Causes for the Extinction of Dinosaurs

More than 90 percent of all organisms that have ever lived on Earth are extinct. As new species evolve to fit ever changing ecological niches, older species fade away. But the rate of extinction is far from constant. At least a handful of times in the last 500 million years, 50 to more than 90 percent of all species on Earth have disappeared in a geological blink of the eye..

The causes of these mass extinction events are unsolved mysteries, though volcanic eruptions and the impacts of large asteroids or comets are prime suspects in many of the cases. Both would eject tons of debris into the atmosphere, darkening the skies for at least months on end. Starved of sunlight, plants and plant-eating creatures would quickly die. Space rocks and volcanoes could also unleash toxic and heat-trapping gases that—once the dust settled—enable runaway global warming.

Massive floods of lava erupting from the central Atlantic magmatic province about 200 million years ago may explain the Triassic-Jurassic extinction. About 20 percent of all marine families went extinct, as well as most mammal-like creatures, many large amphibians, and all non-dinosaur archosaurs. An asteroid impact is another possible cause of the extinction, though a telltale crater has yet to be found. 

Curly Horned Wendiceratops

A newly-named dinosaur whose head frill was adorned with curly horns has joined the ranks of the legendary family that includes the Triceratops, paleontologists said on Wednesday. The lumbering creature is named Wendiceratops pinhornensis, after the fossil hunter Wendy Sloboda, who first discovered the trove of some 200 bones in southern Alberta, Canada, said the study in the journal PLOS ONE.

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The plant-eating dinosaur lived about 79 million years ago, weighing more than a ton and measuring about 20 feet long. In all, more than 200 bones were collected from the Oldman Formation of southern Alberta, near the border with the US state of Montana, in 2011.

Paleontologists said the bones belonged to three adults and one juvenile. 

Modern Birds Descended From Dinosaurus

Modern birds descended from a group of two-legged dinosaurs known as theropods, whose members include the towering Tyrannosaurus rex and the smaller velociraptors. The theropods most closely related to avians generally weighed between 100 and 500 pounds — giants compared to most modern birds — and they had large snouts, big teeth, and not much between the ears. A velociraptor, for example, had a skull like a coyote's and a brain roughly the size of a pigeon's.

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In the 1990s, an influx of new dinosaur fossils from China revealed a feathery surprise. Though many of these fossils lacked wings, they had a panoply of plumage, from fuzzy bristles to fully articulated quills. The discovery of these new intermediary species, which filled in the spotty fossil record, triggered a change in how paleontologists conceived of the dinosaur-to-bird transition. Feathers, once thought unique to birds, must have evolved in dinosaurs long before birds developed.

In modern birds, two bones known as the premaxillary bones fuse to become the beak. That structure is quite distinct from that of dinosaurs, alligators, ancient birds and most other vertebrates, in which these two bones remain separate, shaping the snout. To figure out how that change might have arisen, the researchers mapped out the activity of two genes that are expressed in these bones in a spectrum of animals: alligators, chickens, mice, lizards, turtles and emus, a living species reminiscent of ancient birds.. 

Scientific Research on Dinosaurs History

The work of UMD Professor Arthur Aufderheide and a group of research scientists...on what are billed as "the nearly all amazing dinosaur fossil finding of the century"... will be featured in a forthcoming primetime Discovery Channel documentary by title "Secrets of the Dinosaur Mummy".

Dr. Aufderheide is a UMD professor in the Department of Pathology & Laboratory Medicine. The documentary chronicles the hard work of Dr. Aufderheide and the research group on the dinosaur nicknamed "Leonardo" - the world's most complete dinosaur fossil yet found.

"Leonardo" is the only dinosaur ever discovered since 1908. "Leonardo" was discovered by a field research team in 2001 in Malta, Montana. It has its entire skin layer its body. September 14 at 8 P.M, the one-hour program airs on Sunday.

Source: northlandsnewscenter.com

Oviraptor dinosaurs might contain waved their flexible tail feathers, in an approach that resembles the behavior of a modern-day peacock, to magnetize potential mates, an innovative learn has recommended. The dinosaur lived in the late Cretaceous era, concerning 75 million years ago and got its name, Latin for "egg thief", since the first specimen was establish near a clutch of eggs as if the creature were stealing them, but it was afterward exposed that the eggs be probable its own.

Oviraptor dinosaurs might contain waved their flexible tail feathers, in an approach that resembles the behavior of a modern-day peacock, to magnetize potential mates, an innovative learn has recommended. The dinosaur lived in the late Cretaceous era, concerning 75 million years ago and got its name, Latin for "egg thief", since the first specimen was establish near a clutch of eggs as if the creature were stealing them, but it was afterward exposed that the eggs be probable its own.