Missing Link For Wonky-Eyed Fish Discovered - The face of a flounder, sole, halibut or other flatfish looks like a hodgepodge of mismatched puzzle pieces forced together, with eyes that don't seem to match one another nor the orientation of the animal's mouth.
This is because, as these fish mature, one eye migrates over the top of the fish's head, coming to rest above the other eye, so both are on the same side of the head. A new fossil discovery has shed light on how this strange trait came about.
This is the skeleton of the primitive flatfish Heteronectes shown as an x?ray image (top), photograph before preparation (middle), and photograph after preparation (bottom).
Matt Friedman, a paleobiologist at University of Oxford in the United Kingdom, found a sort of flatfish missing link in a drawer of unidentified fish fossils in the Natural History Museum of Vienna, Austria.
The left eye of this single specimen, a 50-million-year-old fish called Heteronectes, has migrated toward the top of the skull, but not all the way over. The eye's position places this fish in between the modern, asymmetrical flatfishes and their distant ancestors, which had symmetrical faces with eyes on opposite sides of the face.
There are about 600 species of flatfish, many of which are caught and eaten by humans. Scientists know why these fish have two eyes on one side of their faces. As free-swimming larvae, these fish have eyes on both sides of their heads. But as adults, they lie on the seafloor. By shifting one eye up and over their body's midline, flatfish avoid pointing one eye down toward the sediment.
But how this arrangement emerged has caused debate among scientists, since no living fishes show any intermediate form. At one point, flatfishes were among the examples some critics used to attack gradual evolution and natural selection that occurs over many generations, in favor of dramatic changes that could occur within a single generation, Friedman said.
"What this fossil does is it provides a clear example of precisely that intermediate morphology," Friedman told LiveScience.
This discovery indicates that asymmetric faces were among the first features associated with living flatfishes to evolve, Friedman writes in the July issue of the journal Vertebrate Paleontology.
Researchers have known about another ancestor to modern flatfish, called Amphistium, for some time, however, its fossils have not been studied in detail, as Friedman has done with Heteronectes.
The Heteronectes skeleton was excavated from Bolca in northern Italy at a fossil fish-rich site that contains the remains of an ancient coral reef. ( LiveScience.com )
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Jurassic Lark? Expedition to Seek Living Dinosaurs in Africa - A young Missouri man has turned to the Internet in search of investors for his expedition into the remote jungles of Africa seeking to document undiscovered flora and fauna. That is not so unusual, but one of the creatures he hopes to find is: a living dinosaur.
The region Stephen McCullah, the organizer of the expedition, has chosen to explore is the reputed home of the Mokèlé-mbèmbé, a dinosaur-like creature said to be up to 35 feet long (11 meters), with brownish-gray skin and a long, flexible neck. Many locals believe that it lives in the caves it digs in riverbanks, and that the beast feeds on elephants, hippos and crocodiles.
McCullah posted his pitch on Kickstarter.com asking for $27,000 in donations so that he and his friends can launch the Newmac Expedition, "one of the first expeditions in this century with the goal of categorizing plant and animal species in the vastly unexplored Republic of the Congo." The preliminary four-man venture is slated to launch June 26.
Though the team members largely lack formal education in biology or zoology, they "anticipate discovering hundreds of new insect, plant and fish species during the course of our research. There is also the legitimate hope of discovering many reptile and mammalian species. We have received reports...in the region of eyewitnesses seeing canine-sized tarantulas, large river dwelling sauropods [dinosaurs], and a species of man-eating fish," McCullah wrote on the website.
Never mind dinosaurs, which have been extinct for millions of years, for a moment. Finding a spider the size of a dog would be remarkable enough, as the largest-known tarantula, the Goliath birdeater, lives in South America and has a leg span of "only" a foot.
When asked if he really expected to discover monster tarantulas and dinosaurs, McCullah told Life's Little Mysteries, “We don't necessarily expect to find concrete evidence of Mokèlé-mbèmbé (or any other creatures claimed to have been seen in the region) on the first expedition, but we believe there's a good chance during that initial three months that we will find hard evidence of its presence in the area if it is there."
