Where did T. rex come from? Fossil provides a clue Hans-Dieter Sues, chair of the Department of Paleobiology at the Smithsonian's National Museum of Natural History, holds a vertebra fossil from a new dinosaur, Timurlengia euotica, during a news conference in Washington, Monday, March 14, 2016. The image in the background is of the braincase of the Timurlengia euotica. (AP Photo/Susan Walsh)
Where did T. rex come from? Fossil provides a clue
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How did evolution produce a monstrous killer like T. rex? A fossil find in Central Asia is giving scientists a glimpse of the process.
 
T. rex and other tyrannosaurs were huge, dominant predators, but they evolved from much smaller ancestors. The new discovery from Uzbekistan indicates that this supersizing happened quickly, and only after the appearance of some anatomical features that may have helped the monster tyrannosaurs hunt so effectively.
 
The finding was reported by Hans-Dieter Sues of the Smithsonian's National Museum of Natural History in Washington, Stephen Brusatte of the University of Edinburgh in Scotland and others in a paper released by the Proceedings of the National Academy of Sciences.
 
They report finding bones of a previously unknown member of the evolutionary branch that led to the huge tyrannosaurs. This earlier dinosaur lived about 90 million years ago, south of what is now the Aral Sea. It looked roughly like a T. rex, but was only about 10 to 12 feet long and weighed only about 600 pounds at most, Sues said. T. rex grew about four times as long and weighed more than 20 times as much.
 
The discovery helps fill in a frustrating gap in the tyrannosaur fossil record. Before that gap, which began some 100 million years ago, the ancestral creatures were only about as big as a horse. Right after the gap, at about 80 million years ago, tyrannosaurs were multi-ton behemoths like T. rex. The new finding shows the forerunners were still relatively small even just 90 million years ago. So the size boom happened pretty quickly.
 
The inner ears of the newfound beast already had tyrannosaur features associated with good agility and hearing low-pitched sounds, which might have helped it detect prey or other animals at a distance. However, the creature lacked the massive, bone-snapping teeth and large sinuses found in T. rex.
 
The creature was dubbed Timurlengia euotica (TEE-mer-len-GEE-uh yoo-OH-tih-kuh). The name honors the ancient Central Asian ruler Tamerlane and the large inner ears of the beast. The fossils include a braincase and bones from the neck, back, tail, feet and hands. The creature wasn't a direct ancestor of T. rex, but it indicates what such ancestors looked like, Brusatte said.
 
The discovery helps scientists understand how "the (anatomical) parts got put together ... on the path to T-rex-hood," said Thomas R. Holtz, Jr. of the University of Maryland, who didn't participate in the study. And it suggests where to dig for more fossils to investigate the transition, he said.

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CRITICAL THINKING QUESTION
Why did huge dinosaurs evolve from smaller ancestors?
Write your answers in the comments section below


COMMENTS (7)
  • bodel1-col
    3/21/2016 - 10:26 p.m.

    Cause as they evolved they had more needs or needed more protein but their small bodies couldn't take out a predator that was bigger than them so they had to evolve and become bigger until the point of them not needing to evolve anymore.

  • Eric0221-YYCA
    3/22/2016 - 02:32 p.m.

    The T-rex ancestor fossil might have been able to provide clues about how the T-rex had evolved from their small ancestors to a big, super-sizing dinosaur which people would be finding clues about the T-rex ancestors. The people might have been finding clues about the T-rex ancestors from the small ancestor fossils which people would be able to find the clues from the ancestor fossils which people would find. The people might have been able to find clues about the T-rex ancestor that had evolved into other big dinosaurs that people would ever be seeing the dinosaur fossils. People might have been able to find evidence that the ancestors had been able to evolve into other big dinosaurs many years before the big dinosaurs had roamed the earth.
    Critical Thinking Question: Why did huge dinosaurs evolve from smaller ancestors?
    Answer: I know that huge dinosaurs evolved from smaller ancestors because the smaller ancestors had been able to evolve into huge dinosaurs which the huge dinosaurs had been able to evolve from.

  • kbeatty-cel
    3/28/2016 - 10:07 a.m.

    This leads to further and further knowledge of dinosaurs, something all people have a common interest in. With discoveries like these, everyone gains from having a better understanding of how the earth used to be. Who knows, this could be a leading discovery that could make the Jurassic Park movies a reality.

  • ShawnaWeiser-Ste
    4/06/2016 - 01:58 p.m.

    As time went on, the other animals began to grow bigger and bigger causing those dinosaurs to get bigger and easily take over its prey.

  • deangelod-pay
    4/25/2016 - 10:07 a.m.

    Huge dinosaurs evolve from smaller ancestors because of the fact that animals grow over time, and start to become larger and smarter and enhance as time goes by.

  • barringtond-pay
    4/25/2016 - 10:08 a.m.

    huge dinosaurs evolve from smaller ancestors because as time change the dinosaurs evolve so they can live better life better then the last one did probably at the time period everything probably increasing in size.

  • TaylorSeifert-Ste
    7/22/2016 - 10:58 p.m.

    Learning about dinosaurs makes me want to become an archaeologist. The information scientists are able to gather from ancient bones is incredible. More often than not, it's unbelievable to think that the world was once inhabited by such giant, deadly creatures. If I were ever to travel back in time to the dinosaur age, I'd hang with the herbivore dinosaurs; vegetarians just have a natural connection.

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