velociraptor, had several unusual characteristics that makes it unique among raptors.
It had short forearms making it the only raptor found with short arms. I don’t know if they are anything like T rex short, but they along with its robust thigh bones (not to mention it’s estimated weight of at least 800lbs. (around 370kg), ensure this was no flyer like some of its dromaeosaurid kin.
But then, oddly, it had a meter-long skull that resembles what is found on pterodactyls. Being that there was also a much smaller South American dromaeosaur with a similar long-snouted skull, it appears that there was a diverse group of tapering skull dromaeosaurs inhabiting the region.
Novas also observed that beside there was still a wide range of raptors still living in South America after their counterparts went extinct. "It means that raptors here had very different evolutionary paths from those up north," he said.
"Bizarre" New Dinosaur: Giant Raptor Found in Argentina
New dinosaur species similar to T.rex is uncovered in Argentina
Giant, meat-eating raptor dinosaur discovered in Argentina
The other discovery comes from south-east Morocco, near the Algerian border where two new species of dinosaur were discovered; one a new type of pterosaur (flying reptile), and the other being a new type of sauropod (long neck & tail four-legged herbivore) that may also represent a new genus as well, that lived roughly 100 mya.
"Finding two specimens in one expedition is remarkable, especially as both might well represent completely new species," said University College Dublin (UCD) paleontology graduate student Nizar Ibrahim, who led the expedition and was accompanied by Dr David Martill, a reader in Palaeobiology at the University of Portsmouth (who tried to excavate the site a quarter of a century ago before being driven away by sandstorms).
The sauropod remains consisted of a leg bone measuring over a meter (3.28’) in length that indicates that the dinosaur it came from was almost 20 meters (65’) long. Martill notes that “Plant eaters are uncommon in this deposit, extremely rare in this region and to find one this large is very exciting. It’s a major discovery.”
The pterosaur find is also rare in that being made for flight their bones were light and fragile, meaning that most of the time all that is ever found is teeth and fragmented bone pieces. But this time a large section of beak was discovered which may provide unique insights into the creature.
The team traveled approximately 5000 miles overland through deserts, over mountains, fighting sandstorms, floods and blizzards and encountering one difficulty after another to get to, obtain and return with the fossils.
They also found some dinosaur tracks at the site, including some where they were walking along the same trail. They also uncovered a new species of fish and some pieces from crocodiles as well.
New Species Of Prehistoric Giants Discovered In The Sahara
Giant Dinosaur Fossil Found in Sahara Desert
Fossil-hunters battle Sahara storms to find dinosaur prize
New dinosaurs discovered by British scientists in Sahara desertAlways strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
December 18th 2008, 08:40 PM #238
Re: Fossil Finds"To announce that there must be no criticism of the President, or that we are to stand by the President, right or wrong, is not only unpatriotic and servile, but is morally treasonable to the American public."
--Theodore Roosevelt , May 7, 1918
To be a patriot, one had to say, and keep on saying, "Our country, right or wrong," and urge on the little war. Have you not perceived that that phrase is an insult to the nation. Mark Twain, "Glances at History," 1906
December 19th 2008, 05:35 PM #239
Re: Fossil Finds
New research from Montana State University indicates, after examining the fossilized remains found atop large nests of eggs, that the adult males from three types of carnivorous dinosaurs (Troodon formosus, Oviraptor philoceratops and Citipati osmolskae) were the sole care-givers for the eggs and very well may have been polygamous, mating with numerous different females who laid their eggs in one large clutch and taking care of all the eggs at the same time. The nests contained between 22 and 30 eggs each.
It was the recurring discovery of adult theropod dinosaurs atop or next to egg clutches found in locations like Montana and Mongolia that lead MSU paleontologist and team leader David Varriccho and his colleagues to investigate the type and extent of care demonstrated by these various dinosaurs for their eggs and young.
So the team started by examining clutch sizes and analyzing the fossilized bones of the adults associated with the nests. They compared clutch sizes with those of their closest living ancestors (birds and crocodiles), finding that large clutches seem to take place in those animals with male-only care. Clutch volumes tend to be bigger in species without maternal care, because the females can devote more resources to laying the eggs if they don’t have to also take care of the eggs.
While rare among birds in general, “male-only care is common among large flightless birds like ostriches, emus and rheas and the South American tinamous,” Varrichio said. Previous studies had determined that the dinosaurs involved in the research shared several reproductive features with living birds (both produced asymmetric eggs with nearly identical eggshells, for example) and theropods are the group that it is thought birds evolved from.
