CT scans of the skull of a little-known plant-eating dinosaur reveal that while it may not have been particularly "intelligent," it had a unique set of characteristics similar to those of today's animals that live partially underground, including a superb sense of smell and excellent balance. This study is the first to link specific sensory fingerprints to this behavior in extinct dinosaurs.
This dinosaur is named Willow and is a specimen collected by the North Carolina Museum of Natural Sciences. Willow was a Thescelosaurus neglectus - a small (12 feet or 3.6 meters long) but heavy (750 pounds or 340 kilograms) herbivorous dinosaur that lived in what is now North America before the end-Cretaceous mass extinction event 66 million years ago.
Willow's scientific name roughly translates to "wonderful, neglected lizard." But David Button, a former postdoctoral scholar at the North Carolina Museum of Natural Sciences and North Carolina State University, decided to take a closer look at the "neglected" dinosaur skull. Barton is currently a research associate at the University of Bristol, UK.
Patton used a CT scanner to reconstruct soft tissues in Willow's skull that had been lost to the fossilization process, such as the brain and inner ear. The researchers compared these sensory structures to those of other dinosaurs and their living relatives, allowing them to determine the relative size of Willow's brain, as well as her senses of smell, hearing and balance.
"The irony is that paleontologists often think of these animals as being very boring," said Lindsay Zanno, an associate researcher at North Carolina State University, chief of paleontology at the North Carolina Museum of Natural Sciences and co-author of the work. "When we first saw our results, we thought, yes, this animal is as bland as toast. But then we took a big step back and realized there was something unique about Willow's combination of sensory strengths and weaknesses."
Patton and Zano determined that Chilosaurus had a limited hearing range. This dinosaur could only hear 15% of the frequencies that humans can hear, and 4% to 7% of the frequencies that dogs and cats can hear. Especially high-pitched sounds cannot be heard.
"We found that Diosaurus was best at hearing low-frequency sounds, and it could hear in a frequency range that overlapped with T. rex," Zano said. "That doesn't tell us that they had adapted to hear T. rex vocalizations, but it certainly didn't hurt to know when a major predator was in the area. What's even more interesting to us is that these particular deficiencies tend to be associated with animals that live underground."
Archaeologists have found that Diminisaurus balanced its poor hearing with an excellent sense of smell: "We found that Diminisaurus's olfactory bulbs - the area of the brain that processes smell - were so well developed that they were larger than those of any other dinosaur we currently know of, and were similar to those of living crocodiles, which could count numbers. Smell a drop of blood from miles away. "Anthropus may have used its equally powerful sense of smell to find buried plant foods such as roots and tubers. It also had an unusually developed sense of balance, which helped it accurately orient itself in three-dimensional space, a trait often shared by burrowing animals."
The poor cognitive and auditory abilities of O. mirabilis , coupled with strong limbs, an overdeveloped sense of smell and balance, are characteristics of today's animals that live underground and/or engage in burrowing behavior.
"While we can't say with certainty that these animals lived part of their lives underground, we do know that their ancestors did. This fact, coupled with their unique combination of sensory abilities, strongly suggests that Mysterosaurus behaved similarly," Barton said.
"We still don't know the sensory capabilities of most dinosaurs," Zano said. "This makes it difficult to confidently link these traits to a specific lifestyle, but it also means there are a lot of cool discoveries to be made in the future. The idea that T. rex and Triceratops could have dinosaurs living under their feet is very appealing. Regardless, we now know for sure that Mysterosaurus itself was not boring."
Compiled source: ScitechDaily