Tyrannosaurus rex's jaw had sensors to make it an even more fearsome
predator

Date:
August 24, 2021
Source:
Taylor & Francis Group
Summary:
Tyrannosaurus rex was not just a huge beast with a big bite,
it had nerve sensors in the very tips of its jaw enabling it to
better detect -- and eat -- its prey, a new study finds.



FULL STORY ========================================================================== Tyrannosaurus rex was not just a huge beast with a big bite, it had
nerve sensors in the very tips of its jaw enabling it to better detect --
and eat - - its prey, a new study published in the peer-reviewed journal Historical Biology today finds.


==========================================================================
"T. rex was an even more fearsome predator than previously believed,"
explains lead author Dr 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.

"What this means is that T. rex was sensitive to slight differences in
material and movement; it indicates the possibility that it was able
to recognize the different parts of their prey and eat them differently depending on the situation.

"This completely changes our perception of T. rex as a dinosaur that was insensitive around its mouth, putting everything and anything in biting
at anything and everything including bones." Whilst the morphology
of vessels and nerves in the jaw have been analysed in several fossil
reptiles, this study is the very first investigation of the internal
structure of the mandible of T. rex.



==========================================================================
Dr Kawabe, who was joined by Dr Soki Hattori Assistant Professor at the Institute of Dinosaur Research, used computed tomography (CT) to analyse
and reconstruct the distribution neurovascular canal of a fossil mandible
of T.

rex, which was originally found in Hell Creek Formation, Montana.

They then compared their reconstruction to other dinosaurs such as
Triceratops, as well as living crocodiles and birds.

This enabled the researchers to describe the well-preserved canals that
houses the vessels and nerves in dentary of Tyrannosaurus rex.

"The present study reveals the presence of neurovascular canals with
complex branching in the lower jaw of Tyrannosaurus, especially in the
anterior region of the dentary, and it is assumed that a similarly complex branching neurovascular canal would also be present in its upper jaw,"
says Dr Kawabe.

He added: "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.



==========================================================================
"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.

"Nevertheless, the sensitivity of the snout of Tyrannosaurus was
considerably greater than that of the ornithischian dinosaurs compared
in this study." The results of the paper are consistent with analyses
of the skull surface of another tyrannosaurid, Daspletosaurus, and
the neurovascular canal morphology within the maxilla of allosaurid
Neovenator, which indicate that the facial area of theropods may have
been highly sensitive.

"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," Dr Hattori adds.

Limitations of the study include the team not analysing
the full mandible area of T. rex and other dinosaurs used
for comparison, however as the proportion not researched is
insignificant, the trend shown "should be a reasonable estimate." ========================================================================== Story Source: Materials provided by Taylor_&_Francis_Group. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Soichiro Kawabe, Soki Hattori. Complex neurovascular system in the
dentary of Tyrannosaurus. Historical Biology, 2021; 1 DOI: 10.1080/
08912963.2021.1965137 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210824083443.htm

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