Even if McCullah's team finds that evidence, most cryptozoologists (those who search for unknown or hidden animals) believe that only a live or dead specimen would convince mainstream scientists that animals such as Bigfoot or Mokèlé-mbèmbé exist — the blurry photos and videos, footprints and eyewitness reports that make up the vast majority of the evidence for these creatures are simply not enough. McCullah and his team will need specialized equipment to capture these animals — and a living dinosaur would require a pretty big net.
"We are in the process of looking at live methods for capture of large animals," McCullah said. "We will be attempting to bring a tranquilizer rifle, but there are many issues and unknowns we will have to overcome to subdue an animal like Mokèlé-mbèmbé with a tranquilizer gun."In his Kickstarter pitch, McCullahnoted that there have been several previous expeditions to the Congolese jungles in search of large unknown animals (including Mokèlé-mbèmbé), and yet they all failed to find good evidence. He believes that his group's youth and enthusiasm will help them succeed where others have failed. The arsenal of cutting-edge technology they plan to bring should help as well: "We will be utilizing satellite images, trail cameras, a Thermal camera to track animals, and sonar to search through the murky waters." ( LiveScience.com )
Dinosaurs had fleas too _ giant ones, fossils show - In the Jurassic era, even the flea was a beast, compared to its minuscule modern descendants. These pesky bloodsuckers were nearly an inch (25 millimeters) long.
New fossils found in China are evidence of the oldest fleas _ from 125 million to 165 million years ago, said Diying Huang of the Nanjing Institute of Geology and Paleontology. Their disproportionately long proboscis, or straw-like mouth, had sharp weapon-like serrated edges that helped them bite and feed from their super-sized hosts, he and other researchers reported Wednesday in the journal Nature.
Handout photo released by the Nature magazine and obtained on Feburary 28, 2012 shows a female flea from the early Cretaceous period. The giant dinosaurs that roamed the world some 150 million years ago shared the planet with equally daunting parasites: blood-gobbling fleas that were up two centimetres (almost an inch) long. –AFP PHOTO / Nature / D. Huang
Scientists figure about eight or more of today’s fleas would fit on the burly back of their ancient ancestor.
‘‘That’s a beast,’’ said study co-author Michael Engel, entomology curator at the Natural History Museum at the University of Kansas. ‘‘It was a big critter. I can’t even imagine coming home and finding my miniature schnauzer with one or more of these things crawling around on it.’’
The ancient female fleas were close to twice the size of the males, researchers found, which fits with modern fleas.
Engel said it is not just the size, however, that was impressive about the nine flea fossils. It was their fearsome beak capable of sticking into and sucking blood from the hides of certain dinosaurs, probably those that had feathers.
These flea beaks ‘‘had almost like a saw running down the side,’’ Engel said. ‘‘This thing was packing a weapon. They were equipped to dig into something.’’
While the ancient fleas were big, they had one disadvantage compared to modern ones: Their legs were not well developed. Evolving over time, fleas went from crawling to jumping, Huang said.
‘‘Luckily for the land animals of the Mesozoic, these big flat fleas lacked the tremendous jumping capacity that our common fleas have,’’ said Joe Hannibal of the Cleveland Museum of Natural History. He was not involved in the study, but he praised it as useful and interesting.
Just finding the fleas was a stroke of luck, Huang said. He first found one in a Chinese fossil market and mentioned it to someone at his hotel. The other guest showed him a photo of another fossilized flea, telling him it was from Daohugou in northeastern China, where there is a famous fossil bed from about 165 million years ago. Huang went there and found fleas preserved in a brownish film of volcanic ash. The grains of rock were so fine you could see antennae and other details of the fleas, he said.
Modern fleas get engorged after they feast on blood, but these did not seem engorged, Engel said.
It should not seem very surprising that large fleas existed more than 100 million years ago. If you go back even farther in time, ancestors of dragonflies and damsel flies had 3-foot-long (1 meter-long) wingspans, Engel said. ( Associated Press )
T. Rex may have eaten one another - A team of researchers reports Friday that huge tooth marks on Tyrannosaurus rex bones indicate the ancient giant dinosaurs may have cannibalized one another.
‘‘They’re the kind of marks that any big carnivore could have made, but T. rex was the only big carnivore in western North America 65 million years ago,’’ Nicholas R. Longrich of Yale University said in a statement.
T. rex was the only big carnivore in western North America 65 million years ago that was capable of making such large gouges, such as the ones seen here on a toe bone. – Photo by Nicholas Longrich/Yale University
Longrich and colleagues report their findings in Friday’s edition of the journal PLoS ONE.
