The "not-an-allosaurus" is emerging from a plaster shell right before the eyes of visitors at Dinosaur National Monument outside Jensen, Uintah County.
Bone by bone, paleontologist Dan Chure will study the creature over the next year. In the process of describing it, he'll attempt to answer this Jurassic brain teaser: Exactly what kind of dinosaur is this? Chure knows what the dinosaur is not: It is neither an allosaurus nor ceratosaurus nor any other meat-eating dinosaur now known. Its identity and place in dinosaur evolution awaits Chure's careful study after associates free it from a 6,700-pound rock tomb."It is about 15 to 20 feet long and virtually complete from the tip of its tail to the end of its neck," Chure said. "Everyone was really crossing their fingers that we would end up with the skull, but we weren't that lucky."
So far. Chure remains hopeful the skull will surface some day. But "even if we don't find it, it is one of the most complete dinosaurs ever found in the Morrison form-a-tion."
The paleontologists' work to bring the specimen to the visitors center has ranged the gamut of skill and technology - from use of brute-force jack hammers to high-tech microscopes.
"It's real exciting," said Ann Elder, fossil preparer who managed excavation of the dinosaur with co-worker Scott Madsen and volunteers. "Now that it is re-emerging day by day, (we're seeing) the bones that we exposed in the field but then had to cover up to keep them from being hurt by rain or weather. It's kind of like seeing an old friend."
The block of rock encasing the dinosaur sits between the monument's cliff face and the exhibit inside the visitors center, where visitors can glimpse the paleontological work in action.
More than three years ago, a bit of foot protruding from sandstone in the Salt Wash member of the Morrison Formation gave away the dinosaur's final resting spot. Paleontologists carefully uncovered enough of the skeleton to be sure of its dimensions and packed the surrounding rock block in plaster.
In October, a helicopter ferried the remains from the precarious slope where it was found to the monument.
Because the skeleton is so well-preserved, Chure expects to learn much that can be applied to other types of dinosaurs. For example, paleontologists have found a "wish-bone" with remains of some other carnivorous dinosaurs, but the bones have been displaced. That's led to debate about what the bones were and how widespread they were among dinosaurs, Chure said.
The wishbone is in place in the not-an-allosaurus, Chure said.
"It is sitting in the exact place it was when the dinosaur was alive, and it hasn't been moved or jumbled or disconnected from the other bones," Chure said. "This shows that it is a wishbone, and that the feature is more widespread in meat-eating dinosaurs than thought."
The not-an-allosaurus was found in the first year of a three-year survey conducted by a consultant for the National Park Service. In the course of the survey, the number of known fossil sites in the park increased from five to about 400, Chure said.
In addition to the not-an-allosaurus, the Morrison formation, which was deposited from 152 million to 142 million years ago, is yielding other clues about prehistoric life that once populated Utah. Perhaps most startling are the dozen or so tiny teeth found by screenwashing clay and mud rock.
The teeth, which are 2 millimeters to 3 millimeters tall and have serrated edges, appear to belong to miniature, meat-eating dinosaurs about the size of turkeys, Chure said. They provide the first reported evidence of small, meat-eating Jurassic dinosaurs outside of Europe and Asia, where two or three small dinosaur skeletons have been found.
"There is room in the food chain for predators of all sizes," Chure said. "While these small dinosaurs didn't feed on the big ones, they probably feed on lizards, frogs and hatchlings of other species."
Chure is using a scanning electron microscope at Brigham Young University to study the teeth. Features revealed by the microscope indicate some of the teeth came from troodonts, a meat-eating Jurassic dinosaur that ranged from 2 feet to 6 feet in height and up to 10 feet in length.
Paleontologists also have found fossilized impressions of a dozen or so frogs in the past several years, providing "more complete frog specimens than anywhere else in the world," Chure said.
They've also found one of the best Jurassic-era lizard skulls in the world, dozens of small mammals and five or six complete salamander skeletons, Chure said.
A lot of these bones are so small they can be mounted on the head of a pin, Elder said. Others are even smaller and must be left partly exposed in rock and examined under a microscope.