as more abundant foliage. Stomach contents of the closely related taxon Borealopelta were identified amongst gastroliths, showing that at least it had a diet regularly consisting of almost 85% fern material, along with 3.7% cycad matter, trace elements of conifers, and 11.4% undiagnostic plant remains. Gastroliths may have been found with Panoplosaurus as well, but their identification is uncertain as they were not originally mentioned among the material found as part of the specimen. Airways and senses While nodosaurids were traditionally thought to have had simply sinuses, lacking complicated cavities and paranasal sinuses. While this can be seen in some taxa like Edmontonia, the nasal system of Panoplosaurus is far more complex than previously thought. The complete nasal passage of Panoplosaurus undergoes two complete 360 degree loops in different planes along its length, before entering the olfactory recess for scent processing. However, while the shape of the nasal passages is more complicated, Panoplosaurus does lack the additional parallel sinus tracts that can be found in ankylosaurids like Euoplocephalus. It is possible that the function of these complicated sinuses was to warm incoming air as it passed through the skull. Inflowing air in Panoplosaurus was simulated to undergo a raise of between , primarily in the elongate nasal passage, while saturating the air with moisture. This is less heat efficient than the more complicated sinuses of Euoplocephalus, but still shows that the sinus cavities of Panoplosaurus increased the recovery of lost heat and moisture by over 60%. The brain of Panoplosaurus takes up 33% of the length of the skull, similar to the nodosaurid Pawpawsaurus where the value is 30%, a higher value than in ankylosaurids. Panoplosaurus had a similar sense of smell to both Pawpawsaurus and Euoplocephalus, with the ratio between the length of the olfactory bulb and cerebral hemisphere being 44.0, 46.2 and 54.0 respectively. However, the size of the region of the brain devoted to the sense of smell is smaller in Panoplosaurus than expected for an animal of its size. Paleoecology The Dinosaur Park Formation deposits are a layer of sediments exposed in the badlands of Alberta, lying on top of the older Oldman Formation and underneath the younger Bearpaw Formation. Panoplosaurus was found about above boundary with the Oldman Formation, which is 76.5 million years old, within the "sandy zone" of the formation deposited by alluvial paleochannels. All the deposits of the Dinosaur Park Formation were