Dinosaurs

University of Chicago researchers have discovered bones of two massive meat-eating dinosaurs in Africa. Kryptops palaios, or "old hidden face," was named for a horny covering over its face. Eocarcharia dinops, or "fierce-eyed dawn shark," had razor-sharp teeth and a bony brow. Both were about 25 feet long and 7 feet tall, researchers reported last week in the journal Acta Palaeontologica Polonica.

The auctioneer gazed out at the audience, knowing this was the moment they'd waited for. Next up, he said, was lot No. 23 -- a "wonderful, exceptional, 66-million-year-old Tyrannosaurus rex skeleton known as Samson." He gestured to the ferocious-looking skull sitting on a stand to his left. "There she is," he said. The people who had gathered in the elegant gallery at the Venetian hotel gasped. Samson is one of the three most complete T. rex specimens ever discovered, possessing the most intact skull in existence.

Soft, organic material discovered inside a Tyrannosaurus rex fossil that scientists believed was 70-million-year-old dinosaur tissue may have been nothing more than ordinary slime, scientists said in a study published Wednesday. Researchers reported in the online journal PLoS ONE that bacterial colonies infiltrating tiny cavities in the bones long after the dinosaurs died may have naturally molded into shapes resembling the tissues they replaced.

The bluffs and hills on the outskirts of this mountain biking hub were as red as a sunburn and barren, save for a few juniper trees and clumps of rabbit brush. As I hiked up a gentle slope to a flat stretch of sandstone, I saw them -- bigger and more clearly defined than I had expected. Dinosaur tracks. I crouched by the gnarly three-toed prints and ran my fingers along the curve of the claw and pressed my palm inside the hubcap-size impression.

A new study of one of the earliest feathered dinosaurs suggests it may have had upper and lower sets of wings, much like a biplane. The dinosaur, known as \o7Microraptor gui, \f7was originally described in 2003 by Chinese researchers as having aerodynamic feathers on both its arms and legs, arranged in flight one behind the other, like a dragonfly.

The asteroid that smacked Earth 65 million years ago wiped out the dinosaurs and paved the way for mammals to dominate, but it took 10 million to 15 million more years for the ancestors of today's mammals to really take over, scientists said Wednesday. While some mammals seized the day and diversified after the asteroid crashed off the Yucatan Peninsula causing a mass extinction, they largely were evolutionary dead-ends, scientists said.

Foghorn Leghorn would be proud. The cantankerous Loony Tunes rooster and his brethren appear to be the closest living descendants of the ferocious \o7Tyrannosaurus rex\f7 that ruled the world of dinosaurs. That's the conclusion of a team of researchers who analyzed a remarkable 68-million-year-old sample of \o7T. rex\f7 tissue. It began two years ago when paleontologist Mary H.

The remains of a birdlike dinosaur as tall as the formidable \o7Tyrannosaurus rex \f7have been found in China, a discovery that indicates a more complicated evolutionary process for birds, scientists reported Thursday in the journal Nature.

A game of asteroid billiards may have set in motion the chain of events that wiped out the dinosaurs 65 million years ago, a team of researchers announced this week. According to the Czech-American team, the giant rock that hit Earth was probably a fragment from a collision in the asteroid belt about 100 million years earlier.

The vicious little dinosaur velociraptor was a feathered fiend, said scientists who found evidence of quills on this well-known meat-eater's forearm. In research published Friday in the journal Science, paleontologists said a forearm bone of velociraptor found in Mongolia's Gobi Desert retained structures, or quill knobs, where a series of feathers were anchored to the bone with ligaments.