Scientists say T-rex had complex sensing nerves in its jaw

Using CT scans, researchers inferred that the T-rex’s fearsome jaw may have also had a sophisticated system of sensing nerves.

Of all dinosaurs, the Tyrannosaurus rex stands as one of the most iconic and recognisable prehistoric creatures. Central to this is its ferocious-looking jaw.

Now, a new study has rendered this particular feature in heightened detail as researchers used computed tomography (CT) to reconstruct the neurovascular canal of a fossilised T-rex mandible.

“T-rex was an even more fearsome predator than previously believed,” explained lead author Soichiro Kawabe from the Institute of Dinosaur Research at Fukui Prefectural University in Japan.

“Our findings show the nerves in the mandible (an area of the jaw) of Tyrannosaurus rex is more complexly distributed than those of any other dinosaurs studied to date, and comparable to those of modern-day crocodiles and tactile-foraging birds, which have extremely keen senses.”

The subject of the researchers’ analysis was a fossil mandible found in Hell Creek Formation, Montana. The CT analysis was complemented by reconstructions of other dinosaurs, such as the Triceratops, along with comparisons with modern crocodiles and birds.

Hypothesised distribution of nerves in the mandible of Tyrannosaurus (orange). Image: Historical Biology

From this, researchers could tell that the T-rex was able to differentiate variations in materials and movement. The research also suggests, when taken with analyses of another tyrannosaurid and the neurovascular canal morphology of an allosaurid, that therapods (a group of biped dinosaurs including the T-rex) had highly sensitive facial regions.

“The neurovascular canal with branching pattern as complex as that of the extant crocodilians and ducks, suggests that the trigeminal nervous system in Tyrannosaurus probably functioned as a sensitive sensor in the snout,” said Kawabe.

“It must be noted that the sensitivity of the snout in Tyrannosaurus may not have been as enhanced as that of the crocodilians because Tyrannosaurus lacks the thick neural tissue occupying the neurovascular canal unlike extant crocodiles.”

Soki Hattori, an assistant professor and co-author on the study, added that the jaw was also perhaps used for more than crunching prey.

“These inferences also suggest that, in addition to predation, tyrannosaurids’ jaw tips were adapted to perform a series of behaviours with fine movements including nest construction, parental care and intraspecific communication.”