Scientists from Carnegie and Smithsonian museums and the University of Utah have introduced the world to a sharp-clawed, 500-pound, bird-like dinosaur that roamed the Dakotas about 66 million years ago, during the same time as the Tyranosaurus Rex.

The 11.5-foot-long creature "was a giant raptor, but with a chicken-like head and presumably feathers... it would be scary as well as absurd to encounter," said University of Utah biology postdoctoral fellow Emma Schachner, co-author of a new study of the dinosaur published online in PLOS ONE, a journal of the Public Library of Science.

The study's lead author, Matt Lamanna of the Carnegie Museum of Natural History in Pittsburgh, noted he and his research colleagues "jokingly call this thing the 'chicken from hell,' and I think that's pretty appropriate."

The beaked dinosaur is formally named Anzu wyliei, inspired by Anzu, a bird-like demon in Mesopotamian mythology, and Wylie Tuttle, the dino-loving grandson of Lee Foster, chairman of the Carnegie Museums of Pittsburgh's board of trustees.

The partial remains from three of the same dinosaur species, which nearly completed a full skeleton, were unearthed from the Hell Creek rock formation in North and South Dakota, previously known for its abundant collection of T-Rex and Triceratops fossils.

A full cast of the Anzu wyliei bones is now on display at the Carnegie Museum.

The Anzu is "one of the youngest oviraptorosaurs known, meaning it lived very close to the dinosaur extinction event," which scientist generally believe was caused by an asteroid that struck the planet approximately 65 million years ago, said Schachner.

With its large, sharp claws, the Anzu, weighing an estimated 440 to 660 pounds and living on a wet floodplain, was apparently an omnivore that mainly ate vegetation, but also preyed on small animals as well as eggs.

Like many dinosaurs discoveries, the Anzu fossils were some time ago. But, it required years of painstaking research before the fossils could be unveiled and written-up in a formal scientific description.

In fact, the discovery of the chicken-headed animal was first announced within the scientific community in 2005.