Dinosaurs: New Findings & Theories

ramonmercado

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Fossil hunters in Chile have unearthed the remains of a bizarre Jurassic dinosaur that combined a curious mixture of features from different prehistoric animals.

The evolutionary muddle of a beast grew to the size of a small horse and was the most abundant animal to be found 145 million years ago, in what is now the Aysén region of Patagonia.

The discovery ranks as one of the most remarkable dinosaur finds of the past 20 years, and promises to cause plenty of headaches for paleontologists hoping to place the animal in the dinosaur family tree.

“I don’t know how the evolution of dinosaurs produced this kind of animal, what kind of ecological pressures must have been at work,” said Fernando Novas at the Bernardino Rivadavia Natural Sciences Museum in Buenos Aires. ...

http://www.theguardian.com/science/...iegosuarezi-discovered-in-remarkable-new-find
 

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A British graduate student says he’s found a way to tell the difference between male and female stegosaurs, and perhaps dinosaurs in general. But critics are already attacking the study’s methodology and ethics. “I would have rejected this paper on a number of grounds,” says Kevin Padian, a paleontologist at the University of California, Berkeley.

The study began in 2009 when Evan Saitta, then a high school student, volunteered to help dig up dinosaur bones at a Montana quarry. Over the next several years, Saitta—now in graduate school at the University of Bristol in the United Kingdom—scraped five stegosaurs’ skeletons out of the rock and noticed something odd about their broad, jutting back plates. Most specimens of this particular species,Stegosaurus mjosi, have wide, oval plates, Saitta says. “We had plates like that, but we also had the exact opposite: tall, narrow plates. Something you don’t expect.”

When Saitta studied stegosaur fossils around the world as an undergraduate at Princeton University, he saw the same pattern: Some skeletons had the wide plates; others had the narrow ones. Noticing that his fossil plates from Montana had been evenly divided between the two types, he began to wonder if the plates marked a telltale difference between male and female stegosaurs, perhaps akin to moose antlers. ...

http://news.sciencemag.org/paleontology/2015/04/dino-sexing-study-slammed-critics
 

Monstrosa

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You've posted the steg story before.
 

Analis

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Giant sea lizards in the age of dinosaurs: A new beginning for baby mosasaurs

Date:

April 10, 2015

Source:

Yale University

Summary:

They weren't in the delivery room, but researchers have discovered a new birth story for a gigantic marine lizard that once roamed the oceans. Thanks to recently identified specimens, paleontologists now believe that mighty mosasaurs -- which could grow to 50 feet long -- gave birth to their young in the open ocean, not on or near shore.


http://www.sciencedaily.com/releases/2015/04/150410165316.htm

This theory has nothing new, viviparity in mosasaurids had already been widely accepted for years. This kind of dishonnest 'scientific' announcement, to catch attention or take undue credit for a discovery, is not unusual. A few years ago, a theory that elephants had aquatic ancestors had similarly been falsely presented as being new (it was in fact more than one century old !).
 

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It's the "where" they birthed, not the fact they were viviparous that is the news here.
 

Analis

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Well, I don't see which sense it would make for a viviparous animal to give birth on or close to shore. And they explicitely state that "contrary to classic theories, these findings suggest that mosasaurs did not lay eggs on beaches" – so that (the novelty of viviparity) is indeed what they had in mind (or so they say).
 

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A bizarre new flying dinosaur, with bat-like wings and feathers

When it comes to big fossil finds, China is full of surprises. The latest dinosaur discovery, announced today in Nature, is a bizarre chicken-sized animal with a delightfully short scientific name, Yi qi, Mandarin for “strange wing” (pronounced “yee chee”).

Yi is a new type of scansoriopterygid, a family of small feathered dinosaurs with unusually long fingers, including forms like Epidexipteryx.


The extensively feathered fossil of Yi hails from the Middle-Late Jurassic (160-165 million years old) of Hebei Province, in northern China. It preserves a rod-like prop extending from the wrist along with patches of bare, featherless tissue around the hands.

