New research study addresses longstanding secret on the anatomy of the Tyrannosaurus rex jaw.
Tyrannosaurus rex dinosaurs chewed through bone by keeping a joint in their lower jaw stable like an alligator, instead of versatile like a snake, according to a research study existing at the American Association for Anatomy yearly conference throughout the Experimental Biology (EB) 2021 conference, held practically April 27-30.
The research study sheds brand-new light on a dilemma that has actually astonished paleontologists. Dinosaurs had a joint in the middle of their lower jaws, called the intramandibular joint, which is likewise present in modern-day reptiles. Previous research study has actually recommended this joint was versatile, like it remains in snakes and keep an eye on lizards, assisting meat-eating dinosaurs to keep having a hard time victim in their jaws. However, it has actually been uncertain whether the jaws were versatile at all, or how they might be strong enough to bite through and consume bone, which Tyrannosaurus did routinely, according to fossil proof.
“We discovered that these joints likely were not flexible at all, as dinosaurs like T. rex possess specialized bones that cross the joint to stiffen the lower jaw,” stated John Fortner, a doctoral trainee in anatomy at the University of Missouri, very first author of the research study.
The scientists utilized CT scans of dinosaur fossils and modern-day specimens to produce a 3D computer system design of a dinosaur jaw and recognize where muscles connect to bone. They then utilized the design to imitate muscle forces under various biting situations. Stars suggest locations where pressure was evaluated. Credit: Image thanks to John Fortner, University of Missouri
Fortner and coworkers utilized CT scans of dinosaur fossils and modern-day reptiles to construct an in-depth 3D design of the T. rex jaw. Unlike previous designs, their simulations consist of bone, tendons and specialized muscles that twist around the back of the jaw, or mandible.
“We are modeling dinosaur jaws in a way that simply has not been done before,” stated Fortner. “We are the first to generate a 3D model of a dinosaur mandible which incorporates not only an intramandibular joint, but also simulates the soft tissues within and around the jaw.”
To identify whether the intramandibular joint might preserve versatility under the forces needed to crunch through bone, the group ran a series of simulations to compute the stress that would happen at numerous points depending upon where the jaw hinged. The results recommend bone running along the within the jaw, called the prearticular, served as a pressure sink to combat flexing at the intramandibular joint, keeping the lower jaw stiff.
The group prepares to use their modeling method to other dinosaur types in order to even more clarify biting mechanics amongst dinosaurs — and possibly, assistance scientists much better comprehend today’s animals, too.
“Because dinosaur mandibles are actually built so much like living reptiles, we can use the anatomy of living reptiles to inform how we construct our mandible models,” stated Fortner. “In turn, the discoveries we make about T. rex’s mandible can provide more clarity on the diversity of feeding function in today’s reptiles like crocodilians and birds.”
Reference: “(R3068) The Role of the Intramandibular Joint, Symphyseal Tissues, and Wrapping Muscles on Theropod Dinosaur Mandibular Function” by John Fortner, 26 April 2021, Experimental Biology 2021.
