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Post by brobear on Aug 27, 2021 4:36:45 GMT -5
www.sci-news.com/paleontology/carnosaurs-apex-scavengers-09999.html Carnosaurs were Apex Scavengers, New Research Suggests. Carnosaurs may have been terrestrial analogues of vultures, and not predators, according to a new study published in the journal Ecological Modelling. Carnosaurs are members of Carnosauria, a large group of carnivorous dinosaurs that lived during the Jurassic and Cretaceous periods. These creatures first appeared in the Middle Jurassic epoch, around 176 million years ago, and became extinct around 66 million years ago. The most famous and best understood representatives of this group are members of the North American genus Allosaurus. “Allosaurs were contemporary in time and space with some of the largest herbivorous dinosaurs ever recorded,” said Portland State University paleontologists Cameron Pahl and Luis Ruedas. “These would have included well-known dinosaurs such as Camarasaurus, Barosaurus, Apatosaurus, Diplodocus, Brontosaurus, Supersaurus, and Brachiosaurus.” “Brachiosaurus in particular once was considered the largest land animal to have ever lived and could have been up to 21 m (70 feet) long and 64 tons in weight.” “Supersaurus were over 33.5 m (110 feet) in length and weighed up to 40 tons.” “If these giant dinosaurs died primarily of natural causes, such as disease, starvation, and exhaustion, as is typical of many modern herbivore populations, their carcasses would have been plentiful enough to sustain viable populations of allosaurs even without these undertaking any predatory behaviors.” The researchers supported their hypothesis with a robust agent-based model, which simulated the relationship between carrion resources (carcasses) present in the Late Jurassic Morrison Formation and the food energy requirements of allosaurs. They further examined morphological attributes of allosaur skulls, including the extent of binocular vision in predators versus scavengers, as well as ecological data from fossils, such as relative population numbers in predators, herbivores, and scavengers. The relative fragility of the skull and dentition of allosaurs had already cast doubt on these dinosaurs being predators. In addition to this shortcoming, allosaurs did not have the binocular vision required to be a successful predator: it was only 30% that of Tyrannosaurus rex, and 15% that of a modern lion’s. “Our results may explain why carnosaurs like allosaurs did not evolve powerful bite forces, binocular vision, or advanced cursorial adaptations,” the scientists said. “Given the enormous supply of sauropod carrion, they were under no resource-based selective pressure to overpower prey and may have evolved as terrestrial vulture analogues.” “This also may explain why the absence of sauropods in certain environments led to more obvious predatory adaptations in theropods such as tyrannosaurs.” “Tyrannosaurs may have been forced to meet their energy budgets by hunting, because non-sauropod carrion production was too low to support them passively.” *Allosaurus - Carnosauria / Tyrannosaurus - Coelurosauria.
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Post by brobear on Aug 28, 2021 9:16:43 GMT -5
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Post by brobear on Aug 29, 2021 1:40:42 GMT -5
www.cbc.ca/news/science/pregnant-t-rex-1.3492716?fbclid=IwAR0EpguwLZLPDMNnpiLG-2HjL1cwn7oxgpv3IflMqOXBaHqW4T8_Hb7C6lk 'Pregnant' T. rex discovery confirmed. Chemical test for medullary bone, found during egg laying, positively identifies females. A Tyrannosaurus rex that died 68 million years ago in what is now Montana was "pregnant" at the time, U.S. researchers have confirmed. Chemical tests confirmed the T. rex's thigh bone contained medullary bone — a special kind of bone that is expected to only form when a dinosaur is laying eggs or about to lay eggs. Because birds and meat-eating dinosaurs such as T. rex are closely related, scientists had predicted that medullary bone might one day be found in dinosaurs. Schweitzer added that knowing that the dinosaur is female could allow researchers to identify "female" traits in other parts of the body that are visible all the time, even when the dinosaurs isn't about to lay eggs. That, in turn, could tell scientists a lot more about things such as the sex ratios in the population.
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Post by brobear on Aug 31, 2021 1:45:42 GMT -5
Tyrannosauridae famliy Comparing the massive skeleton of the front limb of a giant tyrannosaurid and a grown man. Arm bones of a giant tyrannosaurid (Zhuchengtyrannus magnus) and an adult man. Well, your bicep was NOT larger than that of a theropod! From my new book ′′ Dinosaurs - Records and Curiosities ′′ (′′ Dinosaurs - Records and Curiosities ′′-https://www.knihykazda.cz/dinosauri-rekordy-a-zajimavosti/). Artwork by Vladimír Rimbala.
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Post by brobear on Sept 4, 2021 7:18:18 GMT -5
Tyrannosauroidea It's time for another Beasts of the Mesozoic: Tyrannosaur Series package art reveal. Here is the Teratophoneus curriei, by Raul Ramos!
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Post by OldGreenGrolar on Sept 4, 2021 11:30:23 GMT -5
What the tyranosaurus does with its tiny arms is still a mystery.
