Dinosaurs: New Findings & Theories

Sharon Hill

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Any truth to the idea I heard in passing that Tyrannosaurus Rex wasn't a fearsome hunter, but a carrion dinosaur, like a hyena or a vulture in these times?
That was Jack Horner's idea 20 years ago and it just doesn't stand up. It probably ate carrion if it came across it as it could intimidate anything else but plenty of evidence shows that it evolved for hunting and that it took down live animals. As this commentary shows, it was a false debate. No one really took it very seriously. https://www.nationalgeographic.com/...7/16/time-to-slay-the-t-rex-scavenger-debate/
 

GNC

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That was Jack Horner's idea 20 years ago and it just doesn't stand up. It probably ate carrion if it came across it as it could intimidate anything else but plenty of evidence shows that it evolved for hunting and that it took down live animals. As this commentary shows, it was a false debate. No one really took it very seriously. https://www.nationalgeographic.com/...7/16/time-to-slay-the-t-rex-scavenger-debate/
Thanks for the info! I suppose there must have been carrion dinos, but the T-Rex definitely wasn't one of them.
 

lordmongrove

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T.rex had an estimated top speed of 25 mph, good binocular vision and the most powerful bite force of any dinosaur. These are traits of a hunter.We know it left bite marks and tooth fragments in prey species that managed to escape and survive.
 

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Determining the body temperature of dinosaurs via the chemical composition of dino eggs.

https://phys.org/news/2020-02-dinosaur-parents-kids-fever.html

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To verify their hypothesis, Affek and her team needed to determine the environmental temperature in Alberta back when dinosaurs lived. They accomplished this by applying their isotope method to mollusk shells that lived in Alberta alongside the dinosaurs. Since mollusks are cold-blooded creatures, they reflect the ambient climate of the time. The mollusks' body temperature measured 26°C and showed that the dinosaurs living in Alberta were endothermic; otherwise, they could not have maintained a body temperature of 35-40°C.
 
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Determining the body temperature of dinosaurs via the chemical composition of dino eggs.

https://phys.org/news/2020-02-dinosaur-parents-kids-fever.html

-------------------------------------------
To verify their hypothesis, Affek and her team needed to determine the environmental temperature in Alberta back when dinosaurs lived. They accomplished this by applying their isotope method to mollusk shells that lived in Alberta alongside the dinosaurs. Since mollusks are cold-blooded creatures, they reflect the ambient climate of the time. The mollusks' body temperature measured 26°C and showed that the dinosaurs living in Alberta were endothermic; otherwise, they could not have maintained a body temperature of 35-40°C.

More on this hot stuff.

An analysis of fossil eggshells may have settled a long-running debate about dinosaurs, suggesting that all species were warm-blooded.

This also means the ancestors of dinosaurs must have been warm-blooded too, says Robin Dawson at Yale University, who led the research.

It is now mostly agreed that the feathered dinosaurs called theropods that gave rise to birds were warm-blooded, but there is still a debate about whether other groups of dinosaurs were too. Until recently, we had only indirect methods of working out the body temperature of ancient animals, so there was no way to be sure.

There is a way to work out the temperature at which organic matter forms inside bodies based on carbon and oxygen isotopes. This technique can be applied to eggshells to reveal the body temperature of the mother when the shells formed.

In 2015, researchers applied this method to the eggshell of a theropod and a sauropod – a long-necked dinosaur – and found both were warm-blooded. Now Dawson’s team has applied this method to three more fossil eggshells.

Read more: https://www.newscientist.com/articl...st-dinosaurs-were-warm-blooded/#ixzz6EDe1l2UK
 
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So it wasn't just dinos playing pranks.

The mystery surrounding dinosaur footprints on a cave ceiling in Central Queensland has been solved after more than a half a century.

University of Queensland paleontologist Dr. Anthony Romilio discovered pieces to a decades-old puzzle in an unusual place—a cupboard under the stairs of a suburban Sydney home.

"The town of Mount Morgan near Rockhampton has hundreds of fossil footprints and has the highest dinosaur track diversity for the entire eastern half of Australia," Dr. Romilio said.

"Earlier examinations of the ceiling footprints suggested some very curious dinosaur behavior; that a carnivorous theropod walked on all four legs. You don't assume T. rex used its arms to walk, and we didn't expect one of its earlier predatory relatives of 200 million years ago did either."

https://phys.org/news/2020-02-mystery-dinosaur-footprints-cave-ceiling.html
 
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Germany: Mini-dinosaur fossil discovery hailed as 'sensation'

Source: dw.com
Date: 21 February, 2020

The tiny skull of a miniature dinosaur has been discovered in Germany, scientists from the Stuttgart Natural History Museum announced on Thursday.

