Illustration depicts family of Thescelosaurus emerging from safety to forage in the forests of the Hell Creek Formation, 66 million years ago. Some dinosaurs could once have lived underground, according to a study of the brain of a 12-foot-long herbivore. PHOTO BY ANTHONY HUTCHINGS/SWNS
Some dinosaurs could once have lived underground, according to a study of the brain of a 12-foot-long herbivore.
Thescelosaurus neglectus was a small but heavy dinosaur that lived in what is now North America over 66 million years ago.
But a CT scan of its skull allowed scientists to recreate its brain which contained a few surprises.
T. Neglectus had an amazing sense of smell and outstanding balance but appalling hearing.
Experts say that these traits are associated with living animals that spend at least part of their time underground and believe this dinosaur’s ancestors may have also done so.
The dinosaur in question, called Willo, is a specimen housed at the North Carolina Museum of Natural Sciences.
This scientific name roughly translates to “wonderful, overlooked lizard.”
Study co-author Dr. Lindsay Zanno of North Carolina University said: “The irony is that paleontologists generally think of these animals as pretty boring.
“When we first looked at our results we thought, yeah, this animal is plain as toast.
“But then we took a big step back and realized there was something unique about the combination of Willo’s sensory strengths and weaknesses.
“We have strong evidence that Thescelosaurus’ ancestors were semi-fossorial, that is to say they spent part of their time underground.
“We can’t be sure that Thescelosaurus itself spent time underground as it may have just inherited this particular set of sensory strengths and weaknesses from its ancestors, but we can say for sure it still has adaptations that make it suited for spending time underground.”
Their research also revealed that T. neglectus’ hearing range was limited, and they were only able to hear about 15 percent of the frequencies humans can detect and between four and seven percent of what dogs and cats can hear.
In particular, the dinosaur was bad at hearing high-pitched sounds but they compensated for this lack of hearing with an exceptional sense of smell.
Dr. Zanno said: “We found that Thescelosaurus heard low frequency sounds best and that the range of frequencies it could hear overlaps with T. rex.
“This doesn’t tell us they were adapted to hearing T. rex vocalize, but it certainly didn’t hurt them to know when a major predator was tooling about in the area.
“More interesting to us was the fact that these particular deficiencies are often associated with animals that spend time underground.”
The dinosaur measured around 12 feet (3.66 m) long and weighed around 750 pounds.
To find their results they used a CT scanner to reconstruct soft tissues in Willo’s skull such as the brain and inner ear.
They then compared these sensory structures to other dinosaurs and their living relatives, allowing the researchers to determine the relative size of Willo’s brain, as well as what her senses of smell, hearing, and balance were like.
Dr. David Button from Bristol University who helped with the study published in the journal Scientific Reports, said: “We found that the olfactory bulbs – the regions of the brain that process smell – were very well developed in Thescelosaurus.
“They were relatively larger than those of any other dinosaur we know of so far, and similar to those of living alligators, which can smell a drop of blood from miles away.
“Thescelosaurus may have used its similarly powerful sense of smell to instead find buried plant foods like roots and tubers.
“It also had an unusually well-developed sense of balance, helping it to pinpoint its body position in 3D space, another trait often found in burrowing animals.”
All of this evidence suggests strongly that T. Neglectus itself may have lived in burrows and confirms that their ancestors definitely lived underground.
This work is the first to link a specific sensory fingerprint with this behavior in extinct dinosaurs.
Dr. Button said: “The idea that there might have been dinosaurs living under the feet of T. rex and Triceratops is fascinating. No matter what, we now know for certain that T. neglectus isn’t boring.”
Produced in association with SWNS Talker
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