Dinosaur luck

Apparently one of the reasons that the dinosaurs were at the top of the food chain for so long--135 million years, compare that to our own time on stage--may have been simple luck:

The researchers developed a database of hundreds of skeletal features of more than 60 dinosaurs and crurotarsans, as well as a new family tree of both groups, and used them to determine evolutionary patterns. They found much more disparity among crurotarsans’ morphological features — a much broader array of shapes and forms.

“The assumption is that the diversity or range of body forms is more or less proportional to the number of modes of life that they’d occupy,” Dr. Benton said. So the finding shows that the crurotarsans were more diverse in terms of their lifestyle, diet and habitat — they filled more ecological niches and were, if anything, the more successful of the two groups in the late Triassic. “The dinosaurs didn’t find a way to squeeze into the crurotarsans’ role,” he said.

But then at the end of the Triassic, for some unknown reason the dinosaurs survived while almost all the crurotarsans did not. “There was a certain amount of luck involved,” Dr. Benton said. “One group got pretty much wiped out and another group soldiered on and took off. The dinosaurs finally got their chance.”