Scientists Make Case for Ancient Gliding Reptile / Fossils of Two Creatures Have Been Discovered at

Jun 15, 03:24 AM

Current Headlines: By AJ HOSTETLER

About 220 million years ago, two reptiles gliding among the trees were apparently blown off course, falling and drowning in a nearby lake that is now the site of a quarry in southern Virginia.

Over time, their watery grave was covered and compressed by mud and sediment, undisturbed until recently brought to light by a Virginia scientist.

They left behind fossils, including of skulls, elongated ribs, spines, a bony tail, paired front and back legs, and tiny, pointed teeth, in the lake sediment that forms the shale of the Solite Quarry near the North Carolina border in Cascade, near Danville.

The bones were excavated from the deepest section of the lake in 1994 and in 2002 by paleontologist Nick Fraser of the Virginia Museum of Natural History in Martinsville, where one is on display.

Fraser found the second after spending time at the quarry with a school group. He had pulled a piece of rock from the wall of the quarry and was about to throw it away when sunlight spotlighted what appeared to be ribs. Then he saw a tail, and then a skull and the creature's torso.

"This has to be a gliding reptile. It's got these huge elongated ribs," he said. "I was really very surprised - that's just not the sort of thing you expect."

The 2002 finding led Fraser to see the similarity with the odd bones he had found eight years earlier. Fraser, museum colleague Alton Dooley, Tim Ryan of Pennsylvania State University and Paul Olsen of Columbia University describe the gliding pair in the June issue of the Journal of Vertebrate Paleontology.

The gliders are named Mecistotrachelos apeoros for their exceptionally long necks, which made them aerodynamically unstable. Fraser believes they are related to the protorosaurs, a group of extinct reptiles characterized by a long neck.

M. apeoros looks like a giant lizard crossed with an ungainly dragonfly, with hooked front and hind feet to grasp branches as it plunged among the trees. Its body was about the size of a blue jay, about 8 inches long with a tail at least half as long. The neck itself measures a little more than 2 inches, Fraser said.

Fraser said the gliders probably foraged on insects as they scuttled up tree trunks. Their elongated ribs supported winglike membranes about 7 inches in spread. The membranes were too fragile for flapping, so the gliders made their way by veering from branch to branch, he said.

University College London paleontologist Susan Evans said the researchers made a strong case for the glider, noting that there are two other Triassic gliding reptiles.

The description of the gliders is bolstered by CT scans, which allow paleontologists to excavate digitally when they can't physically free the fossilized bone from the rock, said paleontologist Hans Sues of the Smithsonian Institution's National Museum of Natural History. "CT scanning is really a godsend," he said.

The Solite Quarry is renowned as the only location in the world where complete insect specimens from the Triassic Period are found in abundance. Some are so well-preserved that wing hairs on insects the length of the thickness of a dime can be seen.

Olsen made the first fossil discoveries at Solite Quarry while trolling the pit as a geology student at Yale University in 1975. Within a few years, he had unearthed about 300 reptiles, dozens of fish and hundreds of insect fossils, all from the Triassic Period.

The Triassic roughly covers the time between 200 million and 250 million years ago, when the Earth's continents were united in one giant supercontinent called Pangea. At the time, the land area of modern-day Virginia was just north of the equator in a humid tropical environment. A few millions years later, the single continent broke up, eventually settling into the drifting continents and oceans that exist today.

Fraser and other scientists from the Virginia museum have studied the Solite Quarry since 1990, where they also found the state's only dinosaur footprints.

Contact A.J. Hostetler at (804) 649-6355 or ahostetler@timesdispatch.com.

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