The most likely explanation is that the digits and bony rod supported membranous wing like in modern bats or mythical dragons. It is unclear if Yi was capable of powered flight or simply glided. ...


Read more at http://www.deepstuff.org/a-bizarre-...-like-wings-and-feathers/#LcliLdITUzAQ0u7u.99
 

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When the truth mixes with fiction : Yi is remarkably similar to the Flurrit (Labisaurus alatus) imagined by Dougal Dixon in his book The new dinosaurs : an alternative evolution, a gliding coelurosaur with a patagium, except that it was supported by only one finger.


http://www.sivatherium.narod.ru/library/Dixon_2/07_en.htm
 

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Thinking of it, an even more striking lookalike from the field of speculative/alternative zoology is the vultursaur from The world of Kong : a natural history of Skull Island. It was imagined as a flying coelurosaur with bat-like wings, and looks almost exactly like Yi. The only difference was that it had a bare smooth skin. While Yi, like the Flurrit, had the kind of downy skin that seems usual for coelurosaurs.
 

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Using the fossil record as a guide, a research team led by Yale paleontologist and developmental biologist Bhart-Anjan S. Bhullar and Harvard developmental biologist Arhat Abzhanov conducted the first successful reversion of a bird's skull features. The scientists replicated ancestral molecular development to transform chicken embryos in a laboratory into specimens with a snout and palate configuration similar to that of small dinosaurs such as Velociraptor and Archaeopteryx.

Just don't call them dino-chickens.

"Our goal here was to understand the molecular underpinnings of an important evolutionary transition, not to create a 'dino-chicken' simply for the sake of it," said Bhullar, lead author of the study, published online May 12 in the journal Evolution. ...

http://www.sciencedaily.com/releases/2015/05/150512075417.htm
 

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A new study shows that dinosaur eggs might actually have been blue-green instead of the dull brown or gray we usually imagine and see depicted in movies.

The study, which has yet to be published in a peer-reviewed journal, is available online at PeerJ Preprints. In it, a team of scientists from the University of Bonn in Germany, found that two pigments that provide color for modern-day bird eggshells also existed in the eggshells of the dinosaur Heyuannia huangi.

According to the researchers, protoporphyrin (PP) and biliverdin (BV) are the pigments that color chicken eggs reddish brown and the eggs of robins and emus blue. They also noted that the color of the eggshell also depends on the type of nest that birds usually have—birds with open nests use specific colors to camouflage their eggs.


More from: http://www.gmanetwork.com/news/stor...gs-were-vibrantly-colorful-new-research-shows
 

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About 10 years ago, Peter Hews stumbled across some bones sticking out of a cliff along the Oldman River in southeastern Alberta, Canada. Now, scientists describe in the Cell Press journal Current Biology on June 4 that those bones belonged to a nearly intact skull of a very unusual horned dinosaur—a close relative of the familiar Triceratops that had been unknown to science until now.


"The specimen comes from a geographic region of Alberta where we have not found horned dinosaurs before, so from the onset we knew it was important," says Dr. Caleb Brown of the Royal Tyrrell Museum of Palaeontology in Alberta, Canada. "However, it was not until the specimen was being slowly prepared from the rocks in the laboratory that the full anatomy was uncovered, and the bizarre suite of characters revealed. Once it was prepared it was obviously a new species, and an unexpected one at that. Many horned-dinosaur researchers who visited the museum did a double take when they first saw it in the laboratory."

Brown likes to say, only partly in jest, that the uniqueness of this specimen was so obvious that you could tell it was a new species from 100 meters away. ...

http://phys.org/news/2015-06-species-horned-dinosaur-bizarre-features.html
 

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Dinosaurs once dominated the world — but they spent their first 30 million years stranded on its geographic fringes. Large dinosaurs flourished near the poles, but only a few small ones, no larger than ostriches, managed to gain a foothold in the hotter low latitudes1.