They found 17 fossils with deep V-shaped gouges of a type identified as being made by T. rex. Of those, four were remains of T. rex themselves.
It seems likely the marks were made during scavenging from a dead dinosaur, the researchers said.
‘‘It does seem improbable that Tyrannosaurus routinely hunted full-grown members of its own species,’’ the researchers wrote.
However, they added, it is possible that combat led to casualties, with the dead becoming convenient sources of food for the victors. ‘‘Still, compelling evidence for predation in Tyrannosaurus remains elusive.’’
Longrich and colleagues note that ‘‘cannibalism is common in nature, particularly among large carnivores’’ such as bears, hyenas, large cats, Komodo dragons and alligators.
Co-authors are John Horner of Montana State University, Gregory Erickson of Florida State University and Philip Currie of the University of Alberta. ( Associated Press )
Dinosaur auction features fighting pair of skeletons - Natural history buffs with Tyrannosaurus-sized bank accounts got a chance to indulge themselves when a large collection of fully assembled, museum-quality dinosaur skeletons was put up for auction.
The featured stars of the Heritage Auctions bidding on Sunday were a “fighting pair” of dinosaur skeletons that sold to a museum for $2.75 million, and an enormous triceratops that fetched $657,250 from a private collector.
This handout image shows “The Fighting Pair, Allosaurus and Stegasaurus” that was sold to a museum for $2.75 million on June 12, 2011. – Reuters Photo
The Dallas auction included more than 200 items, including meteorites, minerals and other fossils.
The fighting dinosaurs — an allosaurus and a stegosaurus — were offered together because of their discovery in a Wyoming quarry with the jaw of the allosaurus wrapped around the leg of the stegosaurus, leading to speculation that the two were engaged in a predator-prey battle.
Heritage Auctions declined to disclose which museum picked up the pair, though the organization did say the museum was outside the United States.
“I’m ecstatic that ‘the fighting pair’ found such a great home,” David Herskowitz, director of natural history at Heritage Auctions, said in a statement.
“These are important and iconic Jurassic-era specimens, which science did not even know existed together at the same time, and now they will be going to a final destination where the public will get to enjoy them and where they will be of maximum benefit to science.”
Collectors and museum benefactors were able to bid in person and online.
Hundreds of people showed up at Dallas’ Fair Park to catch a glimpse of the rare and unusually large collection of dinosaur skeletons and other artifacts.
Paul Garner of Dallas came on Sunday with an entourage of family and friends.
“We heard about it from a friend, so we came to look,” the day before the auction, he said. “We came back for a second look and with better cameras.”
While some specimens were being offered for re-sale, the allosaurus and stegosaurus were on the market for the first time.
Paleontologist Henry Galiano, whose company unearthed the allosaurus and stegosaurus in Wyoming’s Dana Quarry in 2007, said the pair was put up for auction to raise money to continue research and the search for new specimens.
Dinosaur skeletons have held the public’s fascination since they were first put on display over 150 years ago. Searching for and excavating such fossils is still a tedious, labor-intensive process that has seen little technological advancement since the 19th century, Galiano said.
Yet, interest in the “bones business” is increasing, and there are more expeditions worldwide than ever before.
“I think it was probably the film ‘Jurassic Park’ that got the public really interested in dinosaurs,” Galiano said.
Interest was further spurred by the discovery of a Tyrannosaurus rex skeleton, now named Sue, in 1990, he said.
Sue was sold at auction in 1997 for $8.3 million to Chicago’s Field Museum of Natural History, Herskowitz said.
Dinosaur skeletons rarely fetch that much and are considered a relative bargain in the world of collectibles, he said. He said the triceratops skeleton was offered at an opening bid of $500,000.
“Fossils are cheap compared to fine art,” he told Reuters.
“It’s amazing the millions people will spend on fine art.” ( Reuters )
T-Rex's bite was 'three times greater than shark' - The Tyrannosaurus Rex had the most powerful bite of any creature ever to roam the Earth - up to three-and-a-half times greater than the Great White Shark, according to new research.
A man walks past a restored skeleton of a Tyrannosaurus Rex
The dinosaur could bring its jaws together with a remarkable force of up to 57,000 Newtons (13,000 lbs) - four times more than previous estimates.
