Missing 3rd finger of T.Rex’s undersized hands discovered

November 14th, 2007 - 2:26 am ICT by admin  
Researchers say the find suggests that the T. Rex had a powerful wrist and its hands were probably able to hold onto chunks of flesh while the beast’s gnarly jaws did the killing.

According to T. Rex investigator Elizabeth Quinlan of Fort Peck Paleontology, Inc, in Fort Peck, Montana, US, the newfound bone is a right metacarpal, equivalent to one of the long bones in the palm of a human hand.

“It’s unquestionably the metacarpal. There is a notch in the side of the second metacarpal that was just begging to have something fit into it,” said Quinlan.

According to a Discovery News report, no previous T. Rex remains have ever been found with a third metacarpal, despite the fact that the other bones suggested its presence.

Quinlan said the revised anatomy of the hand suggested that there was a very strong tendon that attached to the second metacarpal, giving the hand a pretty decent grip.

Still, the puny limbs were almost certainly not used by T. Rex to grapple with prey or kill, she said.

“We were thinking that T. rex did use its upper appendages not so much in hunting but in feeding. That means ripping off pieces of flesh from corpses and clutching the stuff to keep it from other hungry predators. We don’t think their table manners were very good,” said Quinlan.

“I would strongly support (the hand) being used for carrying a piece of meat away. There is a reason that carrying meat away would be useful,” said palaeontologist Scott Hartman, science director of the Wyoming Dinosaur Center in Thermopolis.

Hartman said one reason for this was that the T. Rex head was already so large and heavy that adding the weight of a large slab of meat between its teeth would make it unable to tip back and stand up.

Holding the meat with the arms, which are lower, would avoid that overloaded teeter-totter effect, he said.

He said another possibility could be that the hands served as parenting tools.

They would have made it possible for a T. Rex to carry yummy slabs of the kill to its carnivorous babies, Hartman said.

Hartman, however, said the new finger bone would not in any case cause much change to reconstructions of T. Rex.

“Throughout the evolution of meat-eating dinosaurs there was a trend towards fewer fingers, with the earliest having five fingers and the T. Rex having two. This newfound nubbin of a third finger was already on its way out, and did not stick out much,” he said.

“In another 10 million years they would have lost (the third finger) completely. Unfortunately for them, however, the age of dinosaurs ended before that could happen,” he added.

Quinlan will present her research on Oct. 28 at the annual meeting of the Geological Society of America in Denver. (ANI)

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