The latest research2 suggests that an unstable climate in these regions kept big dinosaurs at bay for millions of years, as conditions at lower latitudes swung violently between wet and dry periods.

The finding is based on a detailed climate history reconstructed from sedimentary rock in New Mexico that dates from about 215–205 million years ago, during the late Triassic period. Back then, the area sat just north of the equator, roughly where Costa Rica is today. The region was dominated by archaic reptiles (some related to crocodiles), with only a few small dinosaur species present3.

Jessica Whiteside, an organic geochemist at the University of Southampton, UK, who led the study, tracked ancient plant growth by analysing carbon isotopes in nodules of petrified soil in the rock layers. She found repeated spikes and dips in the amount of ‘heavy’ carbon-13, a sign of major ecological disruption. These spikes lined up with sudden changes in fossil pollen trapped in the rocks, indicating periodic shifts between plant species adapted to wet conditions and those that preferred an arid environment. ...

http://www.nature.com/news/extreme-climate-change-slowed-dinosaurs-rise-1.17728
 

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Raptor tracker
Researchers hot on the trail of Velociraptor relative
Date:
June 11, 2015
Source:
University of Alberta
Summary:
In a discovery seemingly straight from the movie 'Jurassic World,' researchers have just documented a rich fossil footprint site in central China containing tracks by several kinds of dinosaurs, including raptors. From these tracks, the team has gained new insights into how raptors moved. ...

http://www.sciencedaily.com/releases/2015/06/150611161259.htm
 

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The fossilised snout of a giant flying reptile unearthed on the Isle of Wight is the first of its kind to be discovered on the island. The Coloborhynchus remains were found by Will Thurbin, from Niton.

Experts at Dinosaur Isle Museum and the University of Portsmouth confirmed it was the pterosaur's first definite appearance on the Isle of Wight. Scientists believe it to be about 125 million years old, which could make it the oldest example ever found.

A previous discovery, uncovered during the 19th Century near Cambridge, dates back 100 million years.

http://www.bbc.com/news/uk-england-hampshire-33445395
 

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Scientists have discovered a winged dinosaur - an ancestor of the velociraptor - that they say was on the cusp of becoming a bird.

The 6ft 6in (2m) creature was almost perfectly preserved in limestone, thanks to a volcanic eruption that had buried it in north-east China.

And the 125-million year-old fossil suggests many other dinosaurs, including velociraptors, would have looked like "big, fluffy killer birds".

But it is unlikely that it could fly. :(

http://www.bbc.com/news/science-environment-33510288
 

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Scientists have discovered a winged dinosaur - an ancestor of the velociraptor - that they say was on the cusp of becoming a bird.

The 6ft 6in (2m) creature was almost perfectly preserved in limestone, thanks to a volcanic eruption that had buried it in north-east China.

And the 125-million year-old fossil suggests many other dinosaurs, including velociraptors, would have looked like "big, fluffy killer birds".

But it is unlikely that it could fly. :(

http://www.bbc.com/news/science-environment-33510288
Am I the only person who is increasing uncomfortable with all these creatures being found with more and more adaptations for flight before they seemed to be able to fly. For some time, I've felt we're missing an evolutionary link in this story. I think it may yet turn out some early dinosaurs developed flight with the accompanying characteristics, and some of them then returned to the ground, evolving into the many bird like but flightless theropods we keep finding. As it is, to hold a dinosaur up to us with so many adaptations for flight, and say it was well on its way to becoming a bird but couldn't fly, seems to be turning evolution on its head.
 

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Researchers have examined one of the smallest parts of the fossil record–theropod teeth–to shed light on the evolution of dinosaurs at the end of the Cretaceous. Findings published in the prestigious journalActa Palaeontologica Polonica have effectively quadrupled the dinosaur diversity in the area of study, eight localities from Treviño County, Huesca and Lerida–including the exceptional site of Laño. There were previously only two known species in the area.

