New 230mn-yr-old predator 'dawn runner' discovered in South America

Washington, Jan 14 (ANI): Experts have announced the discovery of a dinosaur that roamed South America approximately 230 million years ago and have dubbed it the 'dawn runner'.

"It really is the earliest look we have at the long line of meat eaters that would ultimately culminate in Tyrannosaurus rex near the end of the dinosaur era," said Paul Sereno, University of Chicago palaeontologist and National Geographic Explorer-in-Residence.

"With a hike across the valley, you literally walk over the graveyard of the earliest dinosaurs to a time when they ultimately dominate," said Ricardo Martinez of Argentina's National University of San Juan.

"Radioisotopes-our clocks in the rocks-not only placed the new species in time, about 230 million years ago, but also gave us perspective on the development of this key valley," said Paul Renne, director of the Berkeley Geochronology Center in California.

"About five million years of time are represented in these layers, from one end to the other."

'Dawn runner' Eodromaeus lived alongside Eoraptor, a similar-sized, plant-eating dinosaur, whose descendants would eventually include the giant, long-necked sauropods.

Eodromaeus, with stabbing canine teeth and sharp-clawed grasping hands, is the pint-sized precursor to later meat-eaters called theropods, and eventually to birds.

"We're looking at a snapshot of early dinosaur life. Their storied evolutionary careers are just unfolding, but at this point they're actually quite similar," Sereno said.

The authors logged thousands of fossils unearthed in the valley to find, as Martinez remarked that. "dinosaurs took their sweet time to dominate the scene."

"The story from this valley suggests that there was no single advantage or lucky break for dinosaurs but rather a long period of evolutionary experimentation in the shadow of other groups," Sereno said.

"The dawn of the age of dinosaurs," Martinez remarked, "is coming into focus."

The findings appear in the Jan. 14, 2011 issue of the journal Science. (ANI)