Thursday, September 4, 2014

[Geology2] Giant dinosaur discovered! Dreadnoughtus weighed as much as 7 T-Rexes



Giant dinosaur discovered! Dreadnoughtus weighed as much as 7 T-Rexes

Dreadnoughtus schrani
Caption Dreadnoughtus schrani
Mark A. Klingler / Carnegie Museum of Natural History
An artist's depiction of two Dreadnoughtus schrani menacing a much smaller meat-eating dinosaur.
Dreadnoughtus schrani
Caption Dreadnoughtus schrani
Mark A. Klingler / Carnegie Museum of Natural History
Dreadnoughtus had a 37-foot-long neck, 30-foot tail, and weighed an estimated 65 tons, making it the most massive land animal whose size can be confidently calculated.
Dreadnoughtus schrani
Caption Dreadnoughtus schrani
Kenneth Lacovara
Paleontologist Kenneth Lacovara with the right tibia of Dreadnoughtus.
Dreadnoughtus schrani
Caption Dreadnoughtus schrani
Kenneth Lacovara

A pair of bones called a "chevron." These bones are from the bottom of the tail. These have an unusually large surface for muscle attachment, indicating that this dinosaur's tail was extremely muscular and powerful.


Antarctica Museum of Natural History

Newly discovered Dreadnoughtus dinosaur weighed more than Boeing 737. Fossils from a massive dinosaur are found in southern Patagonia. Should we check Antarctica next?

Scientists have just announced the discovery of Dreadnoughtus schrani, a hulking dinosaur that stood two stories tall at its shoulder, and weighed as much seven Tyrannosaurus Rex. 

From head to tail, this guy was 85 feet long. Its neck alone was 37 feet long. Behind its massive house-sized body, a thick muscular tail stretched an additional 30 feet. 

Scientists cannot say for certain that it is the largest dinosaur ever found, but it is certainly right up there.

Even its name is a tribute to its gigantic size. Dreadnought means "fearing nothing" and is the name of tank-like battleships used in the early 20th century.

Nothing could have attacked Dreadnoughtus schrani and won, researchers say. It was too big. 

Dreadnoughtus is a titanosaurian sauropod, a diverse group of dinosaurs that lived in the Southern Hemisphere during the last 30 million years of the age of the dinosaurs. They were herbivores with long necks, relatively small heads, and long tails, and they are generally believed to be among the largest animals to walk Earth.

Based on the size of its femur bones (the thigh bone) and its humerus (the upper arm bone) scientists say Dreadnoughtus weighed 65-tons (130,000 pounds) when it died 66 million to 84 million years ago. (They are still working on getting a more precise age).

That's more than the weight of a Boeing 737. That's about the weight of 12 African elephants. 

And here's the kicker: Skeletal evidence suggests that at the time of its death, the giant Dreadnoughtus was still growing.

"There is no doubt that this is among the largest, if not the largest sauropod dinosaur yet recovered,  making it among the largest of all dinosaurs," said Patrick O'Connor, a paleontologist at Ohio University, Athens who was not involved in the discovery.

A paper describing the find was published Thursday in Scientific Reports.

Paleontologist Kenneth Lacovara of Drexel University first stumbled on the crumbled remains of Dreadnoughtus in southern Patagonia in February 2006.

"I found a little cluster of broken up bones and recorded it in my GPS," he told the Los Angeles Times. "But I also recorded 10 other sites on my GPS that morning."

Even when two of his team members began cleaning the bones later that day and revealed that they were in fact pieces of a giant femur bone, Lacovara was still blase.

"That's not unocommon," he said. "But then there was a tibia, and then a fibula, and at that point we were getting excited. Most sauropods are known by 10 bones. Four years later, we had 145."

Those bones, from two animals, will ultimately reside in the Museu Padre Molina in Rio Gallegos, Argentina, but for now, they are at Drexel University in Philadelphia and the Carnegie Museum of Natural History in Pittsburgh, where they were cleaned, analyzed, and photographed in 3D.

(The photographs are available to the public if you'd like to check them out.)

Paleontologists are particularly excited about the find because of  how well preserved the animals were, particularly the larger one. While the rest of us ooh and ahh over the giant size of this beast, the discovery of more than 45% of the Dreadnoughtus skeleton (minus the head) will allow scientists to better understand how these enormous animals loped about.

"Such complete specimens of large bodied sauropods are critical for better developing biomechanical models aimed at understanding how these largest of land-living organisms actually moved around," said O'Connor. 

Steve Salisbury, a scientist who studies dinosaurs at the University of Queensland in Australia, said this discovery also affects where researchers might look for other sauropod fossils.

"Dreadnaughtus shows we might expect to find similarly sized giant sauropods in Antarctica, which would be really exciting," he said. "There are indications emerging that there are also giant sauropods in Australia, so to get there, they must have moved through Antarctica, which was still connected to both landmasses at the time."

The area where the Dreadnoughtus were found was once a temperate forest that had both conifers and broad-leaf trees. These dinosaurs would have had to eat almost all the time to sustain their body mass, and Lacovara imagines them as eating machines, using their long necks to graze on a wide swath of plant life. 

There were several rivers that ran through the forest, and Lacovara thinks these two animals died when one of those rivers broke through its natural levee, turning what was solid ground into something like quicksand. In other words, these animals sank to their deaths.

But their untimely death was science's gain. "The rapid burial is responsible for the extraordinary completeness and beautiful preservation of their bones," Lacovara said. "We even see muscle scars on many of the bones, and that is because they got buried so fast."

http://www.latimes.com/science/sciencenow/la-sci-sn-gigantic-dinosaur-fossil-dreadnoughtus-20140903-story.html
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Posted by: Lin Kerns <linkerns@gmail.com>



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