Photograph: A reconstruction of the 212-million-year-old carnivore.

Photograph: Paul Olsen. Photo Credit: Sally Savage.

By Faye S. Yates

A Columbia scientist announced Nov. 9 the unexpected discovery in Connecticut of an ancient crocodile-like reptile--the first ever found in North America--that lived millions of years before dinosaurs roamed the Earth. Paul Olsen of Columbia's Lamont-Doherty Earth Observatory said he had found the skull of the 212-million-year-old unnamed carnivore exposed in the cut of a roadside in the town of Cheshire.

The paleontologist said that the three-inch skull belonged to a delicately boned, 20-inch-long reptile that resembled a small crocodile but ran on long, slender legs. Only one other similar skull is known to scientists: an animal called Erpetosuchus, discovered in 1894 in Elgin, Scotland.

The reptile lived during the Triassic Era, between 202 million and 252 million years ago, more than 80 million years before Velociraptor roamed the Earth and more than 125 million years before Tyrannosaurus rex reigned. At the time, Earth's climate was warmer and all of the Earth's land was a single mass called Pangea, which later broke apart into today's familiar continents. The animals found in Scotland and Connecticut, now on different and widely separated continents, may be the same genus but certainly had a common ancestor, Olsen believes.

The find is particularly important, he said, because so little is known of life during the Triassic. He announced the finding at a scientific conference at Dinosaur State Park in Rocky Hill, Conn., not far from where he found the skull.

"The fossil was just lying out there waiting to be seen," Olsen said. "The bone is white and the rock is reddish-brown, but there were a lot of white flecks here and there in the rock that are not bone. I walked away from it several times, thinking about it. It took about an hour to convince myself that it was a bone. It looked not too different from fossilized roots, which are also white. But then I noticed a tiny tooth, and roots don't have teeth. I knew then that it was bone, but I didn't realize at first that it was a nearly complete skull."

The fossil adds to the scarce collection of clues to the still-unexplained mass extinction about 200 million years ago that wiped out nearly half the species on Earth. The extinctions reshuffled the evolutionary deck and set the stage for dinosaurs to become the planet's dominant life form, said Olsen, who is the Arthur D. Storke Memorial Professor at Columbia and a senior research scientist at Lamont-Doherty, Columbia's earth sciences research center in Palisades, N.Y. The find is being studied jointly by Olsen, Hans-Dieter Sues, curator of vertebrate paleontology at the Royal Ontario Museum in Toronto, and Mark Norrell, curator of vertebrate paleontology at the American Museum of Natural History in New York City, where the skull is being prepared. Early dinosaurs existed during the Triassic, but they were small and lived in a largely non-dinosaur world of fish, amphibians, small mammals and other non-dinosaur reptiles, Olsen said.

The skull comes from a non-dinosaur reptile that competed with early dinosaurs for food; possibly it hunted and was hunted by dinosaurs, too. It was an active predator with a large head and a long, toothed snout to subdue prey, Sues said. It ran on all four legs and was cold-blooded, unlike early dinosaurs, which were warm-blooded and ran on two legs.

"These little creatures are virtually unknown," Sues said. "Life in the Triassic Era in general is a great blank, particularly in the Northeast. This is an absolute first for North America and absolutely unexpected. There is a myth that the East Coast is poor in fossils, but Paul is one of the few people who has believed that this region has its paleontological treasures. It just take more patience and energy to find fossils on the East Coast, but they are there."

Animals like the one Olsen found thrived before 202 million years ago, but they did not survive afterward into the Jurassic Era. Dinosaurs did, however, perhaps taking advantage of the absence of competition. In just 25,000 years--a flash in evolutionary time--dinosaurs grew rapidly, their footprints doubling in size. They diversified and became the dominant life on Earth until 65 million years ago, when another catastrophic event--most likely an asteroid collision--caused their extinction and set the stage for the rise of mammals.

New fossils from the Triassic provide rare new information that will help scientists figure out the evolutionary adaptations that allowed dinosaurs to prevail while the others died out, Olsen said. It will also help scientists discover what happened on Earth to cause past--and perhaps future--mass extinctions, he said.

Olsen found the skull, encased in sediments that had preserved it, in part of the Hartford Basin, the geological name for a 15-mile-wide depression in the Earth's crust that extended along what is now the Connecticut River Valley from the northern Massachusetts border to New Haven. The