Ancestor of T rex found in China
Tyrannosaurus rex may have had much smaller ancestors
Fossils found in China may give clues to the evolution of Tyrannosaurus rex.
Uncovered near the city of Jiayuguan, the fossil finds come from a novel tyrannosaur dubbed Xiongguanlong baimoensis.
The fossils date from the middle of the Cretaceous period, and may be a “missing link”, tying the familiar big T rex to its much smaller ancestors.
The fossils show early signs of the features that became pronounced with later tyrannosaurs.
Paleontological knowledge about the family of dinosaurs known as tyrannosaurs is based around two distinct groups of fossils from different parts of the Cretaceous period, which ran from approximately 145 to 65 million years ago.
One group dates from an early part of the period, the Barremian, and the other is from tens of millions of years later.
Before now it has been hard for palaeontologists to trace the lineage from one group to the other.
“We’ve got a 40-50 million year gap in which we have very little fossil record,” said Peter Makovicky, associate curator at the Field Museum in Chicago, who helped to lead the US/Chinese team that uncovered the fossil.
Hadrosaurs – duck-billed dinosaurs – spread rapidly in the late Cretaceous
But, he said, X baimoensis was a “nice link” between those two groups.
“We’re filling in that part of the fossil record,” he said.
Writing in the Royal Society’s journal Proceedings B, Dr Makovicky and colleagues suggest that X baimoensis is a “phylogenetic, morphological, and temporal link” between the two distinct groups of tyrannosaurs.
The fossil has some hallmarks of large tyrannosaurs such as a boxy skull, reinforced temple bones to support large jaw muscles, modified front nipping teeth and a stronger spine to support a large head.
But it also shows features absent from older tyrannosaurs, such as a long thin snout.
An adult would have stood about 1.5m tall at the hip and weighed about 270kg. By contrast, an adult T rex was about 4m tall at the hip and weighed more than 5 tonnes.
The same edition of Proceedings B features papers about two other sets of dinosaur fossils.
One discovery was made in China by many of the palaeontologists who found the tyrannosaur. The samples found in the Yujingzi Basin came from a dinosaur that resembled the modern ostrich.
While many of these ornithomimosaurs have been found before, analysis of the bones of the new species, dubbed Beishanlong grandis, suggest it was one of the biggest.
The specimen found by the palaeontologists was thought to be 6m tall and weigh about 626kg.
Alongside in Proceedings B was work on the remains of a duck-billed dinosaur found in Uzbekistan called Levnesovia transoxiana.
Analysis of the fossils, by Hans-Dieter Sues of the Smithsonian in Washington and Alexander Averianov of the Russian Academy of Sciences, may shed light on the waves of expansion hadrosaurs undertook during the late Cretaceous.
FOXNews – 22-apr-2009
A Tyrannosaurus rex ancestor and an ostrich-mimic have emerged as two new dinosaur species found among a treasure trove of skeletons in China’s Gobi Desert. …
Phil Bell holding a vertebra of a 70-million-year-old Saurolophus.
October 21, 2008 – Edmonton-Contrary to popular belief, polar dinosaurs may not have traveled nearly as far as originally thought when making their bi-annual migration.
University of Alberta researchers Phil Bell and Eric Snively have suggested that while some dinosaurs may have migrated during the winter season, their range was significantly less than previously thought, which means their treks were shorter. Bell and Snively’s findings were recently published in Alcheringa: An Australasian Journal of Paleontology.
The idea that these animals may have travelled distances nine times further than mule deer or four times those of wildebeest would have made them the greatest migrators in history. “There are strong opinions regarding dinosaur migration, but we decided to take a different approach, looking at variables such as energy requirements,” said Bell. Their research led them to suggest that migrating dinosaurs could have travelled up to 3,000 kilometres in a round trip-lasting perhaps up to six months-half of the distance suggested previously.
According to Bell, the notion of migrating polar dinosaurs is not new; however, previously-held beliefs were that the animals followed the centrally shifting sunlight, or latitudinal “sun line,” as part of their migration and would travel as far as 30 degrees of latitude, or 3,200 kilometres, in order to survive. Given their size and physiology, Bell and Snively have concluded that dinosaurs would have been incapable of sustaining the effort needed to make the trip. “When we looked at the energy requirements needed to support a three-tonne Edmontosaurus over this distance, we found it would have to be as energy efficient as a bird. No land animal travels that far today,” said Bell.
Bell does not dispute the evidence of migration and points to discoveries of large bone beds as evidence that many dinosaurs also traveled. In order to sustain the herd, “it seemed to make sense that they would be moving to and from the poles,” he said.