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Post by brobear on Sept 8, 2021 14:31:17 GMT -5
Smilodon Producciones SEPTEMBER 8, 2021 NEW GIANT CARNIVOR DINOSAUR was a terror for the smaller tyrannosaurids A fossil jaw reveals that the great predator lived 90 million years ago Despite their fearsome reputation, tyrannosaurs were not always the biggest or fierce carnivores in the Mesozoic world. For tens of millions of years, previous Tyrannosaurus relatives lived in the shadow of larger carnivores with knife-like teeth. These predators were carcharodontosaurs or ′′ shark tooth lizards ", and paleontologists just named a new species from a crucial point in dinosaur history. The new dinosaur, represented by a bone found in Uzbekistan's 90-million-year-old rock, is an estimated carcharodontosaur at about 30 feet long. But that's not all. This new species of dinosaur also lived alongside a much smaller tyrannosaur and helps to downsize when the fearsome carcharodontosaurs began to yield the role of apex predator to larger and meaner tyrannosaurs. Named Ulughbegsaurus uzbekistanensis, the new dinosaur is described today in the Royal Society Open Science by paleontologist Kohei Tanaka of University of Tsukba, paleontologist Darla Zelenitsky from University of Calgary and her colleagues. So far, the dinosaur is only known by a single bone: part of the upper jaw discovered in the sandy sections of the Kyzylkum Desert. However, anatomical details of the bone indicate that it belonged to the largest predator of its environment. Ulughbegsaurus is not the first dinosaur found in the area. The fossil was preserved in what paleontologists knew as the Bissekty Formation, a pile of rocks ages 90 to 92 million that conserves the remains of dinosaurs with horns, duck peak dinosaurs, long-necked sauropod dinosaurs and more. ′′ The Bissekty Formation represents one of Europe's best known ecosystems and Asia of its time ", says Zelenitsky. Among the most remarkable findings in the geological section are the bones of Timurlengia, a tyrannosaurus that grew to about ten feet long. That's about a third of Ulughbegsaurus's body length. ′′ This is a new bone, and it's actually just part of a bone, but its importance far overshadow its appearance ", says Stephen Brusatte, a paleontologist at the University of Edinburgh, who did not participate in the new research. Ulughbegsaurus is not only now the last known carcharodontosaurus, but the discovery also alters what paleontologists thought about life in the Bissekty Formation. ′′ There may have been a complex interaction between Ulughbegsaurus and other smaller predatory dinosaurs ", says Zelenitsky, with species of different body sizes that prefer different species of prey. And this could have prevented tyrannosaurs from living big. Small tyrannosaurs and large carcharodontosaurs have previously been found in other fossil sites. In the 96 million-year-old rock of southeast Utah, for example, paleontologists have found the bones of a large carcharodontosaurus called Siats and a small tyrannosaurus called Moros. But the new finding, Zelenitsky and his colleagues, is the youngest occurrence of this carnivorous relationship that comes from a little-known time, just before the rise of tyrannosaurs. Paleontologists don't even understand the era of dinosaurs. Where are the fossils, how accessible they are to researchers, what kind of questions paleontologists want to study and more, it all influences the periods of time experts have come to know better. In terms of dinosaurs history, experts are struggling to understand the Cretaceous part between 80 and 125 million years ago. That's because that time period seems to have been one of significant changes. At that window, the northern hemisphere carcharodontosaurs went from apex predators to non-existent and, in their absence, tyrannosaurs began to grow more and more. Zelenitsky and his colleagues followed this trend as they observed the body sizes of tyrannosaurs and allosauroids, the group of large carnivorous dinosaurs that includes carcharodontosaurs. Some 160 million years ago, for example, Ancient China's first tyrannosaurus Guanlong was overshadowed by the much larger Sinraptor. The same relationship is evident in the Early Cretaceous, 125 million years ago, when tyrannosaurus lived alongside the largest Neovenator in prehistoric England. The co-occurrence of Ulughbegsaurus and small tyrannosaurus Timurlengiaencaja in this same pattern. ′′ For many tens of millions of years, tyrannosaurs were substitutes for allosauroids ", says Brusatte. Only in environments where there were no carnivores large competitors, tyrannosaurs became large. About 125 million years ago, for example, China's Lower Cretaceous was home to a large 30-foot-long tyrannosaurus called Yutyrannus. Paleontologists have not discovered any large carnivore in competition on the same rocks, which is in line with the trend that tyrannosaurs only bloomed in the absence of competition. The trend is especially evident after the 80 million year mark. By then, carcharodontosaurs could no longer be found in northern hemisphere habitats that used to rule and enormous tyrannosaurs as Dynamotror and Gorgosaurus were evolving. ′′ I think any findings we can make in or around the 90 to 80 million window can help shed light on this little-known interval of dinosaur-dominated ecosystems ", says Zelenitsky. Although the relationship between tyrannosaurs, body size and carnivores competitors now seems clear, paleontologists still don't know why carcharodontosaurs left their role as the largest predators in the northern hemisphere. It's unlikely that tyrannosaurs just made their way to the top. ′′ Since allosauroids have held tyrannosaurs for so many tens of millions of years ", Brusatte says, ′′ I can't imagine tyrannosaurians have suddenly figured out how to overcome allosauroides " Something else must have happened, with changes in old settings, including a change in the availability of prey species, as favored hypothesis. ′′ We don't know why these dinosaurs lost their place as top predators, but perhaps it was related to environmental changes that would have disrupted herbivorous dinosaur communities in this window of time or around ", Zelenitsky says. It will take more fossils to investigate further, to track how a group of stunning carnivores yielded the evolutionary stage to their crushing successors. SOURCE: Smithsonian Magazine Quote: Named Ulughbegsaurus uzbekistanensis
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Post by OldGreenGrolar on Sept 9, 2021 8:22:00 GMT -5
Brobear. You really know a lot about dinosaurs.