Its performance surpasses that of all animals, both living and extinct, including today's great white shark, the most terrifying modern day creature which packs a 3,600 pound (1.8 tons) bite.
Musculoskeletal biologist Dr Karl Bates said: "Our results show T Rex had an extremely powerful bite making it one of the most dangerous predators to have roamed our planet."
His researchers at Liverpool University made computer models of T Rex's jaw and compared it with similar reconstructions of the skulls of another theropod dinosaur Allosaurus, an alligator and a human.
They found it clamped down on is prey with a crushing force up to almost fifty times more than a large African lion (1,235lbs).
Dr Bates said: "Models predict adult T. rex generated sustained bite forces of 35,000 (8,000lbs) to 57,000 Newtons at a single posterior tooth, by far the highest bite forces estimated for any terrestrial animal."
The study published in the Royal Society journal Biology Letters provides the first direct bite predictions and suggests T. rex probably had the most powerful bite of any terrestrial animal ever to have existed.
Results also suggest adult T. rex had a powerful bite in both absolute and relative terms for its body size, and that biting performance increased during growth, allowing it to kill and eat other big dinosaurs that were around at the time.
Dr Bates said: "The larger it grew the more it would have slowed down so its forearms got relatively smaller and its head bigger.
"This adds to evidence that it would have hunted and killed beasts that were even bigger than itself such as Triceratops and the armoured dinosaurs, possibly because it needed to prey on bigger animals to sustain itself."
He said the Nile crocodile's bite that has been measured at a force of 5,000 lbs (22,000 Newtons) is the closest living creature to it.
Then there is the Great White Shark but comparing a terrestrial animal with an aquatic one is "like chalk and cheese."
His team artificially scaled up the skulls of a human, alligator, a juvenile T Rex and Allosaurus to the size of an adult T Rex. In each case the bite forces increased but not to the level of the fully grown T Rex.
Dr Bates said: "Bite mechanics and feeding behaviour in Tyrannosaurus rex are controversial. Some contend a modest bite mechanically limited T. rex to scavenging, while others argue that high bite forces facilitated a predatory mode of life."
The researchers also found the juvenile T Rex has a relatively weaker bite than the adult suggesting feeding behaviour changed as it grew.
Juveniles possessed a lower, longer snouted skull than adult T. rex. Expansion of the skull with maturity potentially provided greater volume for jaw-closing.
Tyrannosaur body proportions changed appreciably during development and biomechanical analyses have provided strong evidence that young individuals were more athletic than adults.
With bite forces comparable to alligators and lions, combined with relatively long forelimbs and hindlimbs, juvenile T. rex appears well equipped to pursue and dispatch small to medium-sized prey.
Dr Bates said: "Forelimbs became significantly reduced in adults, and our results strongly suggest increasing importance of the skull in food procurement as compensation.
"Enhancement of an already highly competent biting apparatus during the exponential growth phase may be indicative of a change in feeding behaviour as T. rex reached adulthood.
"Living carnivores preying on large animals have relatively high bite forces, while carnivores preying on small prey have more moderate bite forces for their size, suggesting that bite force represents an important adaptation to differing feeding ecologies, at least throughout carnivoran evolution."
Attaining adult body sizes, combined with specialised jaw anatomy underpinning high mechanical performance, may have allowed adult T. rex to function as a 'large prey specialist', alleviating direct competition from smaller, more agile carnivores, including juvenile T. rex.
Dr Bates said: "The power of the T Rex jaw has been a much debated topic over the years.
"Scientists only have the skeleton to work with as muscle does not survive with the fossil so we often have to rely on statistical analysis or qualitative comparisons to living animals which differ greatly in size and shape from the giant enigmatic dinosaurs like T Rex.
"As these methods are somewhat indirect it can be difficult to get an objective insight into how dinosaurs might have functioned and what they may or may not have been capable of in life.
"To build on previous methods of analysis we took what we knew about T Rex rom its skeleton and built a computer model that incorporated the major anatomical and physiological factors that determine bite performance.
"We then asked the computer model to produce a bite so we could measure the speed and force of it directly. We compared this to other animals of smaller body mass and also scaled up smaller animals to the size of T rex to compare how powerful it was in relative terms."