While this view of migration is feasible for some species of polar dinosaurs, it does not hold for all, Bell noted. “Many types of dinosaurs were surviving in polar latitudes at the time, and getting along quite fine,” said Bell. “They were not physically able to remove themselves from the environment for a variety of reasons and had to adapt to the cold, dark winters just as the rest of us mammals do today.”
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Authors: Phil R. Bell; Eric Snively
Cretaceous polar dinosaur faunas were taxonomically diverse, which suggests varied strategies for coping with the climatic stress of high latitudes. Some polar dinosaurs, particularly larger taxa such as the duckbill Edmontosaurus Lambe, 1917, were biomechanically and energetically capable of migrating over long distances, up to 2600 km. However, current evidence strongly suggests many polar dinosaurs (including sauropods, large and small theropods, and ankylosaurs of New Zealand) overwintered in preference to migration. Certain groups also appear more predisposed to overwintering based on their physical inability (related to biomechanics, natural history, or absolute size) to migrate, such as ankylosaurs and many small taxa, including hypsilophodontids and troodontids. Low-nutrient subsistence is found to be the best overwintering method overall, although the likelihood that other taxa employed alternative means remains plausible. Despite wide distribution of some genera, species-level identification is required to assess the applicability of such distributions to migration distances. Presently, such resolution is not available or contradicts the migration hypothesis.
|Keywords: Alaska; Albian; Aptian; Australia; Campanian; Cretaceous; Dinosaur Cove; endothermy; migration; New Zealand; polar dinosaurs
Fossil find puts river on scientific cutting edge
Discovery near Pickstown ‘special’
PICKSTOWN – Jim Martin probed the cliffside soil with a blue-handled rock hammer, pounding at times, then using the hammer’s chiseled end to scrape at a fine-grained, dark layer.
“There it is, there we go,” he said. “That’s exactly what we’re looking for.”
And with that, he picked up a handful of dark, gritty material from a 2-inch band just above the layer of hard shale that used to be the bottom of a great inland seaway covering what now is South Dakota.
Martin, executive director of the Museum of Geology at the South Dakota School of Mines in Rapid City, was on a “CSI”-style investigation on the shores of Lake Francis Case, in a bay across from the Fort Randall Dam. He was trying to find out what killed one short-necked plesiosaur, a 25-foot marine reptile that zoomed through the water with the aid of four paddle-like flippers while devouring most anything in its path.
“Think of it as the Loch Ness monster, although that’s simplistic,” Martin said. “The finest fisherman ever to live. It was agile, fast – it would have done well with just its front flippers, moving like a seal or a penguin – but this one had a super-charger on its rear end.”
The fossilized plesiosaur, only the second nearly complete skeleton ever found in the state, was discovered in July at Lake Francis Case by 11-year-old Devon Zimmerman of Sioux City, Iowa. Its discovery extends not only science’s knowledge of the beast but also of events that shook the Great Plains landscape of the late Cretaceous period, sometime between 72 million and 74 million years ago.
“I was out walking on the shore, tossing rocks,” Devon said. “I thought it was something, something really cool.”
His mother, DeeAnn Zimmerman, added: “He found it and said it looked like a spine. His dad (Duane) said it was probably a piece of wood. Really, we just sort of forgot about it. Then we went back and looked at it and said, ‘Oh, no, that really is a fossil.’ And we went to the visitors’ center to report it.”
Cody Wilson, lake manager with the U.S. Corps of Engineers in Pickstown, said the Zimmermans did the right thing. Instead of chipping it out and trying to take some of it away to sell on eBay, the Zimmermans preserved the find for the public, for science, for the rest of history, Wilson said.
When informed of the find, Martin was more than willing to drive from Rapid City to check it out.
“I think I was in the car the next day,” he said.
The fossilized remains curve in the rock, the long-billed skull facing away from shore. Bits of scale and small bones filled the area where the reptile’s fleshy stomach would have been.
“Something killed this critter pretty fast,” Martin said. “And that’s the thing about this particular specimen; we have its last supper in its stomach, the fossil remains of three different kinds of fish.”
The plesiosaur was found in a layer of silicified shale, a hard rock layer that’s like quartz.
“Hit it with a hammer, and it’ll bounce back,” Martin said. “We had to go back and get the jackhammer and saw.”
Volunteers – including Devon Zimmerman – carefully cut their way around the fossil, packed the rock in plaster and trucked it back to Rapid City. There, another volunteer will work with a small pneumatic air device to slowly separate the fossil from the shale.
