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標題: The most complete giant titanosaurs 60 tons "Dreadnoughtus"  
 
oviraptor (偷蛋龍)
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The most complete giant titanosaurs 60 tons "Dreadnoughtus"

Enormous New Dinosaur as Formidable as Its Namesake Battleship

At 60 tons, the newly named "Dreadnoughtus" is the most complete of the giant titanosaurs yet found.


Ken Lacovara is shown with 22 tail vertebrae (out of 32 collected) of the massive sauropod Dreadnoughtus schrani. The dinosaur has the largest calculable weight of any known land animal.

Photograph by Robert Clark, Excel Magazine Drexler University


After nine years of excavation and study, paleontologists have unveiled one of the largest creatures ever to walk the Earth. The most complete skeleton of a giant titanosaur will provide new insights into how these giants lived large.


The new dinosaur is named Dreadnoughtus schrani, a reference to the armored battleship and a tribute to the dinosaur's perceived fearlessness. Details on the dinosaur are announced Thursday in the journal Scientific Reports.


Art: Emily M. Eng, NG Staff. Source: Matthew C. Lamanna, Carnegie Museum of Natural History

In life, Dreadnoughtus would have been about 86 feet (26 meters) long and weigh nearly 60 tons, heavier than a Chieftan tank, Drexel University paleontologist Ken Lacovara and colleagues calculate. That's so big, the scientists write, that adults of the species would have been "nearly impervious to attack" by predators that stalked the same floodplains between 84 million and 66 million years ago.

Among the largest of dinosaurs, titanosaurs like Dreadnoughtus were hefty herbivores with tiny heads, long necks, and tapering tails. This body type marks titanosaurs as part of a group called sauropods, to which classic dinosaurs such as Apatosaurus also belonged. Sauropods spent their days feeding high and low, plucking greens from patches of ferns and trees alike, as they browsed the prehistoric salad bar.

What makes Dreadnoughtus a remarkable new addition to this prehistoric family is the amount of material recovered from the dinosaur. The remains, representing two individual animals, include both the humerus and femur of Dreadnoughtus, and Lacovara and colleagues used the circumference of these bones to estimate the dinosaur's weight.

So far, Lacovara says, "Dreadnoughtus has the largest calculable mass of any land animal."


Detail of the top of a Humerus from a Souropod sound in Patagonia.
The humerus, or upper arm bone, of Dreadnoughtus shows muscle scarring.

Photograph by Robert Clark, Excel Magazine Drexler University


A Big Find

At first, though, Dreadnoughtus didn't seem so impressive. "In 2005, we were prospecting in the desert [of southern Argentina]," Lacovara says, "and the first day of that field season I found a collection of bones." They just looked like a pile of fragments, but when Lacovara and collaborators returned to the site, they started uncovering big limb bones.

"By the end of the day we had ten bones exposed," Lacovara says. "At that point we were pretty excited." Four field seasons later, the team had excavated 145 bones.

Altogether the bones represent about 45 percent of a complete skeleton, and because some of the bones have mirror images on the other side of the body, Lacovara and colleagues were able to reconstruct about 70 percent of a Dreadnoughtus skeleton. The best large titanosaur find previously, Futalognkosaurus, was only about 27 percent complete.

"Now we can start talking intelligently about the body proportions of these giant titanosaurs," says Western University of Health Sciences paleontologist Mathew Wedel.


Dreadnoughtus schrani on a football field for scale.
Emily M. Eng, NG Staff.


And Dreadnoughtus could have grown even bigger than the new estimate. "Since the authors provide data that illustrate that Dreadnoughtus was still growing when it died," says Macalester College paleontologist Kristi Curry Rogers, "we can be fairly certain that there were other heavier dinosaurs out there."

Mysterious Lives

But size isn't everything. "If we want to really begin to understand how these big dinosaurs grew, and how long it took them to reach their massive sizes, these are the perfect kinds of data to begin with," Curry Rogers says. Having two individuals is a good start, she says, but scientists will need to find more of the dinosaurs to begin piecing together their lifestyles.

"There are so many fundamental things we don't know about sauropods," Lacovara says, such as the arrangement of their muscles and how they moved. Turning to muscle scars on the bones of Dreadnoughtus, Lacovara and others are figuring out the dinosaur's muscle anatomy and how those soft tissues translated to movement.

This is just the sort of effort other paleontologists are hoping to see. "It's all about building toward a more complete picture of the living animal," Wedel says.



The 5.6-foot (1.7-meter) scapula of Dreadnoughtus is the longest yet reported for any titanosaur.
Photograph by Robert Clark, Excel Magazine Drexler University

For now, though, Lacovara is glad to see Dreadnoughtus finally emerge after all the years of fieldwork and study. "This is like Christmas and my birthday and my wedding combined."
http://news.nationalgeographic.c ... noughtus-argentina/

[ 本帖最後由 oviraptor 於 2014-9-4 10:23 PM 編輯 ]




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2014-9-4 09:56 PM#1
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oviraptor (偷蛋龍)
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Dreadnoughtus schrani



圖片附件: Dreadnoughtus schrani.jpg (2014-9-4 11:13 PM, 55.91 K)





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2014-9-4 11:13 PM#2
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超巨草食恐龍化石出土 「無畏龍」重過737客機

■「無畏龍」超級巨型,長26米、重65噸。

美國科學家在阿根廷巴塔哥尼亞南部,發現一副超級巨型草食恐龍化石,體形較暴龍大七倍、比一架波音737飛機還要重。


名為「無畏龍」(Dreadnoughtus schrani)的新發現品種恐龍化石,是德雷克塞爾大學教授拉科瓦拉領導的團隊,於2005至09年間挖掘出土,相信約7,700萬年歷史。  


比暴龍大7倍 沒天敵可抗衡

科學家推算牠身長26米、重65噸,比一架波音737客機還要重,較暴龍大七倍,相信是全球最大陸上動物,亦是至今發現最完整的草食恐龍骸骨。但科學家認為牠在死前仍未完成發育,推算牠的成年身形比估計還要大。
拉科瓦拉指,由於牠的身形龐大,沒有天敵與牠抗衡,故將牠命名為無畏龍。「牠有一個房子般大的身體、12隻大象的重量及可用作武器的九米長尾巴,立於不敗之地。」
英國《每日電訊報》




2014-9-12 09:10 AM#3
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c7 (Cristiano Ronaldo)
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版主究竟是最長的恐龍,還是最重呢?



2014-9-14 08:54 PM#4
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QUOTE:
原帖由 c7 於 2014-9-14 08:54 PM 發表
版主究竟是最長的恐龍,還是最重呢?
不算是最長,應該是最重,而且也是最完整的




2014-9-18 03:05 AM#5
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