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A Columbia University scientist today (Saturday, Nov. 9, 1996) announced 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 ruled 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, Professor 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," Professor 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 Professor Olsen, who is the Arthur D. Storke Memorial Professor at the University 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 Professor 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, Professor Olsen said. "We have lots of footprints from Triassic animals but very few skulls, and skulls give you a great deal more information about how the animals lived."
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, Dr. 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," Dr. 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 Professor 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, Professor Olsen said. It will also help scientists discover what happened on Earth to cause past - and perhaps future - mass extinctions, he said.
"Human activity is now producing changes on Earth that approach the magnitude and scale of the changes that occurred during these mass extinctions," Professor Olsen said. "Studying the fossil record gives us our only perspective on how catastrophic events on Earth can occur."
Professor Olsen found the skull, encased in sediments that had preserved it, in March 1995. The exact location has not been identified for reasons of public safety. The rock in which the skull was found is 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 Hartford Basin is just one of dozens that began to form in the Triassic about 235 million years ago. At that time, Pangea began to split apart, with the northwestern bulge of Africa separating from the U.S. East Coast, for example. Land near the edges stretched, cracked and subsided forming basins all along the East Coast, as well as in Texas, the Gulf of Mexico, Morocco, Europe and Greenland.
"They were essentially big catch basins into which sediments continually poured from 235 million years ago until about 180 million years ago in the Jurassic Era, when the nascent Atlantic Ocean had formed," Professor Olsen said. "Those sediments preserve an extraordinary record of an extraordinary period in Earth's history."
The conference at which Professor Olsen announced the fossil finding was the first of its kind devoted to a wide range of geosciences on Triassic-Jurassic rift basins. More than 40 scientists were expected to present research on such topics as the movements of Earth's crustal plates, the creation of landscapes, climate changes, evolution, and the formation of mineral and fuel deposits.
Sponsors of the conference were Lamont-Doherty; Columbia's Department of Earth and Environmental Sciences and its Office of the Vice Provost; Wesleyan University; Dinosaur State Park; the law firm of Murtha, Cullina, Richter & Pinney; Connecticut Natural Gas Corp.; Tilcon Connecticut, Inc. and the Iroquois Gas Transmission Corp.
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