An enigma for decades, a giant dinosaur known only for its brawny arms actually towered over the local tyrannosaurs, paleontologists report. It also ate plants and perhaps sported a surprising sail or hump on its back.

The dinosaur Deinocheirus mirificus (which means, essentially, "terrible hands that look peculiar") had been a stubborn fossil enigma for nearly 50 years.

Nothing except the dinosaur's eight-foot-long arms, tipped in three huge claws, and a handful of other bone fragments had ever been found.

But at the annual Society of Vertebrate Paleontology conference held in Los Angeles last week, Korea Institute of Geoscience and Mineral Resources paleontologist Yuong-Nam Lee presented a wealth of new fossils that make Deinocheirus stranger than anyone had previously imagined.

A nursery of bizarre-looking dinosaurs known as therizinosaurs has been found in the Gobi Desert in Mongolia.

The nesting colony contained at least 17 clutches of eggs.

"Not only is this the largest colony of nonavian theropods, but this is the best documented site," said study co-author Yoshitsugu Kobayashi, a vertebrate paleontologist at Hokkaido University in Japan, who presented the findings here at the 73rd annual Society of Vertebrate Paleontology conference.

The finding suggests the odd little creatures were social animals. Read more...

Paleontologists on Wednesday unveiled a new dinosaur discovered four years ago in southern Utah that proves giant tyrant dinosaurs like the Tyrannosaurus rex were around 10 million years earlier than previously believed.

A full skeletal replica of the carnivore — the equivalent of the great uncle of the T. rex — was on display at the Natural History Museum of Utah alongside a 3-D model of the head and a large painted mural of the dinosaur roaming a shoreline.

It was the public's first glimpse at the new species, which researchers named Lythronax argestes (LY'-throw-nax ar-GES'-tees). The first part of the name means "king of gore," and the second part is derived from poet Homer's southwest wind. Read more...