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Nothronychus (Getty Images)


Nothronychus (Greek for "sloth claw"); pronounced no-throw-NIKE-us


Southern North America

Historical Period:

Middle-Late Cretaceous (90 million years ago)

Size and Weight:

About 15 feet long and 1 ton



Distinguishing Characteristics:

Long arms with long, curved claws; possibly feathers


About Nothronychus:

Demonstrating that surprises can lay in store for even the most experienced dinosaur hunters, the type fossil of Nothronychus was discovered in 2001 in the Zuni Basin on the New Mexico/Arizona border. What made this find especially significant is that Nothronychus was the first dinosaur of its kind, a therizinosaur, to be dug up outside Asia, which has prompted some quick thinking on the part of paleontologists. In 2009, an even bigger specimen--which has been assigned its own species under the Nothronychus umbrella--was unearthed in Utah, and later came the discovery of yet another therizinosaur genus, Falcarius.

As with other therizinosaurs, paleontologists speculate that Nothronychus used its long, curved claws much like a sloth, to climb trees and gather vegetation (although they're technically classified as theropods, the therizinosaurs seem to have been strict plant-eaters, or at the very least pursued omnivorous diets). However, additional information about this obscure, pot-bellied dinosaur--such as whether it sported primitive feathers--will have to await future fossil discoveries.


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