Scientists Finally Figured Out How The T. Rex Used Its Hilariously Tiny Arms

Friday, 19 October 2018 - 11:12AM
Friday, 19 October 2018 - 11:12AM
Scientists Finally Figured Out How The T. Rex Used Its Hilariously Tiny Arms
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The Tyrannosaurus rex is generally respected as an apex predator and king of the dinosaurs – but it's those tiny arms that most people just can't take seriously. According to a recent study, those stubby arms may have actually been useful due to their unique range of motion.

Because they didn't have a T. rex handy (and because Barney isn't built to scale), researchers at Stockton University in New Jersey studied the soft joint tissue of distant relatives of the predatory lizard: the domestic turkey and the American alligator. Using X-ray Reconstruction of Moving Morphology (XROMM) and fishing wire to move the elbows of the dismembered limbs, the scientists were able to create virtual models to see and reconstruct how the joints moved.

What they discovered was that theropods like the T. rex probably had the ability to turn their hands so that their palms faced their chests instead of the ground. "The elbow joint is more complex," co-researchers Christopher Langel and Matthew Bonnan told LiveScience, "and both bones in the forearm not only pivot around the joint, but [also] rock sideways toward the upper arm bone as the elbow is flexed. Unlike our elbows, both forearm bones [in alligators and turkeys] cause the palm of the hand to turn inward and somewhat upward...we might speculate that such a movement (rotating the forearm and hand in toward the chest) could allow some theropods to bring prey in close for a bite."

Previous scientific discussions of T. rex anatomy have pointed out that while the dinosaur's arms were small in relation to its body and head, each limb was around three feet long with long claws designed for ripping and shredding. Compound that with the ability to turn its hands over and you have even more of a threat (not to mention the arms are located just feet away from a massive and spiky mouth). So the next time you joke about "Rexy's" disproportionate build, remember that it could still have messed you up pretty badly – turkey arms or no.

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