AsianScientist (Jul. 10, 2018) – A research group in China, collaborating with scientists in the US, has found that dinosaur tongues were probably rooted to the bottoms of their mouths in a manner akin to alligators. They published their findings in PLOS One.
Dinosaurs are often depicted as fierce creatures, baring their teeth, with tongues wildly flicking from their mouths like giant, deranged lizards. However, in this study, researchers from the Chinese Academy of Sciences, China, and the University of Texas at Austin, US, demonstrated that dinosaurs were unlikely to have been able to stick out their tongues.
They made the discovery by comparing the hyoid bones—the bones that support and ground the tongue—of modern birds and crocodiles with those of their extinct dinosaur relatives. The process involved taking high-resolution images of hyoid muscles and bones from 15 modern specimens, including three alligators and 13 bird species.
The fossil specimens, most of which were from northeastern China, included small bird-like dinosaurs, pterosaurs and a Tyrannosaurus rex. They were scrutinized for preservation of the delicate tongue bones. The results indicate that hyoid bones of most dinosaurs were like those of alligators and crocodiles—short, simple and connected to a tongue that was not very mobile.
In contrast to the short hyoid bones of crocodiles, the researchers found that pterosaurs, bird-like dinosaurs and living birds have a great diversity in hyoid bone shapes. They hypothesized that the range of bone shapes could be related to flight ability. Taking to the skies could have led to new ways of feeding that could be tied to tongue diversity and mobility, said the researchers.
“Tongues are often overlooked, but they offer key insights into the lifestyles of extinct animals,” said lead author Associate Professor Li Zhiheng at the Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences.
Further research on other anatomical changes that occurred with shifts in tongue function could help improve our knowledge of the evolution of birds, the authors said.
The article can be found at: Li et al. (2018) Convergent Evolution of a Mobile Bony Tongue in Flighted Dinosaurs and Pterosaurs.
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Source: Chinese Academy of Sciences; Photo: Spencer Wright.
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