BOZEMAN--A giant dinosaur nesting ground in South America, where a year ago scientists found the world's first fossilized dinosaur skin, will probably make headlines again this year, said a Bozeman, Mont., scientist connected with the project.
"This is the most incredible site I've ever seen," said Frankie Jackson, a researcher at Montana State University who accompanied a crew that just finished a five-week dig at the Patagonia site. "Nothing I've seen compares to this."
The site--called Auca Mahuevo after a nearby volcano--extends for about a mile to a mile and a half, Jackson estimated, and contained layer upon layer of eggs.
"You literally could not walk without stepping on egg shells," she said. "I was not prepared for the size of this at all."
Huge long-necked, plant-eating dinosaurs from the sauropod family nested there between 71 and 83 million years ago. The eggs--about six inches in diameter- were probably close to hatching when the site was buried by seasonal flooding, Jackson speculated. Scientists think the animals may have been nesting there for thousands of years.
The crew of American and Argentinean scientists unearthed more fossilized skin and embryos. Both are rare -- only seven other embryos have been found worldwide and identified as a particular dinosaur. Skin and other soft tissues rarely survive the passage of time because they don't fossilize.
"The eggs with bone had no skin, and the eggs with skin had no bones, so there's an unusual preservational process going on," Jackson said. The skin she described as reptilian and bumpy.
The second day out, the crew discovered a horned meat-eating dinosaur from the Abelisauras family. Buried in a lake deposit, the bones were articulated, or still intact. The animal's feet, which hadn't been found before, were still attached, Jackson said.
"It looked like the thing just fell over and died," she said.
An expert on egg shells, Jackson first became involved with the project last year. The expedition's leader, Luis Chiappe of the Los Angeles Museum of Natural History, asked her to do the research that ultimately proved the eggs belonged to dinosaurs rather than to birds or other reptiles.
Later Chiappe asked her to join the crew's return trip this February. Eleven years of working at the Museum of the Rockies' Egg Mountain field school near Choteau, Mont., is probably what qualified her for the job, she said.
Jackson mapped the location of more than 200 eggs during the 100-degree days and is analyzing their distribution. Some eggs she brought back to MSU to study in facilities she described as "second to none." MSU paleontologist Mary Schweitzer visited the site for a week and plans to do some follow-up research as well. All the fossils ultimately will be housed in a museum in Argentina.
"The hardest thing we still have to understand is how does a 30-foot dinosaur walk around in a nesting ground with such densely clustered eggs as this," Jackson said.
Did they incubate their eggs like birds or did they bury them like reptiles? The answer will tell paleontologists a lot about the animal's behavior, nesting strategy and biology. Museum of the Rockies paleontologist Jack Horner raised similar questions at Egg Mountain as he puzzled out how the duck-billed Maisaura dinosaurs must have cared for their babies.
Jackson said the Patagonia landscape reminded her of eastern Montana, except for exotic animals like the rhea, an ostrich-like bird.
"They ran across the desert. You could almost imagine they were theropod dinosaurs," she said.
Toward the end of the season, several reporters from CNN, the Associated Press, Newsweek and other news organizations joined the 13-member expedition that was sponsored, in part, by National Geographic.
Back home, Jackson said she's "wired" and ready to get to work. Although dinosaurs are fun to study, she's as fascinated by the region's geology and ancient soils as by the eggs and embryos.
She "fell in love" with geology after chaperoning her son Kaj and his cousins on a trip to Egg Mountain several years ago. Jackson began working at the site as a camp cook and later went back to school at the University of Montana.
Ironically, Kaj "hates dinosaurs and hates geology," Jackson laughed.
"He won't even go hiking with me unless I promise to not talk about rocks."