Were dinosaurs lucky?

Dinosaurs caught a lucky break.

Or so says years of prevailing wisdom among paleontologists over how dinosaurs rose about 200 million years ago from just another creature walking the earth to the planet's dominant life form.

That thinking, however, may be about to change.

A team of graduate students, including University of Chicago student and Crystal Lake native Nathan Smith, today are unveiling the discovery a new pre-dinosaur species that could reshape how scientists believe dinosaurs evolved and interacted with the world around them.

The previously unknown creature, named Dromomeron romeri (Dro-MO-mer-on RO-mer-eye), was discovered during an excavation last summer in the high desert of north central New Mexico.

The pre-dinosaur lived in the Late Triassic Period, about 210 million to 220 million years ago, a time marked by the rise of dinosaurs and disappearance of competing creatures.

But the location of its fossils alongside those of true dinosaurs shows the Dromomeron romeri lived with dinosaurs for millions of years, far longer than previously thought.

It also contradicts theories that dinosaurs quickly ascended to dominance because other creatures either died off through a mass extinction or simply couldn't keep up with the new kids on the block.

"These dinosaur precursors existed alongside dinosaurs for a long period of time, maybe 15 million years," Smith said. "It's clear now that dinosaurs didn't just get a lucky break and come about because other animals went extinct."

A paper about the discovery is being published as a cover story today in "Science" magazine.

Smith, a 1998 graduate of Prairie Ridge High School in Crystal Lake, is one of the piece's four authors and part of the team that unexpectedly discovered Dromomeron romeri at the Hayden Quarry, near the fossil-rich Ghost Ranch in New Mexico.

Based on fossils found so far, the team estimates the creature was about three feet long and 1½ feet tall at the hip, about the stature of a small- to medium-size dog.

"It would have been one of the smaller animals in the ecosystem," Smith said.

The name Dromomeron comes from the Greek word for running and Latin for femur, a combination Smith said represents their belief that the animal was fleet of foot. Romeri is a tribute to paleontologist Alfred Sherwood Romer.

Fossils of similar pre-dinosaurs, known as basal dinosauromorphs, have been found in areas of present-day Argentina, but the Dromeron romeri is the first of its kind discovered in North America.

Much about Dromomeron romeri -- what it ate, how it interacted with other animals -- is still unknown. As the team continues its work to answer those questions, Smith said it also may make discoveries about early dinosaur life.

"It's going to be really, really interesting because it is also tied to dinosaurs' development," he said.

Paul Sereno, the noted University of Chicago paleontologist and discoverer of 11 new dinosaur species, called the finds an important new addition to the understanding of dinosaur evolution.

"The most important fact rising from these quarries and intriguing, but isolated bones, is that some of the small proto-dinosaurs loved onward in time to overlap with true dinosaurs," he said.

Sereno was more cautious about whether the discovery changes previous theories about the rise of dinosaurs, calling the students' findings "more speculative."

"I think that story still holds, although one should expect differences on different sides of Pangaea," he said. "All in all, it is heartening to see new bones and evidence from this earliest part of the dinosaur era."

For now, Smith is back in Chicago, working toward his doctorate and putting in time at the Field Museum. He plans to return to the Hayden Quarry later this summer to continue his pursuit of history.

"It's going to be real exciting to see what else we've found," he said. "There's almost a lifetime of work that can be done there."