Lamont-Doherty Earth Observatory
Contact: Faye Yates
Byline: Hannah Fairfield
EMBARGOED FOR USE AFTER 12 NOON ON SATURDAY, APRIL 18, 1998
Four skulls of reptiles that lived about 200 million years ago have been discovered in a Pennsylvania construction site, a Columbia University scientist announced today (Saturday, April 18).
The skulls were among about 150 ancient bones found in Exeter Township, Penn, said Paul Olsen, a paleontologist at Columbia's Lamont-Doherty Earth Observatory, who identified the fossils. They represent a sizable addition to the scarce fossil record of the Triassic-Jurassic boundary 202 million years ago, when an as-yet unknown event wiped out more than half the Earth's land animals and set the stage for dinosaurs to dominate the
Olsen presented the findings today (Saturday, April 18) at a symposium in Philadelphia that is part of Dinofest, a month-long world's fair of dinosaurs, which ends April 26, hosted by the Academy of Natural Sciences.
Two of the three partial yet well-preserved skulls found in Exeter Township, Penn, and another one found in Pennsburg, Penn, belong to the genus Hypsognathus, a barrel-shaped herbivorous reptile that was about one foot long and proportioned like a modern-day groundhog. It has very distinctive horns on the sides of the skull, which make it easily identifiable. The third skull from Exeter is very recently discovered and has not been identified yet.
The findings are important because so little is known about the latest part of the Triassic Period. Skeletal remains were thought, by most scientists, to be very rare, says Olsen, who is the Arthur D. Storke Memorial Professor at Columbia. Olsen had a hunch that it wasn't the bones that were scarce, but the conditions for actually seeing them.
"We were looking at rocks at a construction site, and there was so much new, clean rock exposed after a rain," he says. "I thought there might be a lot more bones there than we had originally thought--and low and behold, once I really paid attention, there were."
The Exeter rock that encases the bones is a hard, slightly-baked mudstone. It is purple-brown, so the bright white of the bones stands out dramatically after rainfall. The site was also good for preserving footprints; paleontologists and amateurs had been collecting prints from the area for ten years. Two amateurs, Brian Hartline and Mike Szajna, both of Reading, Penn, found the skulls after Olsen told them he had begun to find bones at the site.
The first skull from Exeter was found in January; the second and third in April. "Ninety percent of the first skull was covered in dirt," Szajna says. "The only parts showing were two bony prongs. We knew the Triassic reptile Hypsognathus had prongs on its skull, so we called Paul and had him clean and identify it for us."
The skull from Pennsburg, Penn, was found by Joe Siske and Bob Hoffman, two amateurs who asked Dr. Peter Dodson of the University of Pennsylvania to look at it. Both Dodson and Olsen identify the fossil as most likely a Hypsognathus.
The three skulls from Exeter are being prepared by Dr. Hans-Dieter Sues, the curator of vertebrate paleontology at the Royal Ontario Museum in Toronto. "The greatest thing about this find is that it is in well-dated rock near the Triassic-Jurassic boundary," Dr. Sues says. "Now we have evidence that these animals lived right up to the boundary, which supports our ideas about a large-scale extinction there."
The fossils are critical pieces in the unsolved mystery of the mass extinction that occurred at the end of the Triassic Period. The extinction changed the course of evolution and allowed dinosaurs to dominate the Earth. "The Exeter site is especially important because the
fossils can be precisely dated from about 500,000 years before the mass extinction," says Olsen.
Because the sites are so newly discovered, little of the bone material has been prepared. Olsen suspects that the most important material remains to be identified.
Olsen has been a leading scientist in Triassic Period fossil discoveries in the East Coast region for several decades. He has previously found Triassic fossil sites in the Bay of Fundy, Connecticut, Virginia, and North and South Carolina
COLUMBIA UNIVERSITY IN THE CITY OF NEW YORK
DINOFEST: THE WORLD'S FAIR OF DINOSAURS
TRIASSIC-JURASSIC WORKING GROUP
NEWARK BASIN FOSSIL FOOTPRINT RESEARCH GROUP