The Thescelosaurus neglectus, affectionately known as Willo, is an often-misunderstood dinosaur whose physical attributes have led to an underestimation of its unique sensory capabilities.
Housed at the North Carolina Museum of Natural Sciences, Willo’s recent CT scan analysis has shed light on a combination of traits that hint at a partially subterranean lifestyle.
David Button, a former Brimley Postdoctoral Scholar, utilized advanced CT scanning to digitally reconstruct soft tissues within Willo’s skull. This allowed for a detailed comparison of its sensory organs with those of other dinosaurs and their modern-day descendants.
Despite the general consensus of paleontologists regarding the Thescelosaurus as unremarkable, the latest research by Button and co-author Lindsay Zanno reveals a different story. The dinosaur’s sensory profile, characterized by a poor hearing range but an exceptional sense of smell and balance, suggests a unique adaptive strategy.
“The irony is that paleontologists generally think of these animals as pretty boring,” says Zanno, also an associate research professor at NC State. “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.”
Thescelosaurus’ hearing capabilities were limited, especially in the range of high-pitched sounds. However, its ability to detect low-frequency sounds was similar to that of the T. rex, which could have been advantageous for survival.
“We found that Thescelosaurus heard low frequency sounds best, and that the range of frequencies it could hear overlaps with T. rex,” Zanno says.
“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 olfactory bulbs of Thescelosaurus were highly developed, surpassing those of other known dinosaurs and akin to modern alligators. This heightened sense of smell might have been crucial for locating food sources such as roots and tubers.
“We found that the olfactory bulbs – the regions of the brain that process smell – were very well developed in Thescelosaurus,” Button says.
“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.”
Alongside its impressive olfactory sense, Thescelosaurus exhibited an advanced sense of balance. Such a trait is commonly associated with animals that engage in burrowing behavior, supporting the hypothesis of a semi-fossorial lifestyle.
“While we can’t say definitively that these animals lived part of their lives underground, we know that their ancestors did,” Button says. “This fact, together with their unique combination of sensory abilities, strongly suggests T. neglectus engaged in similar behaviors.”
“We still don’t know the sensory abilities of most dinosaurs,” Zanno says. “That makes it difficult to link these traits to specific lifestyles with confidence, but it also means there are plenty of cool discoveries to come.
“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.”
While it is not definitively proven that Thescelosaurus lived underground, the evidence points towards behaviors similar to its burrowing ancestors. This discovery opens up new avenues for understanding the daily lives of dinosaurs.
The North Carolina Museum of Natural Sciences is set to feature Willo in an interactive exhibit, part of the upcoming Dueling Dinosaurs experience. Visitors will have the opportunity to explore Thescelosaurus‘ world through this immersive display, slated for a 2024 launch.
In summary, the perception of Thescelosaurus neglectus as a plain and uninteresting dinosaur is now challenged. Current research has unveiled a creature with a sensory toolkit adapted for a potentially underground existence, adding a fascinating layer to our understanding of dinosaur ecology.
This study not only redefines Willo’s legacy but also paves the way for further explorations into the sensory capabilities of prehistoric life.
The full study was published in Scientific Reports.
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