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🇮🇩 Indonesia /Health & Science

T. rex's tiny arms evolved as heads grew larger, study suggests

From Tempo · () Indonesian

Translated from Indonesian and summarized by DistantNews. Read the original for the full story.

At a glance

News Named sources Context piece
  • Researchers suggest that the small arms of Tyrannosaurus rex and other theropod dinosaurs were a result of evolutionary adaptation, not a lack of function.
  • A study of 82 theropod species found a strong correlation between short arms and large, powerful heads, indicating the head took over the role of attack.
  • The research proposes that as prey became larger, theropods increasingly relied on their skulls and jaws for hunting, leading to the reduction of their forelimbs.

The famously small arms of the Tyrannosaurus rex and other theropod dinosaurs may have been a deliberate evolutionary trade-off, according to new research.

Paleontologists examined data from 82 theropod species, finding a significant link between shortened forelimbs and the development of large, robust skulls. This suggests that as these predators evolved, their heads and jaws became the primary tools for hunting, diminishing the need for their arms.

This is a case of ‘use it or lose it.’

· Charlie SchererExplaining the evolutionary reason behind the reduction of theropod forelimbs.

"This is a case of 'use it or lose it,'" stated Charlie Scherer, a paleontologist at University College London, in a statement. The study, published in Proceedings of the Royal Society B Biological Sciences, posits that the combination of massive skulls, powerful jaws, and increasingly large prey led many theropods to rely less on their arms.

We tried to understand what drives this change and found a strong relationship between short arms and a big, powerful head. The head took over the role of the arm as the method of attack.

· Charlie SchererDescribing the findings of the study correlating head size and arm length in theropods.

"We tried to understand what drives this change and found a strong relationship between short arms and a big, powerful head," Scherer explained. "The head took over the role of the arm as the method of attack."

The research team developed a new system to assess skull strength based on factors like bone connection and bite force. T. rex ranked highest for bite force, followed by Tyrannotitan. The study suggests that in species like Carnotaurus, which has even smaller arms than T. rex, this evolutionary path was driven by the need to subdue larger prey.

Carnotaurus has very small arms, smaller than T. rex.

· Charlie SchererIdentifying the dinosaur with the smallest forelimbs based on the research.
About this summary

Originally published by Tempo in Indonesian. Translated, summarized, and contextualized automatically by DistantNews, with a note on how the source frames the story. Not individually reviewed before publishing. How this works.

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