“It’ll take another five years to get it out of the stone,” Martin said. “But I can wait. Plesiosaurs have been found on every continent, but this one’s special. We’ve found skulls, bones, but to get 60 percent of one fossil, I’d have been happy with 20 percent. And we could be talking about a new critter here.”
That’s what brought Martin back in late September to Lake Francis Case, to try to figure out what caused this plesiosaur to expire so suddenly, and to be preserved almost instantly after death.
The great inland seaway of the Cretaceous stretched from the Gulf of Mexico northwest toward what now is northern Alaska. The sea was as deep as 700 feet near the Gulf, and probably about 200 feet deep over South Dakota, Martin said.
It was rich with a variety of Mesozoic marine reptiles, including plesiosaurs, giant marine turtles and mosasaurs – basically a crocodile with paddles. Mosasaurs, called the tyrannosaurs of the sea, are the most commonly preserved marine reptiles in the state.
“Plesiosaurs – the pliosaurid, or short-necked version – is a different matter,” Martin said. “I wish people would find more so I could have a bigger sampling. But two in a lifetime – I’ll take it.”
The handful of dirt in his hand was compressed ash, and when it was deposited across the inland seaway, it settled into a layer that was more than 2 feet thick.
Above that layer, Martin pointed to layer of sand, and then a yellowish, lumpy layer filled with balls of pumice. Both the ash and pumice suggest a volcanic event.
“I would say this plesiosaur died during the Manson Impact,” Martin said.
The Manson Impact refers to a meteorite that struck what now is Pocahontas County, Iowa. Buried 100 to 300 feet below the town of Manson is the geologic record of the impact, which struck with the force of 10 trillion tons of TNT, said Ray Anderson, with the Iowa Department of Natural Resources.
The stony meteorite probably weighed about 10 billion tons, and its impact instantly ignited everything within 150 miles, toppled trees up to 300 miles away and most certainly killed every animal within 650 miles.
“Basically, this thing came up for air and got a lung full of hot glass shards,” Martin said. “And as it started to sink, choking, it got rolled in a giant wave. A tsunami, if you will, that swept across the seaway all the way from the impact crater in Iowa. Pretty much the most catastrophic day you could have.”
To be sure, Martin took samples of each layer, which he’ll study and date to confirm his hypothesis.
If it turns out to be a new species, there’s the distinct possibility that Martin will name it after Devon. Martin named the first nearly complete plesiosaur fossil found – a new species that dates back to 80 million years ago – after its finder, Paul Neumiller of Bonesteel.
“That would be really awesome,” Devon said.
Reach Thom Gabrukiewicz at 331-2320.
source (with video): http://www.argusleader.com/apps/pbcs.dll/article?AID=/20081011/NEWS/810110326/1001
Well-Preserved Dinosaur Guts Give Insight Into Prehistoric Diet
Thursday, September 25, 2008
An analysis of the gut contents from an exceptionally well-preserved juvenile dinosaur fossil suggests that the hadrosaur’s last meal included plenty of well-chewed leaves digested into tiny bits.
The fossil, Brachylophosaurus canadensis aka “Leonardo,” is the second well-substantiated case in which the gut contents of a plant-eating dinosaur have been revealed, said Justin S. Tweet, who was a graduate student at the University of Colorado at Boulder when he studied the fossil with colleagues there including paleontologist Karen Chin.
The dino, found in what geologists call the Judith River Formation, in Montana, will go on display to the public Friday at the Houston Museum of Natural Science’s “Dinosaur Mummy CSA: Cretaceous Science Investigation” exhibition.
“Our interpretation suggests that the subadult Judith River Formation brachylophosaur had a leaf-dominated diet shortly before its death,” the authors write in the September issue of PALAIOS, the journal of the Society for Sedimentary Geology.
Skin and scales
Leonardo is a 77-million-year-old duckbilled dinosaur whose remains are covered with patterned fossilized skin. The specimen has given scientists a rare peek inside a dinosaur. Digital technology and X-ray scans, some of which were conducted at NASA Johnson Space Center’s Ellington Field facility in Texas, has helped paleontologists reconstruct what Leonardo looked like in life, what it ate, its muscle mass and its limb movements.
An analysis of pollen found in the specimen’s gut region revealed a variety of plants, including ferns, conifers and flowering plants. Although the pollen could have been ingested when the dinosaur drank water, the tiny leaf bits, under 5 millimeters (a quarter-inch) in length, indicate that Leonardo was a big browser of plants, Chin said.
Hadrosaurs were certainly capable of processing food into tiny bits in part with their continually replacing teeth and grinding jaws.
