China News Service, Beijing, August 13th (Reporter Sun Zifa) The old Chinese saying goes, "If you gain something, you will lose something." Tyrannosaurus rex) is also evolutionarily suitable.
A new international study found that Tyrannosaurus rex and its close relatives exchanged big eyes for big bite force in the evolutionary process according to the needs of survival and reproduction.
A new paleontology paper published in Springer Nature's professional academic journal "Communications-Biology" says that Tyrannosaurus rex evolved narrower eye sockets than their ancestors, which may have helped them and similar large carnivorous dinosaurs (also known as beasts). foot dinosaurs) can bite harder.
Computer-modeled virtual dinosaur skull, with more pressure on the skull with round eye sockets (top) and less pressure on the skull with keyhole-shaped sockets (bottom) (picture from the author of the paper).
Photo courtesy of Springer Nature
The paper's author, Stephan Lautenschlager of the University of Birmingham, UK, compared the eye sockets of 410 Mesozoic (252 million to 66 million years ago) fossil samples of reptiles, including dinosaurs and their close relatives, crocodiles.
He found that most of the samples had round eye sockets, especially those of herbivores.
However, large carnivores with skull lengths greater than 1 m generally have oval or keyhole-shaped eye sockets in adulthood, although their eye sockets are more rounded in juveniles.
In addition, the eye sockets of older specimens appear to be more rounded than those of more recent specimens, and the eye sockets of large theropods are closer to the keyhole shape than their ancestors.
These observations suggest that keyhole-shaped eye sockets evolved over time in large carnivorous species, but only in adulthood, not before.
To further investigate the impact of eye socket shape on the structure and function of the skull, Stefan Lautenschlager also compared the forces during occlusion in theoretical models of reptile skulls with five different eye socket shapes, and those with circular eye sockets or keyholes. The largest eyeball size a tyrannosaurus skull model with shaped eye sockets can hold.
The comparison showed that the keyhole-shaped sockets spread the force during occlusion to the harder part of the skull behind the sockets, resulting in less deformation of the sockets and helping to reduce the pressure on the skull.
However, the tyrannosaur model with round eye sockets can hold seven times the eyeball volume than the keyhole-shaped model.
Skull and artistic reconstruction of the original eye socket eye and virtual round socket eye of Tyrannosaurus rex (image by the author of the paper).
Photo courtesy of Springer Nature
Stefan Lautenschlager believes that theropods evolved narrower eye sockets, which may have reduced the eye space in their skulls, while reserving this space for the jaw muscles and increasing the rigidity of the skull.
This may allow them to trade larger eyes for greater bite force, which had previously been suggested to enhance visual perception, and the latest findings highlight this functional trade-off that shaped dinosaur evolution.
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