Great-bellied fused lizard
Cretaceous Period, 68-66 MYA
Countries in North America
20 feet long, 5.5 feet tall at the hips, 6 tons
- Ankylosaurus had unusually complex sinuses within its nasal passage. While the exact function of these cavities is unknown, several theories have been proposed. One is that the passages served to lighten the skull and enhance the animal’s sense of smell. Another is that they acted to help cool the brain, as the lengthened passages would have been covered in a high volume of mucosa membrane that could facilitate the exchange of heat and water. Other paleontologists believe the hollow space functioned as a resonating chamber to amplify vocalizations and indeed, the inner ear of Ankylosaurus is adapted to pick up low frequency sounds.
- Exactly how Ankylosaurus processed its food is a matter of debate. With its broad, beaked snout, it would appear that the animal is adapted for browsing vegetation fairly close to the ground. Wear patterns on the teeth and the presence of a secondary palate suggest they could chew, but the greatly expanded hips seem to support the idea that this animal relied on hindgut fermentation to digest softer, less abrasive plants. Ankylosaurs also had well developed hyoid bones, which has lead some scientists to speculate that these animals may have had long, muscular, protrusible tongues to help them bring food into their mouths and that some may have even been partially insectivorous.
Ankylosaurus was literally like a living tank. Its body was covered with osteoderms ranging from half an inch to over a foot in diameter that acted as nigh-impenetrable armor. Even the eyelids were armored. The only part of the body without protection was the underbelly, but due to the animal’s short stature this was not a readily available target for predators. Due to their short legs and heavy build, Ankylosaurus were not able to flee from predators. Instead, they stood their ground and relied on their armor. When that failed, they had one more defensive weapon they could bring out for protection. An Ankylosaur tail is heavily muscled and flexible at the base, but the more distal half consists of interlocked and fused vertebrae ending in bony club. These clubs could weigh over 100 pounds and were held off the ground at a similar height to the ankle joints of large theropods. Biomechanics tests indicate the club could withstand several tons of impact force and was believed to have been used like a medieval mace.
Kingdom - Animalia Phylum - Chordata Class - Reptilia Order - Ornithischia Family - Ankylosauridae Genus - Ankylosaurus Species - A. magniventris