Dr Bates added: "Ots unique musculoskeletal system will continue to fascinate scientists for years to come." ( telegraph.co.uk )
Tiny footprints found amid ancient dinosaur nests - Tiny footprints and fossil embryos at the oldest dinosaur nesting site ever found have revealed new details about how these ancient creatures reared their young, according to research published on Monday.
The nest belong to mid-sized dinosaurs from the Early Jurassic Period known as Massospondylus, which grew to four to six meters (13 to 20 feet) long as adults. Their eggs, however, are only six centimeters in diameter.
The traces left behind show that hatchlings stayed in the nest until they doubled in size, and that the young Massospondylus walked on four legs while young, but then likely stood upright on two legs as adults.
The analysis led by Canadian and South African researchers is based on findings at an excavation in Golden Gate Highlands National Park in South Africa, and is published in the Proceedings of the National Academy of Sciences.
An image provided by the University of Toronto shows a close-up of an embryonic skeleton of a Massospondylus from a clutch of eggs at the nesting site at the Golden Gate Highlands National Park, South Africa. Tiny footprints and fossil embryos at the oldest dinosaur nesting site ever found have revealed new details about how these ancient creatures reared their young, according to research. (AFP Photo/)
The fossils date to 190 million years ago, presenting the oldest known evidence of such behavior among dinosaurs.
The first fossilized dinosaur embryo was in Golden Gate in 1976, and the first details about unhatched dinosaurs found inside fossilized eggs at the site were published to international fanfare in 2005.
At least 10 nests have now been uncovered at various levels, each holding as many as 34 eggs in close-knit clutches.
"The eggs, embryos, and nests come from the rocks of a nearly vertical road cut only 25 meters (yards) long," said paleontologist Robert Reisz, a professor of biology at University of Toronto Mississauga.
"Even so, we found 10 nests, suggesting that there are a lot more in the cliff, still covered by tons of rock. We predict that many more nests will be eroded out in time as natural weathering processes continue."
Researchers believe the layout of the nests suggest that the site was returned to repeatedly by the dinosaur mothers, who laid eggs together as a group and carefully organized their eggs in their nests.
"Even though the fossil record of dinosaurs is extensive, we actually have very little fossil information about their reproductive biology, particularly for early dinosaurs," said David Evans, associate curator, Vertebrate Palaeontology at the Royal Ontario Museum.
"This amazing series of 190 million year old nests gives us the first detailed look at dinosaur reproduction early in their evolutionary history, and documents the antiquity of nesting strategies that are only known much later in the dinosaur record." ( AFP )
Oldest Dinosaur 'Nursery' Discovered - Tiny prints from baby dinosaurs dot the oldest dino nesting site found to date, a 190-million-year-old nursery in South Africa, researchers said.
The hatchery and the baby footprints uncovered there are significant clues about the evolution of complex family behaviors in early dinosaurs, providing the oldest-known evidence that dinosaur hatchlings remained at nests long enough to at least double in size.
The newly unearthed clutches of eggs, many with embryos inside, belonged to the plant-eating dinosaur Massospondylus, a prosauropod, or predecessor of the largest animals to ever walk the Earth, long-necked sauropods such as Brachiosaurus.
How to unearth a dinosaur egg
The international team of researchers conducted their excavation in the Golden Gate Highlands National Park in South Africa. The nesting ground, now largely covered in reddish-brown muddy siltstone, predates previously known nesting sites by 100 million years.
"The eggs, embryos and nests come from the rocks of a nearly vertical road cut only 25 meters (82 feet) long," said researcher Robert Reisz, a paleontologist at the University of Toronto at Mississauga. "Even so, we found 10 nests, suggesting that there are a lot more in the cliff, still covered by tons of rock. We predict that many more nests will be eroded out in time as natural weathering processes continue."
The eggs and nests proved difficult to unearth because the eggshells are extremely delicate at less than 100 microns in thickness, or less than the width of a human hair, making it easy to inadvertently destroy them. "We literally spent days and days searching for the eggs and nests, spending most of our time on our hands and knees, but once we were able to recognize what to look for, we found four nests within 10 minutes," Reisz told LiveScience.
The nests unearthed to date each held up to 34 round eggs in tight clusters. The skeletal remains of the mothers suggest they were about 20 feet (6 meters) long, while their eggs were only about 2.3 to 2.7 inches (6 to 7 centimeters) wide. The mothers carefully arranged these eggs, the researchers say, basing this on the high level of organization of the nests and eggs.
