"What this seems to imply is that, even from fairly early in their history, dinosaurs were entirely bipedal and weren't using their forearms to support themselves in any way," said paleontologist Tom Holtz of the University of Maryland, who was not involved in the research. "Because of that, the hands could specialize as weapons, to grab on to a struggling animal or to fight with other dinosaurs," he said. The handprints are among more than 1,200 dinosaur tracks deposited in mud along the shores of an ancient lake, then buried and fossilized. Most of the tracks are similar to ones found at other sites, said paleontologist Andrew Milner, lead author of the report published Tuesday in the online journal PLoS One. But one set of tracks shows the trail of a carnivore called a theropod leaving the water and climbing up a low hill on the shore. The tracks clearly show the hind feet and, occasionally, the dragging tail. But at one point, Milner said, the theropod apparently stopped and crouched to rest. At that point, between the footprints, is the clear circular impression of the ischium or pelvis, "basically a butt print," Milner said. And to each side of the tracks are the handprints, which are mirror images of each other. They clearly show the third digit pressed into the ground and traces of the second digit, with the claw curling inward. The hands were positioned as they would be for "holding on to a basketball rather than dribbling it," Holtz said.
"Because of that, the hands could specialize as weapons, to grab on to a struggling animal or to fight with other dinosaurs," he said.
The handprints are among more than 1,200 dinosaur tracks deposited in mud along the shores of an ancient lake, then buried and fossilized. Most of the tracks are similar to ones found at other sites, said paleontologist Andrew Milner, lead author of the report published Tuesday in the online journal PLoS One.
But one set of tracks shows the trail of a carnivore called a theropod leaving the water and climbing up a low hill on the shore.
The tracks clearly show the hind feet and, occasionally, the dragging tail. But at one point, Milner said, the theropod apparently stopped and crouched to rest.
At that point, between the footprints, is the clear circular impression of the ischium or pelvis, "basically a butt print," Milner said.
And to each side of the tracks are the handprints, which are mirror images of each other. They clearly show the third digit pressed into the ground and traces of the second digit, with the claw curling inward.
The hands were positioned as they would be for "holding on to a basketball rather than dribbling it," Holtz said.
(my emphasis)
Not all dinosaurs, surely? Maybe a better statement would be "there were entirely bipedal dinosaurs from fairly early in their history". Most economists teach a theoretical framework that has been shown to be fundamentally useless. -- James K. Galbraith