The tricky part with the analysis was building a case that the plant matter found inside the gut came from the dinosaur’s last meal, not from material that penetrated the body or flowed into the area after death. The case was helped by the fact that Leonardo was buried quickly and undisturbed by scavengers, and its body cavity appears to be undisturbed. At least 12 percent of the gut contents in the carcass included organic matter, such as leaves. The rest was clay and grit. Some of the inorganic stuff probably flowed into the body after death, Tweet said.
Overall, the most exciting part of the research was working with material that could actually be gut contents, Tweet said.
“This is very rare for dinosaurs, where we usually have to settle for generalizations of feeding behavior based on skull anatomy,” he told LiveScience.
The research was funded by grants through the University of Colorado and its Museum of Natural History and a Geological Society of American Graduate Student Grant.
Houston Museum of Natural Science Curator of Paleontology Robert T. Bakker, one of the first scientists to work on the fossil, said that duckbill dinosaurs like Leonardo had large bills and jaws full of tiny teeth, about 800 of them, that ground and chopped tough plants and plant parts, including conifer needles, bark and twigs, like a “cranial Cuisinart.”
The contents of the gastrointestinal tract then were processed by digestive juices and gut microbes.
Leonardo has a pebbly skin texture, like the lower leg of an ostrich or another big bird, Bakker said, but on the front of Leonardo’s ankle and shin, the skin becomes very thick like armor which helped it move through the underbrush.
The fossil was discovered in the summer of 2000 during an expedition to a cattle ranch about 15 miles north of Malta, Mont. Leonardo was named after graffiti found on a nearby rock that read: “Leonard Webb loves Geneva Jordan 1916.”
The Houston exhibition will also feature an icthyosaur “mummy,” which has contents of her intestines and four babies preserved inside her body, and the only mummified Triceratops skin ever found. The exhibition’s opening was delayed a week as a result of conditions and power losses in the Houston area after Hurricane Ike, including five days without primary power at the museum. Leonardo and other exhibition specimens were unharmed, a museum spokeswoman said.
• Click here to visit FOXNews.com’s Evolution & Paleontology Center.
Probable Gut Contents Within A Specimen Of Brachylophosaurus Canadensis (Dinosauria: Hadrosauridae) From the Upper Cretaceous Judith River Formation Of Montana
Justin S. Tweet, Karen Chin, Dennis R. Braman, and Nate L. Murphy
PALAIOS 2008 23: 624-635. [Abstract] [Full Text] [Figures Only] [PDF]
Abstract – An exceptionally preserved subadult specimen (JRF 115H) of a hadrosaurid, Brachylophosaurus canadensis, from the Judith River Formation near Malta, Montana, contains abundant plant fragments concentrated within the body cavity. We examined the taphonomy of the carcass and analyzed the gut-region material to test whether the organic remains represent fossilized gut contents. The dinosaur was buried in a fluvial channel setting, and the excellent articulation, integument impressions, and lack of scavenging indicate rapid burial. The organic material occupies a volume of at least 5750 cm3, and comparable material is not found outside the carcass. The carcass contents include about 63% clay, about 16% undetermined matrix, about 12% organic matter, and about 9% larger inorganic clasts—mostly 50–100 µm quartz grains. Most of the organics appear to be mm-scale leaf fragments. The most parsimonious explanation for the presence and composition of the gut-region material is that much of the plant fossils represent reworked brachylophosaur ingesta influenced by flowing water that entered through openings in the carcass and introduced clay. The evidence strongly suggests that the hadrosaurid ate significant quantities of leaves and processed them into small pieces. This study provides baseline information for analyzing other cases of putative gut contents in herbivorous dinosaurs.
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Oldest Gecko Fossil Ever Found, Entombed In Amber
ScienceDaily (Sep. 3, 2008) — Scientists from Oregon State University and the Natural History Museum in London have announced the discovery of the oldest known fossil of a gecko, with body parts that are forever preserved in life-like form after 100 million years of being entombed in amber.
Due to the remarkable preservative power of being embalmed in amber, the tiny foot of this ancient lizard still shows the tiny “lamellae,” or sticky toe hairs, that to this day give modern geckos their unusual ability to cling to surfaces or run across a ceiling. Research programs around the world have tried to mimic this bizarre adhesive capability, with limited success.
This gecko’s running days are over, however, as only the foot, toes and part of a tail are left in the stone. The rest might have become lunch for a small dinosaur or other predator during an ancient fight in the tropical forests of Myanmar during the Lower Cretaceous Period, from 97 million to 110 million years ago.
The find is at least 40 million years older than the oldest known gecko fossil, shedding additional light on the evolution and history of these ancient lizards that scampered among the feet of giant dinosaurs then and still are common in tropical or sub-tropical regions all over the world.