Dinosaur day care
From the fine-grained nature of the sediments holding the eggs, the researchers think the nests were built near a lake or a slow-moving river. "The fact that the nests are relatively close to water, and the soil was moist, suggests that there was lots of vegetation," Reisz said. This likely made the area attractive to these herbivores.
And the site seemed to be a popular one for dino day care, as the nests were found in at least three distinct layers of rock within the excavation, each indicating a different point in time. In fact, the researchers suggest the dinosaur moms likely returned repeatedly to the site. Also, the fact that multiple nests were found within the same layers — and thus were laid at about the same time — reveals the dinosaurs likely gathered in groups to lay their eggs, the oldest evidence of such behavior in the fossil record.
"Even though the fossil record of dinosaurs is extensive, we actually have very little fossil information about their reproductive biology, particularly for early dinosaurs," said researcher David Evans, associate curator of vertebrate palaeontology at the Royal Ontario Museum in Canada. "This amazing series of 190-million-year-old nests gives us the first detailed look at dinosaur reproduction early in their evolutionary history, and documents the antiquity of nesting strategies that are only known much later in the dinosaur record."
The researchers are now slowly uncovering embryos within these eggs. They have embryos in several different stages of development, "allowing us to do actual comparisons between them," Reisz said. "The preservation is exquisite." ( LiveScience.com )
Oldest Known Dinosaur Nesting Site Found -- Researchers who found the earliest known dinosaur nesting site say it offers significant clues about the evolution of complex reproductive behavior in early dinosaurs.
The 190-million-year-old site in South Africa is 100 million years older than previously known nesting sites. It contains clutches of eggs of the prosauropod dinosaur Massospondylus, a relative of the giant, long-necked sauropods of the Jurassic and Cretaceous periods. Many of the eggs contain embryos.
There are also tiny dinosaur footprints, which provide the oldest known evidence that hatchlings remained at the nesting site long enough to at least double in size.
At least 10 nests, each with up to 34 round eggs in tightly clustered clutches, have been found at several ground levels at the site. The fact that there are nests at different levels in the sediment indicates that the dinosaurs returned repeatedly to the site and likely gathered in groups to lay their eggs.
This is the oldest known evidence of such behavior in the fossil record, according to Robert Reisz, a paleontologist and professor of biology at University of Toronto.
The mothers were 6 meters long and the eggs were about 6 to 7 centimeters in diameter. The highly organized nature of the nests suggests that the mothers carefully arranged the eggs after they laid them.
"The eggs, embryos and nests come from the rocks of a nearly vertical road cut only 25 meters long," Reisz said in a university news release. "Even so, we found ten nests, suggesting that there are a lot more in the cliff, still covered by tons of rock. We predict that many more nests will be eroded out in time as natural weathering processes continue." ( HealthDay News )
New species of dinosaur discovered in museum basement - Paleontologists are used to digging deep for dinosaur remains--but to turn up a newly discovered dinosaur species, they had to dig no deeper than the basement of a London museum.
London's Natural History Museum is a place of constant discovery--for school field trips and science buffs. But this particular discovery, officially known as Spinops sternbergorum, took place in a storage area in the museum's basement.
"I knew right away that these fossils were something unusual, and it was very exciting to learn about their convoluted history," said Dr Andrew Farke, who led the research team.
"Here we have not just one, but multiple individuals of the same species, so we're confident that it's not just an odd example of a previously known species."
The Spinops is about the size of a large bull, with a beak shaped mouth, weighing in at 1 ton and measuring nearly 20 feet in length.
The remains of the Spinops, which comes from the same herbivore family as the Triceratops, were actually discovered in a quarry known as the "bone bed" in Alberta, Canada in 1916. However, A. Smith Woodward, the former Museum Keeper of Geology didn't think much of the find, describing it as "nothing but rubbish" and the remains were simply transferred into storage.
'This discovery demonstrates that new dinosaurs are found in museum collections and laboratories almost as frequently as in the field,' said Dr Paul Barrett, palaeontologist at the Natural History Museum.
It wasn't until Dr. Farke and his team reexamined the remains that they realized a new species of dinosaur had been rediscovered after nearly 100 years.