But to test whether this connection was valid the bones from the adults were also examined. This revealed that none of them held any of the tissue usually linked with egg-laying females. Minerals for egg-laying are stored as extra tissue within the hollow limb bones of modern birds. This lack of spongy tissue, or medullary bone, indicated that the adults were male.
"This is important research in that it tells us about when and how an important aspect of the modern avian reproductive system came to be," noted co-author Florida State University associate professor and co-author of the paper published in the journal Science, Greg Erickson. "Prior to the discovery that birds are in fact theropod dinosaurs, these animals seemed almost alien among reptiles and scientists were at a loss to explain how the modern avian condition evolved.”
The team concluded that the paternal care in both troodontids and oviraptorids indicates that this male-only care system evolved prior to the appearance of the first birds and likely represents birds' ancestral condition.
Still, these fossils present many questions since we don't know exactly what the male dinosaurs were actually doing perched atop of the eggs. They may have been incubating them, protecting them, or possibly shading them from the sun (some of the specimens were unearthed in classic brooding positions). We also don’t have an explanation for the dinosaurs' abrupt death while taking care of the nests though some speculate that the Mongolian specimens might have died as a result of sandstorms or collapsing sand dunes.
Avian Paternal Care Had Dinosaur Origin Abstract
Montana State study finds super dads, possible polygamists among dinos
Daddy Dinosaurs May Have Tended Developing Eggs
Daddy day-care: dinosaur fathers guarded the eggs
Dinosaur day care dads
Dinosaur Dads Played "Mr. Mom"?Always strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
January 1st 2009, 09:15 PM #240
Re: Fossil Finds
The well-preserved and nearly complete skull of what appears to be the most primitive known cheetah has been discovered in the Linxia basin in the Gansu province of northwestern China and suggests that the big cats originated not in the Americas as has been previously believed, but in the Old World instead.
The skull has been dated at being from between 2.15 and 2.55 mya and is similar in both shape and size to skulls from modern cheetahs. But the skull also reveals a unique combination of primitive and derived characters as well with the latter being seen in its teeth which were extremely primitive. And it is these primitive characteristics that strongly suggest this new find called Acinonyx kurteni is the oldest known ancestor of all cheetahs.
Since the skull had enlarged frontal sinuses (providing the distinctive bulge on its forehead and snout as seen in modern cheetahs) and enables increased air intake which is necessary for sprinting.
"So running fast and becoming really good at it was one of the first steps in cheetah evolution. Later, the teeth changed as well," noted the paper’s lead author, Dr. Per Christiansen at the Zoological Museum in Copenhagen. The find also suggests that the many unusual skull and dental traits up till now thought to be characteristic of cheetahs evolved gradually.
The cheetah’s evolutionary history hasn’t been well understood due to a lack of fossils to study, with cheetah-like animals being discovered throughout Africa, Europe, Asia, the Indian subcontinent, and even North America that date to between 3.2 million and 2,000 years old. This has led to considerable debate concerning where these big cats originated.
The age and morphology of Acinonyx kurteni supports an Old World origin of the cheetah family, not a New World one, as has been suggested. This is because the primitive dental features would have been more developed in the Chinese fossil if cheetahs had come from the Americas.
Furthermore, the team suggests that due to the new information some of the other known Pliocene-Pleistocene cheetahs, which have been identified from isolated fossilized teeth, may have been misidentified and should be attributed to leopards or other similar-sized pantherine cats or pumas.
But not everyone is convinced. Deng Tao, a professor at the Chinese Academy of Sciences in Beijing, claims that the skull is not from a new species, but from a previously known one called Sivapanthera linxiaensis. Deng also said that the newly discovered skull wasn’t an intact original, but rather a compilation from bones of various individuals and possibly even various species. This description seems to contradict news account which has described the skull as “superbly preserved.”
Dr. Ji Mazák of the Shanghai Science and Technology Museum in China, co-author of the paper, strongly disagrees. He asserts that Deng studied a different species and that his fossils resembled the genus Panthera (which includes lions, tigers and leopards) rather than that of Acinonyx (the genus cheetahs are in).
Mazák also noted that his team had carefully examined their cranium and determined that all of its parts—including teeth—belonged to the same individual.
A primitive Late Pliocene cheetah, and evolution of the cheetah lineage Abstract
Ancient Cheetah Fossil Points to Old World Roots?
Fossilised skull suggests cheetahs evolved in Asia not Americas
Big cats traced to Asia, not AmericaAlways strive to keep an open mind – but not so open that your brains fall out!Still afeared of & dodging The PINTM
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