Scientists have found the fossil remains of a dinosaur sitting on a nest of eggs like a mother hen, a spectacular discovery that suggest birds inherited this behavior from dinosaurs.
The nine-foot-long creature, which resembled a wingless ostrich with a long tail and arms, died in Mongolia's Gobi Desert some 70 million to 80 million years ago. It may have been engulfed in a giant sandstorm.The discovery is astonishing, said dinosaur expert David Weis-hampel of the Johns Hopkins University School of Medicine.
Scientists didn't know that dinosaurs brooded their nests, he said. And the fossil is "amazingly beautiful," he said.
"It's just there. Without any imagination at all you can imagine this critter sitting on a nest."
Jack Horner, curator of paleontology at the Museum of the Rockies in Bozeman, Mont., said he considered it "one of the two best specimens of dinosaur fossils ever found" because it reveals behavior.
"We've had nests and babies and all sorts of things, but we had never had the direct evidence of the parent with the eggs," Horner said. "By far this is the strongest evidence of some kind of parental attention."
The find is reported in Thursday's issue of the journal Nature by researchers at the American Museum of Natural History in New York, George Washington University in Washington, D.C., and the Mongolian Academy of Sciences in Ulaan Baatar, Mongolia.
The dinosaur is called an oviraptor. Mark Norell of the museum, lead author on the paper, said it's no surprise to him that oviraptors brooded because they were so closely related to birds.
Paul Sereno, an associate professor of paleontology at the University of Chicago, said that before the fossil was found scientists could only guess that oviraptor brooded.
"Here we have a smoking gun," Sereno said.
Although birds had appeared by the time the oviraptor died, the finding provides the strongest evidence yet that birds inherited brooding from dinosaurs, Norell said.
That's because birds and oviraptors evolved from a common dinosaur ancestor, Norell said. And since the brooding behavior is found in oviraptors and the birds, it was probably present in that common ancestor, he said.
Just when that ancestor lived is not known, but it came before the first known bird, Archaeopteryx, which lived some 140 million years ago, Norell said.
The scientists found the oviraptor fossil in 1993 and realized immediately that it was important, Norell said. The dinosaur and the nest were removed in a single 400-pound block of sandstone to show how they were found, because "otherwise people wouldn't believe us," Norell said.
The oviraptor is "in the exact same position as if you looked at a chicken sitting on a nest," Norell said.
He and colleagues uncovered 15 oviraptor eggs in the nest and concluded that it probably contains about 22, a typical number. The eggs are neatly laid out in a circle, with the thinner ends pointing to the outside.
It's not known whether the recovered oviraptor is male or female, Norell said.