大型掠食性恐龙，如霸王龙，进化出不同的眼窝形状，以允许更强的咬合力。

根据新的研究，大型掠食性恐龙，如 霸王龙 已经开发了各种形式的眼腔以更好地处理更高的咬合力。

而在包括大多数恐龙在内的许多动物中，眼窝只是头骨上包含眼球的一个圆形孔，而在较大的食肉动物中则完全不同。

一项新的研究揭示了在这些捕食者的头骨中发现的不寻常的椭圆形或椭圆形眼窝是如何进化的，以帮助头骨在猛扑猎物时吸收震动。 这项研究由科学家在 伯明翰大学，今天（2022 年 8 月 11 日）在 传播生物学。

使用原始眼窝和眼睛（左）和使用圆形眼窝和扩大的眼睛（右）进行虚拟重建的霸王龙头骨和生命重建。 图片来源：伯明翰大学 Stefan Lautschlager 博士

Stefan Luttenschlager 博士，古生物学高级讲师[{” attribute=””>University of Birmingham and author of the new study, analyzed the shape of the eye sockets of ca. 500 different dinosaurs and related species.

“The results show that only some dinosaurs had eye sockets that were elliptical or keyhole-shaped,” said Dr. Stephan Lautenschlager. “However, all of those were large, carnivorous dinosaurs with skull lengths of 1 m or more.”

Computer simulations of hypothetical dinosaur skulls. Colors indicate skull stress. High stresses occur in the skull with a round eye socket (top), lower stresses in a skull with a keyhole-shaped eye socket (bottom). Credit: Dr. Stephan Lautenschlager, University of Birmingham

Dr. Lautenschlager tested what purpose these unusual eye socket shapes could have by using computer simulations and stress analysis.

The results demonstrated that a skull with a circular eye socket was more prone to high stresses during biting. However, if these were replaced with other eye socket shapes stresses were significantly reduced. This allowed top predators, including Tyrannosaurus rex, to evolve high bite forces without compromising skull stability.

The study also showed that most plant-eating species and juvenile individuals retained a circular eye socket. Only large carnivores adopted other morphologies, such as elliptical, keyhole-shaped, or figure-of-eight-shaped eye sockets.

Skulls of different dinosaurs showing variation in eye socket shape (stippled outline). Credit: Dr. Stephan Lautenschlager, University of Birmingham

Dr. Lautenschlager added: “In these species, just the upper part of the eye socket was actually occupied by the eyeball. This also led to a relative reduction of eye size compared with skull size.”

The researchers also investigated what would have happened if eye size had increased at the same rate as skull length. In such a case, the eyes of Tyrannosaurus rex would have been up to 30 cm (12 inches) in diameter and weighed nearly 20 kg (44 pounds). This is instead of an estimated 13 cm (5 inches) and 2 kg (4.4 pounds).

Reference: “Functional and ecomorphological evolution of orbit shape in mesozoic archosaurs is driven by body size and diet” by Stephan Lautenschlager, 11 August 2022, Communications Biology.
DOI: 10.1038/s42003-022-03706-0