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Post by brobear on Sept 9, 2021 9:56:05 GMT -5
Brobear. You really know a lot about dinosaurs. I discover a lot from other people's hard work, and learn as I go.
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Post by brobear on Sept 10, 2021 3:32:32 GMT -5
It is highly unlikely that T-rex ever hunted the biggest dinosaur living in his kingdom. Alamosaurus! Largest specimens of Tyrannosaurus and Alamosaurus (FMNH PR 2081 and SMP-VP 1850). Tyrannosaurus is 12.3 meters TL and is 8.4 tonnes, while Alamosaurus is 34 meters TL and is 90 tonnes. Both skeletals by Scott Hartman.
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Post by OldGreenGrolar on Sept 10, 2021 9:00:12 GMT -5
I doubt any theropod count hunt a huge sauropod.
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Post by brobear on Sept 12, 2021 2:39:38 GMT -5
TYRANNOSAURUS REX - ( Facebook Group ) Possible Theropod/Tyrannosaurid Embryo Found on private land near Morrison Formation in New Mexico...This specimen was likely formed by way of calcification and (much later) mineralization of the contents within the egg environment and was most likely spared from decomposition and predation by scavengers due to rapid burial, possibly from a sudden flash flood, or muddy embankment collapse..This would have created the best conditions for this type of fossilization process to occur..although more common in marine fossils, any dead organic matter can become mineralized in its own likeness, as is seen with this specimen..Even as the original organic matter within the egg decomposes, it is replaced by fine silicates, and eventually, the entire form of what was once there is completely replaced by these fine particles..Not unlike the way the pixels on a flat-screen TV come together to form the whole picture, that is generally how the mineralization process occurs, and the smaller the silicates are that make up the form of the fossil, the greater the clarity and detail of the fossil itself..Although some small eggshell fragments remain, much of it is gone, having done its job of protecting the embryo inside..even in death.
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Post by brobear on Sept 13, 2021 1:21:22 GMT -5
Dinosaur that gave a tough competition to T rex, New dino discovered- Ulughbegsaurus This title is misleading, as headlines often are.
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Post by brobear on Sept 15, 2021 7:12:18 GMT -5
*T.rex - ‘Scotty’ from Saskatchewan for Canadian Coin Paleoart by Julius Csotonyi (Royal Tyrrell Museum of Palaeontology) *This is how I view T-rex; not the fast-running, quick 'duck-and-dodge' predator but rather the massive brute who can bulldoze over an adversary and kill with brute force and super-powerful jaws.
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Post by brobear on Sept 23, 2021 8:49:26 GMT -5
www.sciencedaily.com/releases/2021/08/210825143032.htm Tyrannosaurus rex, the fearsome predator that once roamed what is now western North America, appears to have had an East Coast cousin. A new study describes two dinosaurs that inhabited Appalachia -- a once isolated land mass that today composes much of the eastern United States -- about 85 million years ago: an herbivorous duck-billed hadrosaur and a carnivorous tyrannosaur. Brownstein examined a partial skeleton of a large predatory therapod, concluding that it is probably a tyrannosaur. He noted that the fossil shares several features in its hind limbs with Dryptosaurus, a tyrannosaur that lived about 67 million years ago in what is now New Jersey. The dinosaur has different hands and feet than T. rex, including massive claws on its forelimbs, suggesting that it represents a distinct family of the predators that evolved solely in Appalachia. "Many people believe that all tyrannosaurs must have evolved a specific set of features to become apex predators," Brownstein said. "Our fossil suggests they evolved into giant predators in a variety of ways as it lacks key foot or hand features that one would associate with western North American or Asian tyrannosaurs."
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Post by OldGreenGrolar on Sept 23, 2021 9:53:17 GMT -5
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Post by OldGreenGrolar on Sept 23, 2021 9:53:59 GMT -5
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Post by OldGreenGrolar on Sept 23, 2021 10:00:04 GMT -5
Not a t rex but his close relative.
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Post by brobear on Sept 25, 2021 6:24:26 GMT -5
A juvenile Tyrannosaurus rex is excited about something! Artwork by RJ Palmer. If we could take a time-trip back beyond 65 million years ago, the big full-grown T-rex would not likely pose a huge threat to human-sized prey. But the juveniles... RUN!!!
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Post by OldGreenGrolar on Oct 1, 2021 7:49:48 GMT -5
Yeah the juveniles would be more likely to hunt us.
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