The Dinosaur That Peacefully Grazed
Friday, November 16, 2007
Could an elephant-size dinosaur with a skull so thin that a karate chop would have split it in two, teeth it shed once a month and a brain that, yes, was the size of a walnut, ever be considered one of evolution's success stories?
Paul C. Sereno thinks so.
The University of Chicago paleontologist yesterday unveiled Nigersaurus taqueti, a strange creature that is helping rewrite theories about how long-necked, plant-eating dinosaurs looked and behaved.
Nigersaurus appears to have spent a lifetime with its head in a hangdog position. Using a broad, tooth-filled mouth, it grazed on ferns and horsetails growing at most a couple of feet high. It couldn't even raise its head to horizontal. Getting at trees was out of the question.
Many other dinosaurs -- including the more famous and less bizarre Diplodocus -- probably behaved similarly, using their long necks as ground-mowing booms, not treetop cherry pickers, Sereno believes.
"It took an extreme dinosaur to open our eyes to this cow-like behavior," he said yesterday at the National Geographic Society's headquarters in the District, where a reconstruction of Nigersaurus was mounted. "It is sort of silly to think that something wasn't doing this. But we had missed the cows of the Mesozoic."
Other paleontologists agreed that the new dinosaur will further dispel the notion that long-necked dinosaurs were the prehistoric equivalent of giraffes, holding their heads high overhead.
"It would be hard to imagine a more compelling argument against" that view, said Kent A. Stevens, a computer scientist at the University of Oregon who has done extensive research on dinosaur posture.
Matthew T. Carrano, the curator of dinosaurs at the Smithsonian Institution, doubts there will be many arguments against a bovine dinosaur. There have been too many other strange-but-true discoveries in recent years.
"What we are seeing is something that we just didn't know about before. We are coming to accept the fact that this is going to be a regular thing for us," he said.
Sereno, who is also an explorer-in-residence at the National Geographic Society, discovered Nigersaurus in the Sahara in the North African country of Niger in 1997.
It was excavated over three years by a large team that included two paleontologists from the University of Niamey, in Niger, who attended yesterday's unveiling of a life-size model. Parts of five animals were found, with the skeleton 80 percent complete.