“Living Fortress”, Austrian Dinosaur Was Lonely, Slow and Had Bad Hearing

The Austrian ankylosaurs, dinosaurs belonging to a group known as “living fortresses” were solitary lives. With long spines on their necks and shoulders, these animals in the nodosaurid family were likely solitary, slow-moving and couldn’t hear very well, according to a study published in the journal Scientific Reports.

Researchers examined the braincase of this 80-million-year-old herbivore, belonging to the genus of ankylosaurids, known for their spiked club tails with a thicker tip.

The fossil of the Austrian ankylosaurus (Struthiosaurus austriacus) was, as the name implies, discovered in Austria and has been in the collection of the Swan Institute of Paleontology since the 1800s.

While some of the ankylosaurids could reach up to 8 meters in length, the Austrian is relatively smaller, at 2.7 meters in length.

To better understand the hearing and balance of these animals, the researchers studied the braincase, using a microtomography scanner, to create a 3D digital mold. Even though the brain tissue was too fragile to preserve over time, the structure of the braincase endures and can reveal aspects of dinosaur life.

What the braincase revealed

The dinosaur had a very small cerebellar flocculus. This is an important region for eye fixation when the head, neck, or body is in motion. The finding, coupled with the semicircular shape of the inner ear canals, suggests that the dinosaur moved slowly. Rounded channels allow for greater sensitivity than semicircular ones, which can interrupt the flow of vibrations and nerve impulses, according to the scientists.

In life, this animal would have been very passive and slow. Instead of acting like an aggressor, he would have “taken care of himself to survive”, says one of the study’s authors, Marco Schade, a paleontologist at the University of Greifswald in Germany. The dinosaur was not early and was able to see predators approaching.

“While some of its ‘kin’ probably defended themselves with their tails, Struthiosaurus likely relied more on its characteristic armor,” employing a passive style of self-defense, according to Schade.

The braincase also revealed the smallest cochlea ever found in a dinosaur. The cochlea is the part of the inner ear responsible for hearing — and its size can determine an animal’s hearing level.

“These observations indicate an animal that has adapted to a relatively inactive lifestyle with limited social interactions,” the researchers wrote.

not sociable

Scientists believe that many dinosaurs lived and traveled in groups, but this species of ankylosaurus possibly lived in solitude, due to its poor hearing. Struthiosaurus could be found munching on low plants in coastal regions. They had a strong bite to chew through tougher vegetation.

“The animal’s hearing was obviously not well developed and so, if necessary, Struthiosaurus communicated with each other. [com outros] in ways other than vocalization,” study co-author Cathrin Pfaff, research associate and head of the microtomography unit at the Institute of Paleontology at the University of Vienna, said in a statement.

However, Austrian ankylosaurs “were not completely incapable of hearing others,” Schade said. Like today’s tortoises, they probably made sounds to communicate only when absolutely necessary.

Now, the researchers want to examine the braincases of other European ankylosaurs, to see if these findings are specific to the Austrian species or if they represent commonalities among other dinosaurs of the same genus.