The study of 142 isolated teeth from the Campanian-Maastrichtian of the South Pyrenean Basin suggests six additional species of toothed theropods (five small, one large) were present in the region. “Studying these small parts helps us reconstruct the ancient world where dinosaurs lived and to understand how their extinction happened,” says lead author Angelica Torices, post-doctoral fellow in biological sciences at the University of Alberta. “Teeth are especially important in the study of Upper Cretaceous creatures in Spain and the rest of Europe because we don’t have complete skeletons of theropods from that time in those locations. We have to rely on these small elements to reconstruct the evolution of these dinosaurs, particularly the theropods.”


Read more at http://www.deepstuff.org/big-dinosaur-discoveries-in-tiny-toothy-packages/#wb4lB6jWmzyPtVsE.99
 

Analis

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Am I the only person who is increasing uncomfortable with all these creatures being found with more and more adaptations for flight before they seemed to be able to fly. For some time, I've felt we're missing an evolutionary link in this story. I think it may yet turn out some early dinosaurs developed flight with the accompanying characteristics, and some of them then returned to the ground, evolving into the many bird like but flightless theropods we keep finding. As it is, to hold a dinosaur up to us with so many adaptations for flight, and say it was well on its way to becoming a bird but couldn't fly, seems to be turning evolution on its head.
In my opinion, the newfound Zhenoulanglong could probably perform some very limited flight, although that's not really the point, as it doesn't say if it evolved from an ancestor who was a better flyer, or even an accomplished flyer (incidently, when Dr Bill Sellers says that there was "a huge range of these early bird-like dinosaurs, some [...] running around on the ground and some [] experimenting with early flight", he seems to make the common mistake to believe that flight couldn't evolve from the ground). Probably, some early maniraptoran coelurosaur had developped an ability to fly,more or less advanced, and some of its descendants lost it, as has happened on multiple occasions in the history of birds.

But here, we have shades of the old Olshovski's theory that dinosaurs were in fact all birds having lost the flight ability, and it certainly has its merits. Although that taken to its extremities, it's not very likely, as ornitischians do not exhibit putative adaptations to flight ; nonetheless recent discoveries suggest they were endotherms and covered with downy hair from the start. But when applied to theropods, and not only to maniraptorans, it's plausible. It's also true with the common ancestor of saurischians, as sauropods had airsacks, like theropods. So that a brachiosaur or a diplodocus would in fact truly be gigantic primitive birds that had re-learned to walk on their four feet.

This would also mean that ironically, birds would be the most typical theropods. In any case, as early dinosaurs like Eoraptor were basically theropod-like, they remained the most typical dinosaurs.
 
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Decades of research on Montana's state fossil—the "good mother lizard" Maiasaura peeblesorum - has resulted in the most detailed life history of any dinosaur known and created a model to which all other dinosaurs can be compared, according to new research published recently in the journal Paleobiology.

Researchers from Oklahoma State University, Montana State University and Indiana Purdue University used fossils collected from a huge bonebed in western Montana for their study.

"This is one of the most important pieces of paleontology involving MSU in the past 20 years," said Jack Horner, curator of the Museum of the Rockies at MSU. "This is a dramatic step forward from studying fossilized creatures as single individuals to understanding their life cycle. We are moving away from the novelty of a single instance to looking at a population of dinosaurs in the same way we look at populations of animals today."

The study was led by Holly Woodward, who did the research as her doctoral thesis in paleontology at MSU. Woodward is now professor of anatomy at Oklahoma State University Center for Health Sciences.

