Grote roofzuchtige dinosaurussen, zoals de T. rex, ontwikkelden verschillende oogkasvormen om sterkere beten mogelijk te maken.

Volgens nieuw onderzoek, grote roofzuchtige dinosaurussen zoals: Tyrannosaurus Rex Er zijn verschillende vormen van oogholtes ontwikkeld om hogere bijtkrachten beter aan te kunnen.

Terwijl bij veel dieren, waaronder de meeste dinosauriërs, de oogkas slechts een cirkelvormig gat in de schedel is dat de oogbol bevat, is dit heel anders bij grotere carnivoren.

Een nieuwe studie heeft onthuld hoe de ongebruikelijke ovale of ovale oogkassen die in de schedels van deze roofdieren worden gevonden, zijn geëvolueerd om de schedel te helpen schokken op te vangen wanneer deze op een prooi bespringt. Dit onderzoek door wetenschappers in Universiteit van Birminghamvandaag (11 augustus 2022) gepubliceerd in Communicatie Biologie.

Schedel- en levensreconstructies in Tyrannosaurus Rex met de originele oogkas en oog (links) en virtuele reconstructie met behulp van een cirkelvormige oogkas en vergroot oog (rechts). Krediet: Dr. Stefan Lautschlager, Universiteit van Birmingham

Dr. Stefan Luttenschlager, hoofddocent paleobiologie bij[{” 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