The findings were just published in Zootaxa, a professional journal.
“It’s the unusual toe pads and clinging ability of some geckos that make them such a fascinating group of animals, so we were very fortunate to find such a well-preserved foot in this fossil specimen,” said George Poinar, Jr., a courtesy professor at OSU and one of the world’s leading experts on insects, plants and other life forms trapped in amber, a semi-precious stone that begins as tree sap.
“There’s a gecko society, gecko clubs, just a lot of interest in these animals because of their unusual characteristics,” Poinar said. “So there are a lot of people pretty excited about this.”
Based on the number of lamellae found on its toe pads, this gecko was probably a very small juvenile of what would have become a comparatively large adult, possibly up to a foot long, the researchers say. Modern geckos get no more than about 16 inches long, although it’s possible there were larger species millions of years ago. The juvenile gecko found in the fossiljuvenile gecko found in the fossil was less than an inch in length when it died – possibly by being eaten or attacked, since only partial remains were found.
The discovery has been announced as a new genus and species of gecko, now extinct, and has been named Cretaceogekko. It had a striped pattern that probably served as camouflage.
There are more than 1,200 species of geckos in the world today , common in warm or tropical regions, including parts of the southern United States. They are frequently kept as pets, and often are welcome in the homes of some tropical residents because they help control insects. Some are very colorful. They use long tongues to lick, clean and moisturize their eyes.
“Geckos are territorial, and when I lived in Africa in the early 1980s we used to have them in our house,” Poinar said. “They are pretty friendly and don’t bother humans. Certain individuals would move into the house, we’d give them names, and they would run around the house, catch mosquitoes, help control bugs. They would crawl across the ceiling and look down at you.”
The new study provides evidence that geckos were definitely in Asia by 100 million years ago, and had already evolved their bizarre foot structure at that time. The amber fossil was mined in the Hukawng Valley in Myanmar, and during its life the gecko probably lived in a moist, tropical forest with ample opportunities for climbing.
The ability of geckos to walk on vertical walls or even upside down is due to the presence of thousands of “setae” on their toes, very tiny, hairlike structures that have tips which attach to surfaces by van der Walls forces. It’s a type of incredibly strong, dry adhesion shared by virtually no other group of animals.
It’s not known exactly how old this group of animals is, and when they evolved their adhesive toe pads. However, the new study makes it clear that this ability was in place at least 100 million years ago, in nature. Modern research programs still have not been able to completely duplicate it.
Scientists at the University of California at Berkeley reported earlier this year that they have developed a new “anti-sliding” adhesive that they said was the closest man-made material yet to mimic the ability of geckos – they think it might help a robot climb up the side of walls. A research team at the Massachusetts Institute of Technology this year created a waterproof adhesive bandage inspired by geckos, that may some day be used in surgery. And of course, geckos have become an advertising icon for the insurance company Geico.
This study is just one of many in which Poinar and colleagues have used the unusual characteristics of amber to study ancient life forms and develop information on the ecology of ancient ecosystems.
As a stone that first begins to form as sap oozing from a tree, amber can trap small insects or other life forms and preserve them in near-perfect detail for observation millions of years later.
Is the 87-million-year-old praying mantis recently found encased in amber in Japan a “missing link” between mantises from the Cretaceous period and modern-day insects?
It is a rare find indeed and its true significance is still to be deciphered.
Discovered in January of this year by Kazuhisa Sasaki, director of the Kuji Amber Museum, the fossil mantis measures 0.5 inch (1.4 centimeters) from its antennae to the tip of its abdomen.
It was found buried more than six feet below the surface of an amber mine in a part of Japan that is famous for producing large amounts of amber, the northeastern Iwate Prefecture.
“I found it in a deposit that had lots of other insects—ancient flies, bees, and cockroaches—but this was the only praying mantis” said Sasaki.
The fossil mantis is partially well preserved, although its wings and abdomen are badly crushed.
According to Kyoichiro Ueda, executive curator of the Kitakyushu Museum of Natural History, it is the oldest mantis fossil ever found in Japan and only one of seven in the entire world from the Cretaceous Period.
Even more unique is the fact that this mantis is different from the other six, in that it has two spines protruding from its femur and it has mysterious, tiny hairs on its forelegs.
No mantis from this particular time period has ever been found with spines, although modern mantises have five or six on their forelegs, which help them catch prey.
“The years of the late Cretaceous period were a kind of transition phase between the ancient and modern worlds, and this fossil displays many intermediate elements between the two eras” said Ueda.
Time alone will reveal the significance of this important find.