The Paleobiology study examined the fossil bone microstructure, or histology, of 50 Maiasaura tibiae (shin bones). Bone histology reveals aspects of growth that cannot be obtained by simply looking at the shape of the bone, including information about growth rate, metabolism, age at death, sexual maturity, skeletal maturity and how long a species took to reach adult size.

http://phys.org/print363020264.html
 

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Newly Described Dakotaraptor: A Giant Raptor From The Hell Creek Formation

Most Dromaeosaurs (raptors) were small dinosaurs about the size of the turkey or dog. For decades fossil teeth have been found hinting at the presence of a gigantic type of Dromaeosaur in the Hell Creek Formation of South Dakota. Based on the remains of an adult individual discovered in South Dakota in 2005 a new genus of gigantic, feathered raptor has just been described in a paper published by the University of Kansas Paleontological Institute. Dakotaraptor steini, represents the first giant Dromaeosaur from the Hell Creek Formation, and the most recent in the fossil record worldwide.

At an estimated 16 1/2 feet long and sporting a 7.5 inch killing clawDakotaraptor would have been a terror to any herbivores in its territory. The discovery from the quarry in South Dakota contained the bones of both arms, some leg bones, 10 caudal vertebrae, a few other associated bones, and the infamous sickle-like foot claw.



3D rendering of Dakotaraptor by RJ Palmer, produced for Urvogel Games LLC's in-development game Saurian

The most startling item revealed from the analysis of the bones were the presence of “Quill Knobs” located on the ulna. The robustness of these attachment points for feathers would have given Dakotaraptor very long wings when outstretched. While Dakotaraptorwas far too large of a creature for flight it is suggested that it could have used its large wings to stabilize itself when pinning down prey.

Etc...

https://www.fossilera.com/blog/first-giant-raptor-dromaeosaur-described-from-hell-creek-formation

As I've said elsewhere, these raptors seem too avian to me. I struggle to believe they were not descended from a flying ancestor.
 

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Birds are descended from them. Birds are the surviving dinosaurs.
 

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A rare fossil from eastern North America of a dog-sized horned dinosaur has been identified by Dr Nick Longrich. The fossil provides evidence of an east-west divide in North American dinosaur evolution.

During the Late Cretaceous period, 66-100 million years ago, the land mass that is now North America was split in two continents by a shallow sea, the Western Interior Seaway, which ran from the Gulf of Mexico to the Arctic Ocean. Dinosaurs living in the western continent, called Laramidia, were similar to those found in Asia.

However, few fossils of animals from the eastern 'lost continent' of Appalachia have been found because these areas being densely vegetated, making it difficult to discover and excavate fossils.

Dr Longrich, from the Milner Centre for Evolution based in our Department of Biology & Biochemistry, studied one of these rare fossils, a fragment of a jaw bone kept in the Peabody Museum at Yale University. It turned out to be a member of the horned dinosaurs - the Ceratopsia.

His study, published in the journal Cretaceous Research, highlights it as the first fossil from a ceratopsian dinosaur identified from this period of eastern North America.

http://phys.org/news/2015-11-rare-fossil-horned-dinosaur-lost.html
 

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A rare fossil from eastern North America of a dog-sized horned dinosaur has been identified by Dr Nick Longrich. The fossil provides evidence of an east-west divide in North American dinosaur evolution.

During the Late Cretaceous period, 66-100 million years ago, the land mass that is now North America was split in two continents by a shallow sea, the Western Interior Seaway, which ran from the Gulf of Mexico to the Arctic Ocean. Dinosaurs living in the western continent, called Laramidia, were similar to those found in Asia.

However, few fossils of animals from the eastern 'lost continent' of Appalachia have been found because these areas being densely vegetated, making it difficult to discover and excavate fossils.

Dr Longrich, from the Milner Centre for Evolution based in our Department of Biology & Biochemistry, studied one of these rare fossils, a fragment of a jaw bone kept in the Peabody Museum at Yale University. It turned out to be a member of the horned dinosaurs - the Ceratopsia.

His study, published in the journal Cretaceous Research, highlights it as the first fossil from a ceratopsian dinosaur identified from this period of eastern North America.

http://phys.org/news/2015-11-rare-fossil-horned-dinosaur-lost.html
Looks cute in the picture. I'd have one of those as a pet.
 

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