Posted on 05/09/2021 5:49:15 AM PDT by ETL
A small bone in the mandible helped brace an otherwise flexible joint
The fearsome Tyrannosaurus rex could generate tremendous bone-crushing bite forces thanks to a stiff lower jaw. That stiffness stemmed from a boomerang-shaped bit of bone that braced what would have been an otherwise flexible jawbone, a new analysis suggests.
Unlike mammals, reptiles and their close kin have a joint dubbed the intramandibular joint within their lower jawbone, or mandible. New computer simulations show that with a bone spanning the IMJ, T. Rex could have generated bite forces of more than 6 metric tons, or about the weight of a large male African elephant, researchers reported April 27 at the virtual annual meeting of the American Association of Anatomy.
(Excerpt) Read more at sciencenews.org ...
So you are only interested in things that are “vital to the continued existence of humanity”? You must be a lot of fun to be around.
I always wondered why depictions of T-Rex have such small arms and hands.
They flop around and seem useless.
It’s not as if those arms can bring food the the animals mouth, or are even remotely useful in a fight.
It’s all guessing. Probably an added element of GIGO.
T-rex arms, although tiny, were actually packed with muscles and pretty strong. They were probably used to help hold prey and to better “hang on” during sex.
Educated, informed, guessing.
Meh, do not buy that line, given position of the arms and the size of the animals chest
John Pickrell [National Geographic]
Nov 2, 2017
The precise purpose of T. rex’s relatively tiny arms has long been mysterious. Over the years, scientists have suggested that they might have been used to grasp struggling prey, to help resting dinosaurs push themselves up from the ground, or to grip tight to mates during sex.
Whatever their limited use, the consensus in recent years seemed to be that they were vestigial, hanging around as an evolutionary remnant from T. rex’s ancestors, a little like the wings of flightless birds. Perhaps, some scientists even suggested, small arms were a necessary trade-off in order to support such huge and powerful head and neck muscles.
But now one researcher argues that we’ve got it all wrong. Steven Stanley, a paleontologist at the University of Hawaii in Manoa, believes Tyrannosaurus’ arms were well-adapted for “vicious slashing” at close quarters, making use of four-inch-long claws to inflict deep wounds on unfortunate prey.
“Its short, strong forelimbs and large claws would have permitted T. rex, whether mounted on a victim’s back or grasping it with its jaws, to inflict four gashes a meter [three feet] or more long and several centimeters [more than an inch] deep within a few seconds,” said Stanley. “And it could have repeated this multiple times in rapid succession.”
Since related dinosaurs also slashed their prey, “in light of its formidable weaponry, why should T. rex not have engaged in this activity?” asks Stanley, who presented his findings last week in Seattle at a meeting of the Geological Society of America. (Read about research suggesting that T. rex was not as fast a runner as previously thought.)
To make his case, the scientist points to T. rex’s strong arm bones, which would have made effective slashing tools, while an “unusual quasi-ball-and-socket joint” would have allowed the arms to move in several directions, ideal for slashing, he says.
What’s more, tyrannosaurs lost one of their three claws during the course of evolution, resulting in 50 percent more pressure being able to be applied by each of the two remaining claws—all the better for a powerful slash.
Slash or Sex?
Other experts are yet to be persuaded, however. “It seems illogical to me to use such small arms to slash with,” said Jakob Vinther, a paleobiologist from the University of Bristol in the U.K. who attended the presentation.
Without further evidence, he favors the idea of the arms being used for a “minor subsidiary purpose,” such as to clasp a partner during sex, despite Stanley’s claim that the claws would have been dangerous to use while mating.
The three-foot-long arms would also give a full-grown T. rex an awkwardly short reach for slashing, said Thomas Holtz, a tyrannosaur expert at the University of Maryland in College Park. (Find out what it would have felt like to pet a T. rex.)
The chest is so broad on a mature T. rex, he noted, that the “effective strike zone” of the swiping arm couldn’t be far from the animal’s torso. “I would expect it could cause some decent damage if it struck, but in order to deploy [the arm], Tyrannosaurus would basically have to push its chest up against the side of the victim,” Holtz said. “In such a position the tyrannosaur wouldn’t be able to use its far more powerful armament: its massively powerful jaws.”
During its lengthy juvenile years, though, Holtz conceded that a T. rex’s arms would have been larger relative to its body.
“It might be that the arms were actually more functional in young T. rex, and became reduced in function as it became older,” he says. “The strike zone would be proportionately larger in a young T. rex—and going after smaller prey would mean the force required to kill the victim would be less.”
Stanley agrees with critics that the arms atrophied during tyrannosaur evolution, with the giant jaws taking over their grasping function. But, he argues, the little arms stuck around as the dinosaurs opportunistically put them to use once more for slashing at close quarters.
Still, it's just a Jeepster for our love. Thanks ETL.
You can stop trying, I read all that stuff.
No sale
Stiff lower lip? Must’ve gone to Hahvahd.
Their arms were small because the cell phones at the time were small, just like today.
Not sure what that means, but I do know T-rex loved to chase Jeepsters and other similar vehicles...
:)
YEARS ago, I read that some scientists were studying why Australian Aborigines didn't sweat and thought "oversupply of grant money". Then I read that NASA was concerned about keeping the astronauts from sweating too much or nor at all.
I now read these discoveries with a little less knee-jerk reaction.
Good example!
Thanks.
Humans studied birds to help develop the earliest gliders, which led to the first airplane. The shape of whales is mimicked in the hydrodynamic designs of modern submarines. The idea for Velcro came from observing how burdock stuck to clothes and the fur of the inventor’s dog.
Today’s bullet trains have a nose section patterned after the shape of the kingfisher. The beaked front in birds help them minimise air pressure when they fly or plunge into water.
A scuba diver’s flippers are patterned after ducks’ webbed feet.
There are many other examples, and ongoing research continues. Studies of an alligator’s ability to survive in murky waters with open wounds that don’t get infected may help develop new medical technology. The strength of spider webs may inspire better bullet proof vests.
You mean like Pit Bulls?
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Excellent.
Thanks.
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