Paleontologists at St. Petersburg University have created the most detailed 3D virtual model of the endocranial cast and blood vessels of the head of the ankylosaurus Bissektipelta archibaldi. About this writes the journal Biological Communications.
Bissektipelta archibaldi is a herbivorous dinosaur, somewhat similar to a modern battleship. The first three-dimensional computer reconstruction of a dinosaur made in Russia, namely a digital cast of his brain, helped scientists. This made it possible to find out that ankylosaurs were able to cool the brain, had an extremely developed sense of smell, and heard low-frequency sounds. However, their brain was one and a half times smaller than that of modern animals of the same size.
Ankylosaurs appeared on Earth in the middle of the Jurassic – about 160 million years ago and existed until the end of the dinosaur era, which ended 65 million years ago. These herbivorous animals were somewhat reminiscent of modern turtles or armadillos, were covered with thick armor, and sometimes even had a bone club on the tail. Researchers became interested in the uniquely preserved remains of ankylosaurs from Uzbekistan. Although these fossils have been known for 20 years, only now scientists have a unique opportunity to study samples from the inside, using the most modern methods.
During the study, paleontologists examined three fragments of fossil skulls of the ankylosaurus Bissektipelta archibaldi. They were discovered during a series of international expeditions URBAC in the late 1990s and early 2000s in the Dzharakuduk area in the desert of Central Kyzylkum, Uzbekistan. Scientists emphasize that the place is unique in that here you can find numerous remains of various representatives of the ancient fauna (about 90 million years ago). These include dinosaurs, pterosaurs, crocodiles, birds, mammals and other vertebrates.
The material that was collected at that time consists of dozens of fragments of skulls and skeletons and hundreds of thousands of isolated bones. Scientists still use them in their research and say that this is enough for many years.
After painstaking work, which lasted three years, scientists were able to find out that a significant part of the brain of the Bissektipelta archibaldi was occupied by the olfactory bulbs, which, incidentally, is about 60% of the size of the cerebral hemispheres. They could boast of an extremely developed sense of smell, which probably helped them to search for food, dinosaurs of the opposite sex and in time to feel the approach of predators. It was imperative to be aware of any danger in advance, because the ankylosaurs had very heavy armor and a clumsy figure. The smell of ankylosaurs can even be compared with the smell of the famous predator Tyrannosaurus rex. Its olfactory bulbs were even larger, since they occupied about 65-70% of the size of the cerebral hemispheres.
Another interesting skill of the ankylosaurus is the ability to cool its brain. The network of veins and arteries in his brain was very complex. Blood could flow in different directions and redistributed, maintaining the optimal brain temperature of the animal. For example, if the upper part of the head of the ankylosaurus warmed up, the vessels quickly diverted warm blood and created a screening effect – as if a dinosaur was putting on a hat from the sun.
Paleontologists managed to inspect the inner ear of an ancient animal. Its anatomy suggests the frequency of sounds that the ankylosaurus could hear. The range turned out to be from 300 to 3000 hertz – modern crocodiles hear in the same range. These are quite low frequencies that correspond to the relatively large sizes of ankylosaurs. The larger the modern animals, the more low-frequency sounds they make and hear. Paleontologists have suggested that during evolution, ankylosaurs increased in size, and therefore later formed sounds of even lower frequencies.
The mass of their brain turned out to be at least half that expected, based on a comparison with modern animals – about 26.5 grams for a three-meter dinosaur. Its brain size can be compared to two walnuts. However, ankylosaurs have existed on the planet for 100 million years. They were quite successful in terms of evolution. However, judging by the size of their olfactory bulbs, they sniffed a little faster than they thought.