U of C dinosaur prof helps dig up early meat-eater

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Updated: May 4, 2011 4:46AM

It’s lanky, fast and about the size of an average small pet dog.

To children who’ve grown up with “Jurassic Park” and the Field Museum’s Tyrannosaurus Rex, it might not look like much.

But at 230 million years old, the Eodromaeus, or “dawn runner” — discovered in Argentina by a team including University of Chicago paleontologist Paul Sereno — is the earliest known meat-eating dinosaur.

Four feet long from the tip of its nose to the end of its long tail, the near-complete 10-to-15 pound Eodromaeus was one of two matching skeletons dug up in a desert area at the foothills of the Andes in 1996.

But it took a decade and a half of painstaking study to distinguish the meat-eater from its vegetarian cousin the Eoraptor, Sereno said as he unveiled the discovery Thursday afternoon.

“A discovery like this is very rare,” he said, “It might take another decade to find something as significant.”

The Eodromaeus’s stabbing canine teeth and sharp grasping clawed hands identified it as a distinct species and a forerunner of a long line of meat-eating dinosaurs that culminated in the T. Rex 165 million years later, according to a study published in the journal, Science.

It likely ate the young of other prehistoric reptiles and would have been “nasty — something to steer clear of,” according to Sereno, who fielded questions on his research from students at Haughan Elementary School in an online video presentation Thursday.

The name “dawn runner” doesn’t refer to the critter’s preference for early-morning jogs, but its speed and its place at the dawn of the dinosaur era.

Its discovery in the so-called “Valley of the Moon” in north-west Argentina supports the growing theory that dinosaurs took millions of years to establish themselves as dominant over other species. And it leaves only a two-or-three million year window for earlier dinosaur remains to be unearthed, Sereno said.

But the significance of the remains appeared to be lost on customs officials who believed the case Sereno used to transport the skeleton back to his lab may have contained a live animal and summoned animal control officers, he said.

“It’s been dead a long time,” he told them.