"This discovery is significant because it adds to our knowledge of horned dinosaur diversity in the Late Cretaceous," said Dr. Michael Ryan, curator of vertebrate paleontology at The Cleveland Museum of Natural History. "Natural selection appears to have acted exclusively on the ornamentation on the head in these dinosaurs such that new species are appearing at a very high rate in this group—less than one-half million years." ( yahoo.com )
Dinosaur Footprints Discovered in Arkansas – Researchers were studying new fossilized dinosaur tracks Thursday, after they discovered a field of 120 million-year-old footprints in southwestern Arkansas.
The field, which is on private property, covers an area of about two football fields and contains fossilized tracks of several species that have never been previously documented in Arkansas before, including one set from a three-toed dinosaur, measuring two feet (61 centimeters) long by a foot (30 centimeters) wide.
University of Arkansas researchers are examining dinosaur tracks found in southwest Arkansas. They made a plaster casting of this track, which is believed to have belonged to a giant carnivore called Acrocanthosaurus atokensis that lived during the Early Cretaceous.
The researchers, from the University of Arkansas, Fayetteville, believe the three-toed print may belong to Acrocanthosaurus atokensis, one of the largest predators to ever walk the earth.
The site also contains the giant prints of sauropods -- large, long-necked, plant-eating dinosaurs such as Pleurocoelus and Paluxysaurus.
"The quality of the tracks and the length of the track ways make this an important site," said Stephen Boss, who led the National Science Foundation-funded project.
Scientists said the discovery will help them learn about the creatures and climate of the Early Cretaceous period, 115 to 120 million years ago.
"Through tracks, we can learn all sorts of things about dinosaur biomechanics and behavior," said Brian Platt of the University of Kansas. "Dinosaur bones can be dragged away by animals or swept out to sea. But we know that about 120 million years ago, dinosaurs walked right through here." ( foxnews.com )
New dinosaur tracks found in US state - Researchers at the University of Arkansas are studying a new field of fossilized dinosaur tracks, including one set that appears to be from a large three-toed predator, the university said Wednesday.
The tracks were found on private land in southwest Arkansas and provide a window into the life forms that roamed the area as long as 120 million years ago during the Early Cretaceous period.
“The quality of the tracks and the length of the trackways make this an important site,” said Stephen K. Boss, who led the project.
The research effort is funded by a grant from the National Science Foundation.
Based on the rock in which the footprints were found, researchers have a good idea of what the climate would have been like, Boss said.
Tracks from a three-toed dinosaur that researchers are studying in Southwest Arkansas are seen in this July 2011 photo provided by the University of Arkansas. (AP)
“Picture an environment much like that of the shores of the Persian Gulf today. The air temperature was hot. The water was shallow and very salty,” Boss said. “It was a harsh environment. We’re not sure what the animals were doing here, but clearly they were here in some abundance.”
Some of the tracks in the field have not been documented before in Arkansas. The researchers’ work will expand knowledge about dinosaurs that roamed the area and the climate during the period.
The tracks from the three-toed dinosaur are about 2 feet (0.6 meters) long by 1 foot (0.3 meter) wide and likely are from Acrocanthosaurus atokensis, one of the largest predators ever known. There are also prints from sauropods, large, long-necked plant-eating dinosaurs. Other sauropod tracks have been found in the state, including at a site near Nashville, also in the state’s southwest.
“Through tracks, we can learn all sorts things about dinosaur biomechanics and behavior,” said University of Kansas researcher Brian Platt, who is taking part in the program. “Dinosaur bones can be dragged away by animals or swept out to sea. But we know that about 120 million years ago, dinosaurs walked right through here.”
The grant from the National Science Foundation enabled a team of researchers to spend two weeks studying the site. They used traditional tools, including hammers, chisels and brooms, but also cutting-edge technology to record images, take measurements and map the site.
Rock samples from the site can also shed light on the conditions under which the dinosaurs lived.
“Because we see footprints here, we know that this surface was at one time exposed to the elements,” said Celina Suarez, a postdoctoral researcher at Boise State University who will be joining the faculty at the University of Arkansas in the fall of 2012.
Researchers can calculate how much rain fell and how much moisture evaporated. Using data from this site and others, scientists can learn more about the climate in general and work to predict the planet’s future climate.
“This site will add to the knowledge of both the animals and climate of the Early Cretaceous,” Boss said. “Scientists will be studying these data for many years.” ( arabnews.com )