The fossil was found in a quarry in the town of Vellberg in the state of Baden-Wurttemberg, and belongs to a new type of dinosaur of around 10 centimeters (3.9 inches) in length. The creature is believed to have lived around 240 million years ago.

"It is a scientific sensation," said paleontologist Rainer Schoch. The miniature skull shows a great deal of similarities to modern-day lizards and snakes.

"The little animal is exciting, because we know so little about the ancestors of lizards and snakes," Schoch explained. "We have discovered a new species."

The "mini-dinosaur" has been given the scientific name Vellbergia bartholomaei, after the name of the town where it was discovered and the fossil collector Alfred Bartholomä.

The creature existed on earth around 20 million years before large dinosaurs evolved. The 12-millimeter long skull was examined under a tomograph to determine how the dinosaur ate and the size of its brain.

https://amp-dw-com.cdn.ampproject.o...ssil-discovery-hailed-as-sensation/a-52458554
 

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Cartilage cells, chromosomes and DNA preserved in 75 million-year-old baby duck-billed dinosaur

Source: phys.org
Date: 29 February, 2020

This study is lead by Dr. Alida Bailleul (Institute of Vertebrate Paleontology and Paleoanthropology, the Chinese Academy of Sciences) and Dr. Mary Schweitzer (North Carolina State University, NC Museum of Natural Sciences, Lund University and Museum of the Rockies). Microscopic analyses of skull fragments from these nestling dinosaurs were conducted by Alida Bailleul at the Museum of the Rockies.

In one fragment she noticed some exquisitely preserved cells within preserved calcified cartilage tissues on the edges of a bone. Two cartilage cells were still linked together by an intercellular bridge, morphologically consistent with the end of cell division (see left image below). Internally, dark material resembling a cell nucleus was also visible. One cartilage cell preserved dark elongated structures morphologically consistent with chromosomes. "I couldn't believe it, my heart almost stopped beating," Bailleul says.

https://phys.org/news/2020-02-cartilage-cells-chromosomes-dna-million-year-old.html
 

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Tiny 44 million year old bird fossil links Africa and Asia to Utah

Source: heritagedaily.com
Date: 3 March, 2020

A new species of quail-sized fossil bird from 44 million year old sediments in Utah fills in a gap in the fossil record of the early extinct relatives of chickens and turkeys, and it shows strong links with other extinct species from Namibia in Southern Africa and Uzbekistan in Central Asia.

In their paper in the online scientific journal Diversity, the authors Dr. Thomas Stidham (Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences), Dr. Beth Townsend (Midwestern University, Arizona), and Dr. Patricia Holroyd (University of California Museum of Paleontology, Berkeley) describe the fossil of a distinct tiny bone from the shoulder girdle of an extinct quail-like bird from 44 million year old rocks in eastern Utah.

While it is a unique fossil, the authors have not given it a formal scientific name, waiting until they find more bones of the skeleton. This new Utah bird appears to be the oldest fossil of the extinct group called Paraortygidae, a relative of the living Galliformes (the group that includes the living chicken, turkey, guineafowl, and quail). This fossil fits in a nearly 15 million-year gap in the fossil record of the galliform lineage in North America.

https://www.heritagedaily.com/2020/...d-fossil-links-africa-and-asia-to-utah/126075
 
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A feathered, scaly wolf.

A wolf-sized warrior, kin to the fierce, feathered Velociraptor, prowled what is now New Mexico about 68 million years ago.

Dineobellator notohesperus was a dromaeosaur, a group of swift, agile predators that is distantly related to the much larger Tyrannosaurus rex. The discovery of this new species suggests that dromaeosaurs were still diversifying, and even becoming better at pursuing prey, right up to the end of the Age of Dinosaurs, researchers say March 26 in Scientific Reports.

That age came to an abrupt close at the end of the Cretaceous Period about 66 million years ago, when a mass extinction event wiped out all nonbird dinosaurs. A gap in the global fossil record for dromaeosaurs near the end of the Cretaceous had led some scientists to wonder whether the group was already in decline before the extinction, says Steven Jasinski, a paleontologist at the State Museum of Pennsylvania in Harrisburg (SN: 4/21/16). The new find suggests otherwise.

https://www.sciencenews.org/article/fossils-new-dromaeosaur-date-end-age-dinosaurs
 
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